Ejemplo n.º 1
0
    def primerange(self, a, b):
        """Generate all prime numbers in the range [a, b).

        Examples
        ========

        >>> from sympy import sieve
        >>> print([i for i in sieve.primerange(7, 18)])
        [7, 11, 13, 17]
        """
        from sympy.functions.elementary.integers import ceiling

        # wrapping ceiling in int will raise an error if there was a problem
        # determining whether the expression was exactly an integer or not
        a = max(2, int(ceiling(a)))
        b = int(ceiling(b))
        if a >= b:
            return
        self.extend(b)
        i = self.search(a)[1]
        maxi = len(self._list) + 1
        while i < maxi:
            p = self._list[i - 1]
            if p < b:
                yield p
                i += 1
            else:
                return
Ejemplo n.º 2
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def test_issue_8413():
    x = Symbol('x', real=True)
    # we can't evaluate in general because non-reals are not
    # comparable: Min(floor(3.2 + I), 3.2 + I) -> ValueError
    assert Min(floor(x), x) == floor(x)
    assert Min(ceiling(x), x) == x
    assert Max(floor(x), x) == x
    assert Max(ceiling(x), x) == ceiling(x)
Ejemplo n.º 3
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    def _intersect(self, other):
        from sympy.functions.elementary.integers import floor, ceiling
        from sympy.functions.elementary.miscellaneous import Min, Max
        if other.is_Interval:
            osup = other.sup
            oinf = other.inf
            # if other is [0, 10) we can only go up to 9
            if osup.is_integer and other.right_open:
                osup -= 1
            if oinf.is_integer and other.left_open:
                oinf += 1

            # Take the most restrictive of the bounds set by the two sets
            # round inwards
            inf = ceiling(Max(self.inf, oinf))
            sup = floor(Min(self.sup, osup))
            # if we are off the sequence, get back on
            off = (inf - self.inf) % self.step
            if off:
                inf += self.step - off

            return Range(inf, sup + 1, self.step)

        if other == S.Naturals:
            return self._intersect(Interval(1, S.Infinity))

        if other == S.Integers:
            return self

        return None
Ejemplo n.º 4
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    def __new__(cls, *args):
        from sympy.functions.elementary.integers import ceiling
        # expand range
        slc = slice(*args)
        start, stop, step = slc.start or 0, slc.stop, slc.step or 1
        try:
            start, stop, step = [w if w in [S.NegativeInfinity, S.Infinity] else S(as_int(w))
                                 for w in (start, stop, step)]
        except ValueError:
            raise ValueError("Inputs to Range must be Integer Valued\n" +
                    "Use ImageSets of Ranges for other cases")

        if not step.is_finite:
            raise ValueError("Infinite step is not allowed")
        if start == stop:
            return S.EmptySet

        n = ceiling((stop - start)/step)
        if n <= 0:
            return S.EmptySet

        # normalize args: regardless of how they are entered they will show
        # canonically as Range(inf, sup, step) with step > 0
        if n.is_finite:
            start, stop = sorted((start, start + (n - 1)*step))
        else:
            start, stop = sorted((start, stop - step))

        step = abs(step)
        if (start, stop) == (S.NegativeInfinity, S.Infinity):
            raise ValueError("Both the start and end value of "
                             "Range cannot be unbounded")
        else:
            return Basic.__new__(cls, start, stop + step, step)
Ejemplo n.º 5
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    def search(self, n):
        """Return the indices i, j of the primes that bound n.

        If n is prime then i == j.

        Although n can be an expression, if ceiling cannot convert
        it to an integer then an n error will be raised.

        Examples
        ========

        >>> from sympy import sieve
        >>> sieve.search(25)
        (9, 10)
        >>> sieve.search(23)
        (9, 9)
        """
        from sympy.functions.elementary.integers import ceiling

        # wrapping ceiling in int will raise an error if there was a problem
        # determining whether the expression was exactly an integer or not
        test = int(ceiling(n))
        n = int(n)
        if n < 2:
            raise ValueError("n should be >= 2 but got: %s" % n)
        if n > self._list[-1]:
            self.extend(n)
        b = bisect(self._list, n)
        if self._list[b - 1] == test:
            return b, b
        else:
            return b, b + 1
Ejemplo n.º 6
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 def eval(cls, ar, period):
     # Our strategy is to evaluate the argument on the Riemann surface of the
     # logarithm, and then reduce.
     # NOTE evidently this means it is a rather bad idea to use this with
     # period != 2*pi and non-polar numbers.
     if not period.is_positive:
         return None
     if period == oo and isinstance(ar, principal_branch):
         return periodic_argument(*ar.args)
     if isinstance(ar, polar_lift) and period >= 2*pi:
         return periodic_argument(ar.args[0], period)
     if ar.is_Mul:
         newargs = [x for x in ar.args if not x.is_positive]
         if len(newargs) != len(ar.args):
             return periodic_argument(Mul(*newargs), period)
     unbranched = cls._getunbranched(ar)
     if unbranched is None:
         return None
     if unbranched.has(periodic_argument, atan2, atan):
         return None
     if period == oo:
         return unbranched
     if period != oo:
         n = ceiling(unbranched/period - S(1)/2)*period
         if not n.has(ceiling):
             return unbranched - n
Ejemplo n.º 7
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    def mobiusrange(self, a, b):
        """Generate all mobius numbers for the range [a, b).

        Parameters
        ==========

        a : integer
            First number in range

        b : integer
            First number outside of range

        Examples
        ========

        >>> from sympy import sieve
        >>> print([i for i in sieve.mobiusrange(7, 18)])
        [-1, 0, 0, 1, -1, 0, -1, 1, 1, 0, -1]
        """
        from sympy.functions.elementary.integers import ceiling

        # wrapping ceiling in as_int will raise an error if there was a problem
        # determining whether the expression was exactly an integer or not
        a = max(1, as_int(ceiling(a)))
        b = as_int(ceiling(b))
        n = len(self._mlist)
        if a >= b:
            return
        elif b <= n:
            for i in range(a, b):
                yield self._mlist[i]
        else:
            self._mlist += _azeros(b - n)
            for i in range(1, n):
                mi = self._mlist[i]
                startindex = (n + i - 1) // i * i
                for j in range(startindex, b, i):
                    self._mlist[j] -= mi
                if i >= a:
                    yield mi

            for i in range(n, b):
                mi = self._mlist[i]
                for j in range(2 * i, b, i):
                    self._mlist[j] -= mi
                if i >= a:
                    yield mi
Ejemplo n.º 8
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 def _intersect(self, other):
     from sympy.functions.elementary.integers import floor, ceiling
     if other is Interval(S.NegativeInfinity, S.Infinity) or other is S.Reals:
         return self
     elif other.is_Interval:
         s = Range(ceiling(other.left), floor(other.right) + 1)
         return s.intersect(other)  # take out endpoints if open interval
     return None
Ejemplo n.º 9
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 def _eval_evalf(self, prec):
     z, period = self.args
     if period == oo:
         unbranched = periodic_argument._getunbranched(z)
         if unbranched is None:
             return self
         return unbranched._eval_evalf(prec)
     ub = periodic_argument(z, oo)._eval_evalf(prec)
     return (ub - ceiling(ub/period - S(1)/2)*period)._eval_evalf(prec)
Ejemplo n.º 10
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    def _eval_aseries(self, n, args0, x, logx):
        from sympy import Order
        if args0[1] != oo or not \
                (self.args[0].is_Integer and self.args[0].is_nonnegative):
            return super(polygamma, self)._eval_aseries(n, args0, x, logx)
        z = self.args[1]
        N = self.args[0]

        if N == 0:
            # digamma function series
            # Abramowitz & Stegun, p. 259, 6.3.18
            r = log(z) - 1/(2*z)
            o = None
            if n < 2:
                o = Order(1/z, x)
            else:
                m = ceiling((n + 1)//2)
                l = [bernoulli(2*k) / (2*k*z**(2*k)) for k in range(1, m)]
                r -= Add(*l)
                o = Order(1/z**(2*m), x)
            return r._eval_nseries(x, n, logx) + o
        else:
            # proper polygamma function
            # Abramowitz & Stegun, p. 260, 6.4.10
            # We return terms to order higher than O(x**n) on purpose
            # -- otherwise we would not be able to return any terms for
            #    quite a long time!
            fac = gamma(N)
            e0 = fac + N*fac/(2*z)
            m = ceiling((n + 1)//2)
            for k in range(1, m):
                fac = fac*(2*k + N - 1)*(2*k + N - 2) / ((2*k)*(2*k - 1))
                e0 += bernoulli(2*k)*fac/z**(2*k)
            o = Order(1/z**(2*m), x)
            if n == 0:
                o = Order(1/z, x)
            elif n == 1:
                o = Order(1/z**2, x)
            r = e0._eval_nseries(z, n, logx) + o
            return (-1 * (-1/z)**N * r)._eval_nseries(x, n, logx)
Ejemplo n.º 11
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    def totientrange(self, a, b):
        """Generate all totient numbers for the range [a, b).

        Examples
        ========

        >>> from sympy import sieve
        >>> print([i for i in sieve.totientrange(7, 18)])
        [6, 4, 6, 4, 10, 4, 12, 6, 8, 8, 16]
        """
        from sympy.functions.elementary.integers import ceiling

        # wrapping ceiling in as_int will raise an error if there was a problem
        # determining whether the expression was exactly an integer or not
        a = max(1, as_int(ceiling(a)))
        b = as_int(ceiling(b))
        n = len(self._tlist)
        if a >= b:
            return
        elif b <= n:
            for i in range(a, b):
                yield self._tlist[i]
        else:
            self._tlist += _arange(n, b)
            for i in range(1, n):
                ti = self._tlist[i]
                startindex = (n + i - 1) // i * i
                for j in range(startindex, b, i):
                    self._tlist[j] -= ti
                if i >= a:
                    yield ti

            for i in range(n, b):
                ti = self._tlist[i]
                for j in range(2 * i, b, i):
                    self._tlist[j] -= ti
                if i >= a:
                    yield ti
Ejemplo n.º 12
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def prevprime(n):
    """ Return the largest prime smaller than n.

        Notes
        =====

        Potential primes are located at 6*j +/- 1. This
        property is used during searching.

        >>> from sympy import prevprime
        >>> [(i, prevprime(i)) for i in range(10, 15)]
        [(10, 7), (11, 7), (12, 11), (13, 11), (14, 13)]

        See Also
        ========

        nextprime : Return the ith prime greater than n
        primerange : Generates all primes in a given range
    """
    from sympy.functions.elementary.integers import ceiling

    # wrapping ceiling in int will raise an error if there was a problem
    # determining whether the expression was exactly an integer or not
    n = int(ceiling(n))
    if n < 3:
        raise ValueError("no preceding primes")
    if n < 8:
        return {3: 2, 4: 3, 5: 3, 6: 5, 7: 5}[n]
    if n <= sieve._list[-1]:
        l, u = sieve.search(n)
        if l == u:
            return sieve[l-1]
        else:
            return sieve[l]
    nn = 6*(n//6)
    if n - nn <= 1:
        n = nn - 1
        if isprime(n):
            return n
        n -= 4
    else:
        n = nn + 1
    while 1:
        if isprime(n):
            return n
        n -= 2
        if isprime(n):
            return n
        n -= 4
Ejemplo n.º 13
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 def _eval_aseries(self, n, args0, x, logx):
     from sympy import Order
     if args0[0] != oo:
         return super(loggamma, self)._eval_aseries(n, args0, x, logx)
     z = self.args[0]
     m = min(n, ceiling((n + S(1))/2))
     r = log(z)*(z - S(1)/2) - z + log(2*pi)/2
     l = [bernoulli(2*k) / (2*k*(2*k - 1)*z**(2*k - 1)) for k in range(1, m)]
     o = None
     if m == 0:
         o = Order(1, x)
     else:
         o = Order(1/z**(2*m - 1), x)
     # It is very inefficient to first add the order and then do the nseries
     return (r + Add(*l))._eval_nseries(x, n, logx) + o
Ejemplo n.º 14
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    def __new__(cls, *args):
        from sympy.functions.elementary.integers import ceiling
        if len(args) == 1:
            if isinstance(args[0], range if PY3 else xrange):
                args = args[0].__reduce__()[1]  # use pickle method

        # expand range
        slc = slice(*args)

        if slc.step == 0:
            raise ValueError("step cannot be 0")

        start, stop, step = slc.start or 0, slc.stop, slc.step or 1
        try:
            start, stop, step = [
                w if w in [S.NegativeInfinity, S.Infinity]
                else sympify(as_int(w))
                for w in (start, stop, step)]
        except ValueError:
            raise ValueError(filldedent('''
    Finite arguments to Range must be integers; `imageset` can define
    other cases, e.g. use `imageset(i, i/10, Range(3))` to give
    [0, 1/10, 1/5].'''))

        if not step.is_Integer:
            raise ValueError(filldedent('''
    Ranges must have a literal integer step.'''))

        if all(i.is_infinite for i in  (start, stop)):
            if start == stop:
                # canonical null handled below
                start = stop = S.One
            else:
                raise ValueError(filldedent('''
    Either the start or end value of the Range must be finite.'''))

        if start.is_infinite:
            end = stop
        else:
            ref = start if start.is_finite else stop
            n = ceiling((stop - ref)/step)
            if n <= 0:
                # null Range
                start = end = 0
                step = 1
            else:
                end = ref + n*step
        return Basic.__new__(cls, start, end, step)
Ejemplo n.º 15
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def intersection_sets(a, b):  # noqa:F811
    from sympy.functions.elementary.integers import floor, ceiling
    if not all(i.is_number for i in b.args[:2]):
        return

    # In case of null Range, return an EmptySet.
    if a.size == 0:
        return S.EmptySet

    # trim down to self's size, and represent
    # as a Range with step 1.
    start = ceiling(max(b.inf, a.inf))
    if start not in b:
        start += 1
    end = floor(min(b.sup, a.sup))
    if end not in b:
        end -= 1
    return intersection_sets(a, Range(start, end + 1))
Ejemplo n.º 16
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 def _eval_aseries(self, n, args0, x, logx):
     from sympy import Order
     if args0[0] != oo:
         return super(loggamma, self)._eval_aseries(n, args0, x, logx)
     z = self.args[0]
     m = min(n, ceiling((n + S(1)) / 2))
     r = log(z) * (z - S(1) / 2) - z + log(2 * pi) / 2
     l = [
         bernoulli(2 * k) / (2 * k * (2 * k - 1) * z**(2 * k - 1))
         for k in range(1, m)
     ]
     o = None
     if m == 0:
         o = Order(1, x)
     else:
         o = Order(1 / z**(2 * m - 1), x)
     # It is very inefficient to first add the order and then do the nseries
     return (r + Add(*l))._eval_nseries(x, n, logx) + o
Ejemplo n.º 17
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def _real_to_rational(expr, tolerance=None):
    """
    Replace all reals in expr with rationals.

    >>> from sympy import nsimplify
    >>> from sympy.abc import x

    >>> nsimplify(.76 + .1*x**.5, rational=True)
    sqrt(x)/10 + 19/25

    """
    inf = Float('inf')
    p = expr
    reps = {}
    reduce_num = None
    if tolerance is not None and tolerance < 1:
        reduce_num = ceiling(1/tolerance)
    for float in p.atoms(Float):
        key = float
        if reduce_num is not None:
            r = Rational(float).limit_denominator(reduce_num)
        elif (tolerance is not None and tolerance >= 1 and
                float.is_Integer is False):
            r = Rational(tolerance*round(float/tolerance)
                ).limit_denominator(int(tolerance))
        else:
            r = nsimplify(float, rational=False)
            # e.g. log(3).n() -> log(3) instead of a Rational
            if float and not r:
                r = Rational(float)
            elif not r.is_Rational:
                if float == inf or float == -inf:
                    r = S.ComplexInfinity
                elif float < 0:
                    float = -float
                    d = Pow(10, int((mpmath.log(float)/mpmath.log(10))))
                    r = -Rational(str(float/d))*d
                elif float > 0:
                    d = Pow(10, int((mpmath.log(float)/mpmath.log(10))))
                    r = Rational(str(float/d))*d
                else:
                    r = Integer(0)
        reps[key] = r
    return p.subs(reps, simultaneous=True)
def _real_to_rational(expr, tolerance=None):
    """
    Replace all reals in expr with rationals.

    >>> from sympy import nsimplify
    >>> from sympy.abc import x

    >>> nsimplify(.76 + .1*x**.5, rational=True)
    sqrt(x)/10 + 19/25

    """
    inf = Float('inf')
    p = expr
    reps = {}
    reduce_num = None
    if tolerance is not None and tolerance < 1:
        reduce_num = ceiling(1/tolerance)
    for float in p.atoms(Float):
        key = float
        if reduce_num is not None:
            r = Rational(float).limit_denominator(reduce_num)
        elif (tolerance is not None and tolerance >= 1 and
                float.is_Integer is False):
            r = Rational(tolerance*round(float/tolerance)
                ).limit_denominator(int(tolerance))
        else:
            r = nsimplify(float, rational=False)
            # e.g. log(3).n() -> log(3) instead of a Rational
            if float and not r:
                r = Rational(float)
            elif not r.is_Rational:
                if float == inf or float == -inf:
                    r = S.ComplexInfinity
                elif float < 0:
                    float = -float
                    d = Pow(10, int((mpmath.log(float)/mpmath.log(10))))
                    r = -Rational(str(float/d))*d
                elif float > 0:
                    d = Pow(10, int((mpmath.log(float)/mpmath.log(10))))
                    r = Rational(str(float/d))*d
                else:
                    r = Integer(0)
        reps[key] = r
    return p.subs(reps, simultaneous=True)
Ejemplo n.º 19
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def prevprime(n):
    """ Return the largest prime smaller than n.
        Notes
        =====
        Potential primes are located at 6*j +/- 1. This
        property is used during searching.
        >>> from sympy import prevprime
        >>> [(i, prevprime(i)) for i in range(10, 15)]
        [(10, 7), (11, 7), (12, 11), (13, 11), (14, 13)]
        See Also
        ========
        nextprime : Return the ith prime greater than n
        primerange : Generates all primes in a given range
    """
    from sympy.functions.elementary.integers import ceiling

    # wrapping ceiling in int will raise an error if there was a problem
    # determining whether the expression was exactly an integer or not
    n = int(ceiling(n))
    if n < 3:
        raise ValueError("no preceding primes")
    if n < 8:
        return {3: 2, 4: 3, 5: 3, 6: 5, 7: 5}[n]
    if n <= sieve._list[-1]:
        l, u = sieve.search(n)
        if l == u:
            return sieve[l - 1]
        else:
            return sieve[l]
    nn = 6 * (n // 6)
    if n - nn <= 1:
        n = nn - 1
        if isprime(n):
            return n
        n -= 4
    else:
        n = nn + 1
    while 1:
        if isprime(n):
            return n
        n -= 2
        if isprime(n):
            return n
        n -= 4
Ejemplo n.º 20
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    def __new__(cls, *args):
        # expand range
        slc = slice(*args)
        start, stop, step = slc.start or 0, slc.stop, slc.step or 1
        try:
            start, stop, step = [S(as_int(w)) for w in (start, stop, step)]
        except ValueError:
            raise ValueError("Inputs to Range must be Integer Valued\n" +
                    "Use ImageSets of Ranges for other cases")
        n = ceiling((stop - start)/step)
        if n <= 0:
            return S.EmptySet

        # normalize args: regardless of how they are entered they will show
        # canonically as Range(inf, sup, step) with step > 0
        start, stop = sorted((start, start + (n - 1)*step))
        step = abs(step)

        return Basic.__new__(cls, start, stop + step, step)
Ejemplo n.º 21
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def intersection_sets(a, b):
    from sympy.functions.elementary.integers import floor, ceiling
    from sympy.functions.elementary.miscellaneous import Min, Max
    if not all(i.is_number for i in b.args[:2]):
        return

    # In case of null Range, return an EmptySet.
    if a.size == 0:
        return S.EmptySet

    # trim down to self's size, and represent
    # as a Range with step 1.
    start = ceiling(max(b.inf, a.inf))
    if start not in b:
        start += 1
    end = floor(min(b.sup, a.sup))
    if end not in b:
        end -= 1
    return intersection_sets(a, Range(start, end + 1))
Ejemplo n.º 22
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    def __new__(cls, *args):
        # expand range
        slc = slice(*args)
        start, stop, step = slc.start or 0, slc.stop, slc.step or 1
        try:
            start, stop, step = [S(as_int(w)) for w in (start, stop, step)]
        except ValueError:
            raise ValueError("Inputs to Range must be Integer Valued\n" +
                    "Use TransformationSets of Ranges for other cases")
        n = ceiling((stop - start)/step)
        if n <= 0:
            return S.EmptySet

        # normalize args: regardless of how they are entered they will show
        # canonically as Range(inf, sup, step) with step > 0
        start, stop = sorted((start, start + (n - 1)*step))
        step = abs(step)

        return Basic.__new__(cls, start, stop + step, step)
Ejemplo n.º 23
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 def _eval_nseries(self, x, n, logx, cdir=0):
     # NOTE Please see the comment at the beginning of this file, labelled
     #      IMPORTANT.
     from sympy.functions.elementary.complexes import sign
     from sympy.functions.elementary.integers import ceiling
     from sympy.series.limits import limit
     from sympy.series.order import Order
     from sympy.simplify.powsimp import powsimp
     arg = self.exp
     arg_series = arg._eval_nseries(x, n=n, logx=logx)
     if arg_series.is_Order:
         return 1 + arg_series
     arg0 = limit(arg_series.removeO(), x, 0)
     if arg0 is S.NegativeInfinity:
         return Order(x**n, x)
     if arg0 is S.Infinity:
         return self
     # checking for indecisiveness/ sign terms in arg0
     if any(isinstance(arg, (sign, ImaginaryUnit)) for arg in arg0.args):
         return self
     t = Dummy("t")
     nterms = n
     try:
         cf = Order(arg.as_leading_term(x, logx=logx), x).getn()
     except (NotImplementedError, PoleError):
         cf = 0
     if cf and cf > 0:
         nterms = ceiling(n/cf)
     exp_series = exp(t)._taylor(t, nterms)
     r = exp(arg0)*exp_series.subs(t, arg_series - arg0)
     if cf and cf > 1:
         r += Order((arg_series - arg0)**n, x)/x**((cf-1)*n)
     else:
         r += Order((arg_series - arg0)**n, x)
     r = r.expand()
     r = powsimp(r, deep=True, combine='exp')
     # powsimp may introduce unexpanded (-1)**Rational; see PR #17201
     simplerat = lambda x: x.is_Rational and x.q in [3, 4, 6]
     w = Wild('w', properties=[simplerat])
     r = r.replace(S.NegativeOne**w, expand_complex(S.NegativeOne**w))
     return r
Ejemplo n.º 24
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    def __new__(cls, *args):
        from sympy.functions.elementary.integers import ceiling
        if len(args) == 1:
            if isinstance(args[0], range if PY3 else xrange):
                args = args[0].__reduce__()[1]  # use pickle method

        # expand range
        slc = slice(*args)
        start, stop, step = slc.start or 0, slc.stop, slc.step or 1
        try:
            start, stop, step = [
                w if w in [S.NegativeInfinity, S.Infinity] else sympify(
                    as_int(w)) for w in (start, stop, step)
            ]
        except ValueError:
            raise ValueError("Inputs to Range must be Integer Valued\n" +
                             "Use ImageSets of Ranges for other cases")

        if not step.is_finite:
            raise ValueError("Infinite step is not allowed")
        if start == stop:
            return S.EmptySet

        n = ceiling((stop - start) / step)
        if n <= 0:
            return S.EmptySet

        # normalize args: regardless of how they are entered they will show
        # canonically as Range(inf, sup, step) with step > 0
        if n.is_finite:
            start, stop = sorted((start, start + (n - 1) * step))
        else:
            start, stop = sorted((start, stop - step))

        step = abs(step)
        if (start, stop) == (S.NegativeInfinity, S.Infinity):
            raise ValueError("Both the start and end value of "
                             "Range cannot be unbounded")
        else:
            return Basic.__new__(cls, start, stop + step, step)
Ejemplo n.º 25
0
    def __new__(cls, *args):
        from sympy.functions.elementary.integers import ceiling
        if len(args) == 1:
            if isinstance(args[0], range if PY3 else xrange):
                args = args[0].__reduce__()[1]  # use pickle method

        # expand range
        slc = slice(*args)
        start, stop, step = slc.start or 0, slc.stop, slc.step or 1
        try:
            start, stop, step = [w if w in [S.NegativeInfinity, S.Infinity] else sympify(as_int(w))
                                 for w in (start, stop, step)]
        except ValueError:
            raise ValueError(filldedent('''
    Inputs to Range must be integers;
    use ImageSets of Ranges for other cases, e.g.
    `ImageSet(Lambda(i, i/10), Range(2))` to give [0, .1].'''))

        if not step.is_finite:
            raise ValueError("Infinite step is not allowed")
        if start == stop:
            return S.EmptySet

        n = ceiling((stop - start)/step)
        if n <= 0:
            return S.EmptySet

        # normalize args: regardless of how they are entered they will show
        # canonically as Range(inf, sup, step) with step > 0
        if n.is_finite:
            start, stop = sorted((start, start + (n - 1)*step))
        else:
            start, stop = sorted((start, stop - step))

        step = abs(step)
        if (start, stop) == (S.NegativeInfinity, S.Infinity):
            raise ValueError("Both the start and end value of "
                             "Range cannot be unbounded")
        else:
            return Basic.__new__(cls, start, stop + step, step)
Ejemplo n.º 26
0
def test_evalf_integer_parts():
    a = floor(log(8) / log(2) - exp(-1000), evaluate=False)
    b = floor(log(8) / log(2), evaluate=False)
    assert a.evalf() == 3
    assert b.evalf() == 3
    # equals, as a fallback, can still fail but it might succeed as here
    assert ceiling(10 * (sin(1)**2 + cos(1)**2)) == 10

    assert int(floor(factorial(50)/E, evaluate=False).evalf(70)) == \
        int(11188719610782480504630258070757734324011354208865721592720336800)
    assert int(ceiling(factorial(50)/E, evaluate=False).evalf(70)) == \
        int(11188719610782480504630258070757734324011354208865721592720336801)
    assert int(floor(GoldenRatio**999 / sqrt(5) +
                     S.Half).evalf(1000)) == fibonacci(999)
    assert int(floor(GoldenRatio**1000 / sqrt(5) +
                     S.Half).evalf(1000)) == fibonacci(1000)

    assert ceiling(x).evalf(subs={x: 3}) == 3
    assert ceiling(x).evalf(subs={x: 3 * I}) == 3.0 * I
    assert ceiling(x).evalf(subs={x: 2 + 3 * I}) == 2.0 + 3.0 * I
    assert ceiling(x).evalf(subs={x: 3.}) == 3
    assert ceiling(x).evalf(subs={x: 3. * I}) == 3.0 * I
    assert ceiling(x).evalf(subs={x: 2. + 3 * I}) == 2.0 + 3.0 * I

    assert float((floor(1.5, evaluate=False) + 1 / 9).evalf()) == 1 + 1 / 9
    assert float((floor(0.5, evaluate=False) + 20).evalf()) == 20

    # issue 19991
    n = 1169809367327212570704813632106852886389036911
    r = 744723773141314414542111064094745678855643068

    assert floor(n / (pi / 2)) == r
    assert floor(80782 * sqrt(2)) == 114242

    # issue 20076
    assert 260515 - floor(260515 / pi + 1 / 2) * pi == atan(tan(260515))
Ejemplo n.º 27
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def _initialize_ith_poly(N, factor_base, i, g, B):
    """Initialization stage of ith poly. After we finish sieving 1`st polynomial
    here we quickly change to the next polynomial from which we will again
    start sieving. Suppose we generated ith sieve polynomial and now we
    want to generate (i + 1)th polynomial, where ``1 <= i <= 2**(j - 1) - 1``
    where `j` is the number of prime factors of the coefficient `a`
    then this function can be used to go to the next polynomial. If
    ``i = 2**(j - 1) - 1`` then go to _initialize_first_polynomial stage.

    Parameters
    ==========

    N : number to be factored
    factor_base : factor_base primes
    i : integer denoting ith polynomial
    g : (i - 1)th polynomial
    B : array that stores a//q_l*gamma
    """
    from sympy.functions.elementary.integers import ceiling
    v = 1
    j = i
    while (j % 2 == 0):
        v += 1
        j //= 2
    if ceiling(i / (2**v)) % 2 == 1:
        neg_pow = -1
    else:
        neg_pow = 1
    b = g.b + 2 * neg_pow * B[v - 1]
    a = g.a
    g = SievePolynomial([a * a, 2 * a * b, b * b - N], a, b)
    for fb in factor_base:
        if a % fb.prime == 0:
            continue
        fb.soln1 = (fb.soln1 - neg_pow * fb.b_ainv[v - 1]) % fb.prime
        fb.soln2 = (fb.soln2 - neg_pow * fb.b_ainv[v - 1]) % fb.prime

    return g
Ejemplo n.º 28
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def test_intrinsic_math1_codegen():
    # not included: log10
    from sympy.core.evalf import N
    from sympy.functions import ln
    from sympy.functions.elementary.exponential import log
    from sympy.functions.elementary.hyperbolic import (cosh, sinh, tanh)
    from sympy.functions.elementary.integers import (ceiling, floor)
    from sympy.functions.elementary.miscellaneous import sqrt
    from sympy.functions.elementary.trigonometric import (acos, asin, atan,
                                                          cos, sin, tan)
    name_expr = [
        ("test_fabs", abs(x)),
        ("test_acos", acos(x)),
        ("test_asin", asin(x)),
        ("test_atan", atan(x)),
        ("test_cos", cos(x)),
        ("test_cosh", cosh(x)),
        ("test_log", log(x)),
        ("test_ln", ln(x)),
        ("test_sin", sin(x)),
        ("test_sinh", sinh(x)),
        ("test_sqrt", sqrt(x)),
        ("test_tan", tan(x)),
        ("test_tanh", tanh(x)),
    ]
    numerical_tests = []
    for name, expr in name_expr:
        for xval in 0.2, 0.5, 0.8:
            expected = N(expr.subs(x, xval))
            numerical_tests.append((name, (xval, ), expected, 1e-14))
    for lang, commands in valid_lang_commands:
        if lang.startswith("C"):
            name_expr_C = [("test_floor", floor(x)), ("test_ceil", ceiling(x))]
        else:
            name_expr_C = []
        run_test("intrinsic_math1", name_expr + name_expr_C, numerical_tests,
                 lang, commands)
Ejemplo n.º 29
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def test_nested_floor_ceiling():
    assert floor(-floor(ceiling(x**3)/y)) == -floor(ceiling(x**3)/y)
    assert ceiling(-floor(ceiling(x**3)/y)) == -floor(ceiling(x**3)/y)
    assert floor(ceiling(-floor(x**Rational(7, 2)/y))) == -floor(x**Rational(7, 2)/y)
    assert -ceiling(-ceiling(floor(x)/y)) == ceiling(floor(x)/y)
Ejemplo n.º 30
0
def test_issue_10323():
    assert ceiling(sqrt(2**30 + 1)) == 2**15 + 1
Ejemplo n.º 31
0
def test_sympy__functions__elementary__integers__ceiling():
    from sympy.functions.elementary.integers import ceiling
    assert _test_args(ceiling(x))
Ejemplo n.º 32
0
def test_floor():

    assert floor(nan) is nan

    assert floor(oo) is oo
    assert floor(-oo) is -oo
    assert floor(zoo) is zoo

    assert floor(0) == 0

    assert floor(1) == 1
    assert floor(-1) == -1

    assert floor(E) == 2
    assert floor(-E) == -3

    assert floor(2*E) == 5
    assert floor(-2*E) == -6

    assert floor(pi) == 3
    assert floor(-pi) == -4

    assert floor(S.Half) == 0
    assert floor(Rational(-1, 2)) == -1

    assert floor(Rational(7, 3)) == 2
    assert floor(Rational(-7, 3)) == -3
    assert floor(-Rational(7, 3)) == -3

    assert floor(Float(17.0)) == 17
    assert floor(-Float(17.0)) == -17

    assert floor(Float(7.69)) == 7
    assert floor(-Float(7.69)) == -8

    assert floor(I) == I
    assert floor(-I) == -I
    e = floor(i)
    assert e.func is floor and e.args[0] == i

    assert floor(oo*I) == oo*I
    assert floor(-oo*I) == -oo*I
    assert floor(exp(I*pi/4)*oo) == exp(I*pi/4)*oo

    assert floor(2*I) == 2*I
    assert floor(-2*I) == -2*I

    assert floor(I/2) == 0
    assert floor(-I/2) == -I

    assert floor(E + 17) == 19
    assert floor(pi + 2) == 5

    assert floor(E + pi) == 5
    assert floor(I + pi) == 3 + I

    assert floor(floor(pi)) == 3
    assert floor(floor(y)) == floor(y)
    assert floor(floor(x)) == floor(x)

    assert unchanged(floor, x)
    assert unchanged(floor, 2*x)
    assert unchanged(floor, k*x)

    assert floor(k) == k
    assert floor(2*k) == 2*k
    assert floor(k*n) == k*n

    assert unchanged(floor, k/2)

    assert unchanged(floor, x + y)

    assert floor(x + 3) == floor(x) + 3
    assert floor(x + k) == floor(x) + k

    assert floor(y + 3) == floor(y) + 3
    assert floor(y + k) == floor(y) + k

    assert floor(3 + I*y + pi) == 6 + floor(y)*I

    assert floor(k + n) == k + n

    assert unchanged(floor, x*I)
    assert floor(k*I) == k*I

    assert floor(Rational(23, 10) - E*I) == 2 - 3*I

    assert floor(sin(1)) == 0
    assert floor(sin(-1)) == -1

    assert floor(exp(2)) == 7

    assert floor(log(8)/log(2)) != 2
    assert int(floor(log(8)/log(2)).evalf(chop=True)) == 3

    assert floor(factorial(50)/exp(1)) == \
        11188719610782480504630258070757734324011354208865721592720336800

    assert (floor(y) < y) == False
    assert (floor(y) <= y) == True
    assert (floor(y) > y) == False
    assert (floor(y) >= y) == False
    assert (floor(x) <= x).is_Relational  # x could be non-real
    assert (floor(x) > x).is_Relational
    assert (floor(x) <= y).is_Relational  # arg is not same as rhs
    assert (floor(x) > y).is_Relational
    assert (floor(y) <= oo) == True
    assert (floor(y) < oo) == True
    assert (floor(y) >= -oo) == True
    assert (floor(y) > -oo) == True

    assert floor(y).rewrite(frac) == y - frac(y)
    assert floor(y).rewrite(ceiling) == -ceiling(-y)
    assert floor(y).rewrite(frac).subs(y, -pi) == floor(-pi)
    assert floor(y).rewrite(frac).subs(y, E) == floor(E)
    assert floor(y).rewrite(ceiling).subs(y, E) == -ceiling(-E)
    assert floor(y).rewrite(ceiling).subs(y, -pi) == -ceiling(pi)

    assert Eq(floor(y), y - frac(y))
    assert Eq(floor(y), -ceiling(-y))

    neg = Symbol('neg', negative=True)
    nn = Symbol('nn', nonnegative=True)
    pos = Symbol('pos', positive=True)
    np = Symbol('np', nonpositive=True)

    assert (floor(neg) < 0) == True
    assert (floor(neg) <= 0) == True
    assert (floor(neg) > 0) == False
    assert (floor(neg) >= 0) == False
    assert (floor(neg) <= -1) == True
    assert (floor(neg) >= -3) == (neg >= -3)
    assert (floor(neg) < 5) == (neg < 5)

    assert (floor(nn) < 0) == False
    assert (floor(nn) >= 0) == True

    assert (floor(pos) < 0) == False
    assert (floor(pos) <= 0) == (pos < 1)
    assert (floor(pos) > 0) == (pos >= 1)
    assert (floor(pos) >= 0) == True
    assert (floor(pos) >= 3) == (pos >= 3)

    assert (floor(np) <= 0) == True
    assert (floor(np) > 0) == False

    assert floor(neg).is_negative == True
    assert floor(neg).is_nonnegative == False
    assert floor(nn).is_negative == False
    assert floor(nn).is_nonnegative == True
    assert floor(pos).is_negative == False
    assert floor(pos).is_nonnegative == True
    assert floor(np).is_negative is None
    assert floor(np).is_nonnegative is None

    assert (floor(7, evaluate=False) >= 7) == True
    assert (floor(7, evaluate=False) > 7) == False
    assert (floor(7, evaluate=False) <= 7) == True
    assert (floor(7, evaluate=False) < 7) == False

    assert (floor(7, evaluate=False) >= 6) == True
    assert (floor(7, evaluate=False) > 6) == True
    assert (floor(7, evaluate=False) <= 6) == False
    assert (floor(7, evaluate=False) < 6) == False

    assert (floor(7, evaluate=False) >= 8) == False
    assert (floor(7, evaluate=False) > 8) == False
    assert (floor(7, evaluate=False) <= 8) == True
    assert (floor(7, evaluate=False) < 8) == True

    assert (floor(x) <= 5.5) == Le(floor(x), 5.5, evaluate=False)
    assert (floor(x) >= -3.2) == Ge(floor(x), -3.2, evaluate=False)
    assert (floor(x) < 2.9) == Lt(floor(x), 2.9, evaluate=False)
    assert (floor(x) > -1.7) == Gt(floor(x), -1.7, evaluate=False)

    assert (floor(y) <= 5.5) == (y < 6)
    assert (floor(y) >= -3.2) == (y >= -3)
    assert (floor(y) < 2.9) == (y < 3)
    assert (floor(y) > -1.7) == (y >= -1)

    assert (floor(y) <= n) == (y < n + 1)
    assert (floor(y) >= n) == (y >= n)
    assert (floor(y) < n) == (y < n)
    assert (floor(y) > n) == (y >= n + 1)
Ejemplo n.º 33
0
def test_frac():
    assert isinstance(frac(x), frac)
    assert frac(oo) == AccumBounds(0, 1)
    assert frac(-oo) == AccumBounds(0, 1)
    assert frac(zoo) is nan

    assert frac(n) == 0
    assert frac(nan) is nan
    assert frac(Rational(4, 3)) == Rational(1, 3)
    assert frac(-Rational(4, 3)) == Rational(2, 3)
    assert frac(Rational(-4, 3)) == Rational(2, 3)

    r = Symbol('r', real=True)
    assert frac(I*r) == I*frac(r)
    assert frac(1 + I*r) == I*frac(r)
    assert frac(0.5 + I*r) == 0.5 + I*frac(r)
    assert frac(n + I*r) == I*frac(r)
    assert frac(n + I*k) == 0
    assert unchanged(frac, x + I*x)
    assert frac(x + I*n) == frac(x)

    assert frac(x).rewrite(floor) == x - floor(x)
    assert frac(x).rewrite(ceiling) == x + ceiling(-x)
    assert frac(y).rewrite(floor).subs(y, pi) == frac(pi)
    assert frac(y).rewrite(floor).subs(y, -E) == frac(-E)
    assert frac(y).rewrite(ceiling).subs(y, -pi) == frac(-pi)
    assert frac(y).rewrite(ceiling).subs(y, E) == frac(E)

    assert Eq(frac(y), y - floor(y))
    assert Eq(frac(y), y + ceiling(-y))

    r = Symbol('r', real=True)
    p_i = Symbol('p_i', integer=True, positive=True)
    n_i = Symbol('p_i', integer=True, negative=True)
    np_i = Symbol('np_i', integer=True, nonpositive=True)
    nn_i = Symbol('nn_i', integer=True, nonnegative=True)
    p_r = Symbol('p_r', positive=True)
    n_r = Symbol('n_r', negative=True)
    np_r = Symbol('np_r', real=True, nonpositive=True)
    nn_r = Symbol('nn_r', real=True, nonnegative=True)

    # Real frac argument, integer rhs
    assert frac(r) <= p_i
    assert not frac(r) <= n_i
    assert (frac(r) <= np_i).has(Le)
    assert (frac(r) <= nn_i).has(Le)
    assert frac(r) < p_i
    assert not frac(r) < n_i
    assert not frac(r) < np_i
    assert (frac(r) < nn_i).has(Lt)
    assert not frac(r) >= p_i
    assert frac(r) >= n_i
    assert frac(r) >= np_i
    assert (frac(r) >= nn_i).has(Ge)
    assert not frac(r) > p_i
    assert frac(r) > n_i
    assert (frac(r) > np_i).has(Gt)
    assert (frac(r) > nn_i).has(Gt)

    assert not Eq(frac(r), p_i)
    assert not Eq(frac(r), n_i)
    assert Eq(frac(r), np_i).has(Eq)
    assert Eq(frac(r), nn_i).has(Eq)

    assert Ne(frac(r), p_i)
    assert Ne(frac(r), n_i)
    assert Ne(frac(r), np_i).has(Ne)
    assert Ne(frac(r), nn_i).has(Ne)


    # Real frac argument, real rhs
    assert (frac(r) <= p_r).has(Le)
    assert not frac(r) <= n_r
    assert (frac(r) <= np_r).has(Le)
    assert (frac(r) <= nn_r).has(Le)
    assert (frac(r) < p_r).has(Lt)
    assert not frac(r) < n_r
    assert not frac(r) < np_r
    assert (frac(r) < nn_r).has(Lt)
    assert (frac(r) >= p_r).has(Ge)
    assert frac(r) >= n_r
    assert frac(r) >= np_r
    assert (frac(r) >= nn_r).has(Ge)
    assert (frac(r) > p_r).has(Gt)
    assert frac(r) > n_r
    assert (frac(r) > np_r).has(Gt)
    assert (frac(r) > nn_r).has(Gt)

    assert not Eq(frac(r), n_r)
    assert Eq(frac(r), p_r).has(Eq)
    assert Eq(frac(r), np_r).has(Eq)
    assert Eq(frac(r), nn_r).has(Eq)

    assert Ne(frac(r), p_r).has(Ne)
    assert Ne(frac(r), n_r)
    assert Ne(frac(r), np_r).has(Ne)
    assert Ne(frac(r), nn_r).has(Ne)

    # Real frac argument, +/- oo rhs
    assert frac(r) < oo
    assert frac(r) <= oo
    assert not frac(r) > oo
    assert not frac(r) >= oo

    assert not frac(r) < -oo
    assert not frac(r) <= -oo
    assert frac(r) > -oo
    assert frac(r) >= -oo

    assert frac(r) < 1
    assert frac(r) <= 1
    assert not frac(r) > 1
    assert not frac(r) >= 1

    assert not frac(r) < 0
    assert (frac(r) <= 0).has(Le)
    assert (frac(r) > 0).has(Gt)
    assert frac(r) >= 0

    # Some test for numbers
    assert frac(r) <= sqrt(2)
    assert (frac(r) <= sqrt(3) - sqrt(2)).has(Le)
    assert not frac(r) <= sqrt(2) - sqrt(3)
    assert not frac(r) >= sqrt(2)
    assert (frac(r) >= sqrt(3) - sqrt(2)).has(Ge)
    assert frac(r) >= sqrt(2) - sqrt(3)

    assert not Eq(frac(r), sqrt(2))
    assert Eq(frac(r), sqrt(3) - sqrt(2)).has(Eq)
    assert not Eq(frac(r), sqrt(2) - sqrt(3))
    assert Ne(frac(r), sqrt(2))
    assert Ne(frac(r), sqrt(3) - sqrt(2)).has(Ne)
    assert Ne(frac(r), sqrt(2) - sqrt(3))

    assert frac(p_i, evaluate=False).is_zero
    assert frac(p_i, evaluate=False).is_finite
    assert frac(p_i, evaluate=False).is_integer
    assert frac(p_i, evaluate=False).is_real
    assert frac(r).is_finite
    assert frac(r).is_real
    assert frac(r).is_zero is None
    assert frac(r).is_integer is None

    assert frac(oo).is_finite
    assert frac(oo).is_real
Ejemplo n.º 34
0
 def __getitem__(self, i):
     ooslice = "cannot slice from the end with an infinite value"
     zerostep = "slice step cannot be zero"
     infinite = "slicing not possible on range with infinite start"
     # if we had to take every other element in the following
     # oo, ..., 6, 4, 2, 0
     # we might get oo, ..., 4, 0 or oo, ..., 6, 2
     ambiguous = "cannot unambiguously re-stride from the end " + \
         "with an infinite value"
     if isinstance(i, slice):
         if self.size.is_finite:  # validates, too
             if self.start == self.stop:
                 return Range(0)
             start, stop, step = i.indices(self.size)
             n = ceiling((stop - start) / step)
             if n <= 0:
                 return Range(0)
             canonical_stop = start + n * step
             end = canonical_stop - step
             ss = step * self.step
             return Range(self[start], self[end] + ss, ss)
         else:  # infinite Range
             start = i.start
             stop = i.stop
             if i.step == 0:
                 raise ValueError(zerostep)
             step = i.step or 1
             ss = step * self.step
             #---------------------
             # handle infinite Range
             #   i.e. Range(-oo, oo) or Range(oo, -oo, -1)
             # --------------------
             if self.start.is_infinite and self.stop.is_infinite:
                 raise ValueError(infinite)
             #---------------------
             # handle infinite on right
             #   e.g. Range(0, oo) or Range(0, -oo, -1)
             # --------------------
             if self.stop.is_infinite:
                 # start and stop are not interdependent --
                 # they only depend on step --so we use the
                 # equivalent reversed values
                 return self.reversed[
                     stop if stop is None else -stop +
                     1:start if start is None else -start:step].reversed
             #---------------------
             # handle infinite on the left
             #   e.g. Range(oo, 0, -1) or Range(-oo, 0)
             # --------------------
             # consider combinations of
             # start/stop {== None, < 0, == 0, > 0} and
             # step {< 0, > 0}
             if start is None:
                 if stop is None:
                     if step < 0:
                         return Range(self[-1], self.start, ss)
                     elif step > 1:
                         raise ValueError(ambiguous)
                     else:  # == 1
                         return self
                 elif stop < 0:
                     if step < 0:
                         return Range(self[-1], self[stop], ss)
                     else:  # > 0
                         return Range(self.start, self[stop], ss)
                 elif stop == 0:
                     if step > 0:
                         return Range(0)
                     else:  # < 0
                         raise ValueError(ooslice)
                 elif stop == 1:
                     if step > 0:
                         raise ValueError(ooslice)  # infinite singleton
                     else:  # < 0
                         raise ValueError(ooslice)
                 else:  # > 1
                     raise ValueError(ooslice)
             elif start < 0:
                 if stop is None:
                     if step < 0:
                         return Range(self[start], self.start, ss)
                     else:  # > 0
                         return Range(self[start], self.stop, ss)
                 elif stop < 0:
                     return Range(self[start], self[stop], ss)
                 elif stop == 0:
                     if step < 0:
                         raise ValueError(ooslice)
                     else:  # > 0
                         return Range(0)
                 elif stop > 0:
                     raise ValueError(ooslice)
             elif start == 0:
                 if stop is None:
                     if step < 0:
                         raise ValueError(ooslice)  # infinite singleton
                     elif step > 1:
                         raise ValueError(ambiguous)
                     else:  # == 1
                         return self
                 elif stop < 0:
                     if step > 1:
                         raise ValueError(ambiguous)
                     elif step == 1:
                         return Range(self.start, self[stop], ss)
                     else:  # < 0
                         return Range(0)
                 else:  # >= 0
                     raise ValueError(ooslice)
             elif start > 0:
                 raise ValueError(ooslice)
     else:
         if self.start == self.stop:
             raise IndexError('Range index out of range')
         if not (all(i.is_integer or i.is_infinite for i in self.args) and (
             (self.stop - self.start) / self.step).is_extended_positive):
             raise ValueError('Invalid method for symbolic Range')
         if i == 0:
             if self.start.is_infinite:
                 raise ValueError(ooslice)
             return self.start
         if i == -1:
             if self.stop.is_infinite:
                 raise ValueError(ooslice)
             return self.stop - self.step
         n = self.size  # must be known for any other index
         rv = (self.stop if i < 0 else self.start) + i * self.step
         if rv.is_infinite:
             raise ValueError(ooslice)
         val = (rv - self.start) / self.step
         rel = fuzzy_or([
             val.is_infinite,
             fuzzy_and([val.is_nonnegative, (n - val).is_nonnegative])
         ])
         if rel:
             return rv
         if rel is None:
             raise ValueError('Invalid method for symbolic Range')
         raise IndexError("Range index out of range")
Ejemplo n.º 35
0
 def _intersect(self, other):
     if other.is_Interval:
         s = FiniteSet(range(ceiling(other.left), floor(other.right) + 1))
         return s.intersect(other) # take out endpoints if open interval
     return None
Ejemplo n.º 36
0
def _real_to_rational(expr, tolerance=None, rational_conversion='base10'):
    """
    Replace all reals in expr with rationals.

    >>> from sympy import Rational
    >>> from sympy.simplify.simplify import _real_to_rational
    >>> from sympy.abc import x

    >>> _real_to_rational(.76 + .1*x**.5)
    sqrt(x)/10 + 19/25

    If rational_conversion='base10', this uses the base-10 string. If
    rational_conversion='exact', the exact, base-2 representation is used.

    >>> _real_to_rational(0.333333333333333, rational_conversion='exact')
    6004799503160655/18014398509481984
    >>> _real_to_rational(0.333333333333333)
    1/3

    """
    expr = _sympify(expr)
    inf = Float('inf')
    p = expr
    reps = {}
    reduce_num = None
    if tolerance is not None and tolerance < 1:
        reduce_num = ceiling(1/tolerance)
    for fl in p.atoms(Float):
        key = fl
        if reduce_num is not None:
            r = Rational(fl).limit_denominator(reduce_num)
        elif (tolerance is not None and tolerance >= 1 and
                fl.is_Integer is False):
            r = Rational(tolerance*round(fl/tolerance)
                ).limit_denominator(int(tolerance))
        else:
            if rational_conversion == 'exact':
                r = Rational(fl)
                reps[key] = r
                continue
            elif rational_conversion != 'base10':
                raise ValueError("rational_conversion must be 'base10' or 'exact'")

            r = nsimplify(fl, rational=False)
            # e.g. log(3).n() -> log(3) instead of a Rational
            if fl and not r:
                r = Rational(fl)
            elif not r.is_Rational:
                if fl == inf or fl == -inf:
                    r = S.ComplexInfinity
                elif fl < 0:
                    fl = -fl
                    d = Pow(10, int((mpmath.log(fl)/mpmath.log(10))))
                    r = -Rational(str(fl/d))*d
                elif fl > 0:
                    d = Pow(10, int((mpmath.log(fl)/mpmath.log(10))))
                    r = Rational(str(fl/d))*d
                else:
                    r = Integer(0)
        reps[key] = r
    return p.subs(reps, simultaneous=True)
Ejemplo n.º 37
0
def rsolve_hypergeometric(f, x, P, Q, k, m):
    """Solves RE of hypergeometric type.

    Attempts to solve RE of the form

    Q(k)*a(k + m) - P(k)*a(k)

    Transformations that preserve Hypergeometric type:

        a. x**n*f(x): b(k + m) = R(k - n)*b(k)
        b. f(A*x): b(k + m) = A**m*R(k)*b(k)
        c. f(x**n): b(k + n*m) = R(k/n)*b(k)
        d. f(x**(1/m)): b(k + 1) = R(k*m)*b(k)
        e. f'(x): b(k + m) = ((k + m + 1)/(k + 1))*R(k + 1)*b(k)

    Some of these transformations have been used to solve the RE.

    Returns
    =======

    formula : Expr
    ind : Expr
        Independent terms.
    order : int

    Examples
    ========

    >>> from sympy import exp, ln, S
    >>> from sympy.series.formal import rsolve_hypergeometric as rh
    >>> from sympy.abc import x, k

    >>> rh(exp(x), x, -S.One, (k + 1), k, 1)
    (Piecewise((1/factorial(k), Eq(Mod(k, 1), 0)), (0, True)), 1, 1)

    >>> rh(ln(1 + x), x, k**2, k*(k + 1), k, 1)
    (Piecewise(((-1)**(k - 1)*factorial(k - 1)/RisingFactorial(2, k - 1),
     Eq(Mod(k, 1), 0)), (0, True)), x, 2)

    References
    ==========

    .. [1] Formal Power Series - Dominik Gruntz, Wolfram Koepf
    .. [2] Power Series in Computer Algebra - Wolfram Koepf
    """
    result = _rsolve_hypergeometric(f, x, P, Q, k, m)

    if result is None:
        return None

    sol_list, ind, mp = result

    sol_dict = defaultdict(lambda: S.Zero)
    for res, cond in sol_list:
        j, mk = cond.as_coeff_Add()
        c = mk.coeff(k)

        if j.is_integer is False:
            res *= x**frac(j)
            j = floor(j)

        res = res.subs(k, (k - j) / c)
        cond = Eq(k % c, j % c)
        sol_dict[cond] += res  # Group together formula for same conditions

    sol = []
    for cond, res in sol_dict.items():
        sol.append((res, cond))
    sol.append((S.Zero, True))
    sol = Piecewise(*sol)

    if mp is -oo:
        s = S.Zero
    elif mp.is_integer is False:
        s = ceiling(mp)
    else:
        s = mp + 1

    #  save all the terms of
    #  form 1/x**k in ind
    if s < 0:
        ind += sum(sequence(sol * x**k, (k, s, -1)))
        s = S.Zero

    return (sol, ind, s)
Ejemplo n.º 38
0
def _real_to_rational(expr, tolerance=None, rational_conversion='base10'):
    """
    Replace all reals in expr with rationals.

    >>> from sympy import Rational
    >>> from sympy.simplify.simplify import _real_to_rational
    >>> from sympy.abc import x

    >>> _real_to_rational(.76 + .1*x**.5)
    sqrt(x)/10 + 19/25

    If rational_conversion='base10', this uses the base-10 string. If
    rational_conversion='exact', the exact, base-2 representation is used.

    >>> _real_to_rational(0.333333333333333, rational_conversion='exact')
    6004799503160655/18014398509481984
    >>> _real_to_rational(0.333333333333333)
    1/3

    """
    expr = _sympify(expr)
    inf = Float('inf')
    p = expr
    reps = {}
    reduce_num = None
    if tolerance is not None and tolerance < 1:
        reduce_num = ceiling(1/tolerance)
    for fl in p.atoms(Float):
        key = fl
        if reduce_num is not None:
            r = Rational(fl).limit_denominator(reduce_num)
        elif (tolerance is not None and tolerance >= 1 and
                fl.is_Integer is False):
            r = Rational(tolerance*round(fl/tolerance)
                ).limit_denominator(int(tolerance))
        else:
            if rational_conversion == 'exact':
                r = Rational(fl)
                reps[key] = r
                continue
            elif rational_conversion != 'base10':
                raise ValueError("rational_conversion must be 'base10' or 'exact'")

            r = nsimplify(fl, rational=False)
            # e.g. log(3).n() -> log(3) instead of a Rational
            if fl and not r:
                r = Rational(fl)
            elif not r.is_Rational:
                if fl == inf or fl == -inf:
                    r = S.ComplexInfinity
                elif fl < 0:
                    fl = -fl
                    d = Pow(10, int((mpmath.log(fl)/mpmath.log(10))))
                    r = -Rational(str(fl/d))*d
                elif fl > 0:
                    d = Pow(10, int((mpmath.log(fl)/mpmath.log(10))))
                    r = Rational(str(fl/d))*d
                else:
                    r = Integer(0)
        reps[key] = r
    return p.subs(reps, simultaneous=True)
Ejemplo n.º 39
0
    def __new__(cls, *args):
        from sympy.functions.elementary.integers import ceiling
        if len(args) == 1:
            if isinstance(args[0], range):
                raise TypeError('use sympify(%s) to convert range to Range' %
                                args[0])

        # expand range
        slc = slice(*args)

        if slc.step == 0:
            raise ValueError("step cannot be 0")

        start, stop, step = slc.start or 0, slc.stop, slc.step or 1
        try:
            ok = []
            for w in (start, stop, step):
                w = sympify(w)
                if w in [S.NegativeInfinity, S.Infinity
                         ] or (w.has(Symbol) and w.is_integer != False):
                    ok.append(w)
                elif not w.is_Integer:
                    raise ValueError
                else:
                    ok.append(w)
        except ValueError:
            raise ValueError(
                filldedent('''
    Finite arguments to Range must be integers; `imageset` can define
    other cases, e.g. use `imageset(i, i/10, Range(3))` to give
    [0, 1/10, 1/5].'''))
        start, stop, step = ok

        null = False
        if any(i.has(Symbol) for i in (start, stop, step)):
            if start == stop:
                null = True
            else:
                end = stop
        elif start.is_infinite:
            span = step * (stop - start)
            if span is S.NaN or span <= 0:
                null = True
            elif step.is_Integer and stop.is_infinite and abs(step) != 1:
                raise ValueError(
                    filldedent('''
                    Step size must be %s in this case.''' %
                               (1 if step > 0 else -1)))
            else:
                end = stop
        else:
            oostep = step.is_infinite
            if oostep:
                step = S.One if step > 0 else S.NegativeOne
            n = ceiling((stop - start) / step)
            if n <= 0:
                null = True
            elif oostep:
                end = start + 1
                step = S.One  # make it a canonical single step
            else:
                end = start + n * step
        if null:
            start = end = S.Zero
            step = S.One
        return Basic.__new__(cls, start, end, step)
Ejemplo n.º 40
0
def test_ceiling():
    assert limit(ceiling(x), x, -2, "+") == -1
    assert limit(ceiling(x), x, -2, "-") == -2
    assert limit(ceiling(x), x, -1, "+") == 0
    assert limit(ceiling(x), x, -1, "-") == -1
    assert limit(ceiling(x), x, 0, "+") == 1
    assert limit(ceiling(x), x, 0, "-") == 0
    assert limit(ceiling(x), x, 1, "+") == 2
    assert limit(ceiling(x), x, 1, "-") == 1
    assert limit(ceiling(x), x, 2, "+") == 3
    assert limit(ceiling(x), x, 2, "-") == 2
    assert limit(ceiling(x), x, 248, "+") == 249
    assert limit(ceiling(x), x, 248, "-") == 248

    # https://github.com/sympy/sympy/issues/14478
    assert limit(x*ceiling(3/x)/2, x, 0, '+') == Rational(3, 2)
    assert limit(ceiling(x + 1/2) - ceiling(x), x, oo) == AccumBounds(-S.Half, S(3)/2)
Ejemplo n.º 41
0
def test_sympy__functions__elementary__integers__ceiling():
    from sympy.functions.elementary.integers import ceiling
    assert _test_args(ceiling(x))
Ejemplo n.º 42
0
 def _intersect(self, other):
     if other.is_Interval and other.measure < oo:
         s = Range(ceiling(other.left), floor(other.right) + 1)
         return s.intersect(other)  # take out endpoints if open interval
     return None
Ejemplo n.º 43
0
    def _intersect(self, other):
        from sympy.functions.elementary.integers import ceiling, floor
        from sympy.functions.elementary.complexes import sign

        if other is S.Naturals:
            return self._intersect(Interval(1, S.Infinity))

        if other is S.Integers:
            return self

        if other.is_Interval:
            if not all(i.is_number for i in other.args[:2]):
                return

            # In case of null Range, return an EmptySet.
            if self.size == 0:
                return S.EmptySet

            # trim down to self's size, and represent
            # as a Range with step 1.
            start = ceiling(max(other.inf, self.inf))
            if start not in other:
                start += 1
            end = floor(min(other.sup, self.sup))
            if end not in other:
                end -= 1
            return self.intersect(Range(start, end + 1))

        if isinstance(other, Range):
            from sympy.solvers.diophantine import diop_linear
            from sympy.core.numbers import ilcm

            # non-overlap quick exits
            if not other:
                return S.EmptySet
            if not self:
                return S.EmptySet
            if other.sup < self.inf:
                return S.EmptySet
            if other.inf > self.sup:
                return S.EmptySet

            # work with finite end at the start
            r1 = self
            if r1.start.is_infinite:
                r1 = r1.reversed
            r2 = other
            if r2.start.is_infinite:
                r2 = r2.reversed

            # this equation represents the values of the Range;
            # it's a linear equation
            eq = lambda r, i: r.start + i * r.step

            # we want to know when the two equations might
            # have integer solutions so we use the diophantine
            # solver
            a, b = diop_linear(eq(r1, Dummy()) - eq(r2, Dummy()))

            # check for no solution
            no_solution = a is None and b is None
            if no_solution:
                return S.EmptySet

            # there is a solution
            # -------------------

            # find the coincident point, c
            a0 = a.as_coeff_Add()[0]
            c = eq(r1, a0)

            # find the first point, if possible, in each range
            # since c may not be that point
            def _first_finite_point(r1, c):
                if c == r1.start:
                    return c
                # st is the signed step we need to take to
                # get from c to r1.start
                st = sign(r1.start - c) * step
                # use Range to calculate the first point:
                # we want to get as close as possible to
                # r1.start; the Range will not be null since
                # it will at least contain c
                s1 = Range(c, r1.start + st, st)[-1]
                if s1 == r1.start:
                    pass
                else:
                    # if we didn't hit r1.start then, if the
                    # sign of st didn't match the sign of r1.step
                    # we are off by one and s1 is not in r1
                    if sign(r1.step) != sign(st):
                        s1 -= st
                if s1 not in r1:
                    return
                return s1

            # calculate the step size of the new Range
            step = abs(ilcm(r1.step, r2.step))
            s1 = _first_finite_point(r1, c)
            if s1 is None:
                return S.EmptySet
            s2 = _first_finite_point(r2, c)
            if s2 is None:
                return S.EmptySet

            # replace the corresponding start or stop in
            # the original Ranges with these points; the
            # result must have at least one point since
            # we know that s1 and s2 are in the Ranges
            def _updated_range(r, first):
                st = sign(r.step) * step
                if r.start.is_finite:
                    rv = Range(first, r.stop, st)
                else:
                    rv = Range(r.start, first + st, st)
                return rv

            r1 = _updated_range(self, s1)
            r2 = _updated_range(other, s2)

            # work with them both in the increasing direction
            if sign(r1.step) < 0:
                r1 = r1.reversed
            if sign(r2.step) < 0:
                r2 = r2.reversed

            # return clipped Range with positive step; it
            # can't be empty at this point
            start = max(r1.start, r2.start)
            stop = min(r1.stop, r2.stop)
            return Range(start, stop, step)
        else:
            return
Ejemplo n.º 44
0
def test_issue_18421():
    assert floor(float(0)) is S.Zero
    assert ceiling(float(0)) is S.Zero
Ejemplo n.º 45
0
 def __getitem__(self, i):
     from sympy.functions.elementary.integers import ceiling
     ooslice = "cannot slice from the end with an infinite value"
     zerostep = "slice step cannot be zero"
     # if we had to take every other element in the following
     # oo, ..., 6, 4, 2, 0
     # we might get oo, ..., 4, 0 or oo, ..., 6, 2
     ambiguous = "cannot unambiguously re-stride from the end " + \
         "with an infinite value"
     if isinstance(i, slice):
         if self.size.is_finite:
             start, stop, step = i.indices(self.size)
             n = ceiling((stop - start) / step)
             if n <= 0:
                 return Range(0)
             canonical_stop = start + n * step
             end = canonical_stop - step
             ss = step * self.step
             return Range(self[start], self[end] + ss, ss)
         else:  # infinite Range
             start = i.start
             stop = i.stop
             if i.step == 0:
                 raise ValueError(zerostep)
             step = i.step or 1
             ss = step * self.step
             #---------------------
             # handle infinite on right
             #   e.g. Range(0, oo) or Range(0, -oo, -1)
             # --------------------
             if self.stop.is_infinite:
                 # start and stop are not interdependent --
                 # they only depend on step --so we use the
                 # equivalent reversed values
                 return self.reversed[
                     stop if stop is None else -stop +
                     1:start if start is None else -start:step].reversed
             #---------------------
             # handle infinite on the left
             #   e.g. Range(oo, 0, -1) or Range(-oo, 0)
             # --------------------
             # consider combinations of
             # start/stop {== None, < 0, == 0, > 0} and
             # step {< 0, > 0}
             if start is None:
                 if stop is None:
                     if step < 0:
                         return Range(self[-1], self.start, ss)
                     elif step > 1:
                         raise ValueError(ambiguous)
                     else:  # == 1
                         return self
                 elif stop < 0:
                     if step < 0:
                         return Range(self[-1], self[stop], ss)
                     else:  # > 0
                         return Range(self.start, self[stop], ss)
                 elif stop == 0:
                     if step > 0:
                         return Range(0)
                     else:  # < 0
                         raise ValueError(ooslice)
                 elif stop == 1:
                     if step > 0:
                         raise ValueError(ooslice)  # infinite singleton
                     else:  # < 0
                         raise ValueError(ooslice)
                 else:  # > 1
                     raise ValueError(ooslice)
             elif start < 0:
                 if stop is None:
                     if step < 0:
                         return Range(self[start], self.start, ss)
                     else:  # > 0
                         return Range(self[start], self.stop, ss)
                 elif stop < 0:
                     return Range(self[start], self[stop], ss)
                 elif stop == 0:
                     if step < 0:
                         raise ValueError(ooslice)
                     else:  # > 0
                         return Range(0)
                 elif stop > 0:
                     raise ValueError(ooslice)
             elif start == 0:
                 if stop is None:
                     if step < 0:
                         raise ValueError(ooslice)  # infinite singleton
                     elif step > 1:
                         raise ValueError(ambiguous)
                     else:  # == 1
                         return self
                 elif stop < 0:
                     if step > 1:
                         raise ValueError(ambiguous)
                     elif step == 1:
                         return Range(self.start, self[stop], ss)
                     else:  # < 0
                         return Range(0)
                 else:  # >= 0
                     raise ValueError(ooslice)
             elif start > 0:
                 raise ValueError(ooslice)
     else:
         if not self:
             raise IndexError('Range index out of range')
         if i == 0:
             return self.start
         if i == -1 or i is S.Infinity:
             return self.stop - self.step
         rv = (self.stop if i < 0 else self.start) + i * self.step
         if rv.is_infinite:
             raise ValueError(ooslice)
         if rv < self.inf or rv > self.sup:
             raise IndexError("Range index out of range")
         return rv
Ejemplo n.º 46
0
def test_issue_18689():
    assert floor(floor(floor(x)) + 3) == floor(x) + 3
    assert ceiling(ceiling(ceiling(x)) + 1) == ceiling(x) + 1
    assert ceiling(ceiling(floor(x)) + 3) == floor(x) + 3
Ejemplo n.º 47
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def test_issue_11207():
    assert floor(floor(x)) == floor(x)
    assert floor(ceiling(x)) == ceiling(x)
    assert ceiling(floor(x)) == floor(x)
    assert ceiling(ceiling(x)) == ceiling(x)
Ejemplo n.º 48
0
def rsolve_hypergeometric(f, x, P, Q, k, m):
    """Solves RE of hypergeometric type.

    Attempts to solve RE of the form

    Q(k)*a(k + m) - P(k)*a(k)

    Transformations that preserve Hypergeometric type:

        a. x**n*f(x): b(k + m) = R(k - n)*b(k)
        b. f(A*x): b(k + m) = A**m*R(k)*b(k)
        c. f(x**n): b(k + n*m) = R(k/n)*b(k)
        d. f(x**(1/m)): b(k + 1) = R(k*m)*b(k)
        e. f'(x): b(k + m) = ((k + m + 1)/(k + 1))*R(k + 1)*b(k)

    Some of these transformations have been used to solve the RE.

    Returns
    =======

    formula : Expr
    ind : Expr
        Independent terms.
    order : int

    Examples
    ========

    >>> from sympy import exp, ln, S
    >>> from sympy.series.formal import rsolve_hypergeometric as rh
    >>> from sympy.abc import x, k

    >>> rh(exp(x), x, -S.One, (k + 1), k, 1)
    (Piecewise((1/factorial(k), Eq(Mod(k, 1), 0)), (0, True)), 1, 1)

    >>> rh(ln(1 + x), x, k**2, k*(k + 1), k, 1)
    (Piecewise(((-1)**(k - 1)*factorial(k - 1)/RisingFactorial(2, k - 1),
     Eq(Mod(k, 1), 0)), (0, True)), x, 2)

    References
    ==========

    .. [1] Formal Power Series - Dominik Gruntz, Wolfram Koepf
    .. [2] Power Series in Computer Algebra - Wolfram Koepf
    """
    result = _rsolve_hypergeometric(f, x, P, Q, k, m)

    if result is None:
        return None

    sol_list, ind, mp = result

    sol_dict = defaultdict(lambda: S.Zero)
    for res, cond in sol_list:
        j, mk = cond.as_coeff_Add()
        c = mk.coeff(k)

        if j.is_integer is False:
            res *= x**frac(j)
            j = floor(j)

        res = res.subs(k, (k - j) / c)
        cond = Eq(k % c, j % c)
        sol_dict[cond] += res  # Group together formula for same conditions

    sol = []
    for cond, res in sol_dict.items():
        sol.append((res, cond))
    sol.append((S.Zero, True))
    sol = Piecewise(*sol)

    if mp is -oo:
        s = S.Zero
    elif mp.is_integer is False:
        s = ceiling(mp)
    else:
        s = mp + 1

    #  save all the terms of
    #  form 1/x**k in ind
    if s < 0:
        ind += sum(sequence(sol * x**k, (k, s, -1)))
        s = S.Zero

    return (sol, ind, s)
Ejemplo n.º 49
0
def test_DiscreteMarkovChain():

    # pass only the name
    X = DiscreteMarkovChain("X")
    assert isinstance(X.state_space, Range)
    assert X.index_set == S.Naturals0
    assert isinstance(X.transition_probabilities, MatrixSymbol)
    t = symbols('t', positive=True, integer=True)
    assert isinstance(X[t], RandomIndexedSymbol)
    assert E(X[0]) == Expectation(X[0])
    raises(TypeError, lambda: DiscreteMarkovChain(1))
    raises(NotImplementedError, lambda: X(t))
    raises(NotImplementedError, lambda: X.communication_classes())
    raises(NotImplementedError, lambda: X.canonical_form())
    raises(NotImplementedError, lambda: X.decompose())

    nz = Symbol('n', integer=True)
    TZ = MatrixSymbol('M', nz, nz)
    SZ = Range(nz)
    YZ = DiscreteMarkovChain('Y', SZ, TZ)
    assert P(Eq(YZ[2], 1), Eq(YZ[1], 0)) == TZ[0, 1]

    raises(ValueError, lambda: sample_stochastic_process(t))
    raises(ValueError, lambda: next(sample_stochastic_process(X)))
    # pass name and state_space
    # any hashable object should be a valid state
    # states should be valid as a tuple/set/list/Tuple/Range
    sym, rainy, cloudy, sunny = symbols('a Rainy Cloudy Sunny', real=True)
    state_spaces = [(1, 2, 3), [Str('Hello'), sym, DiscreteMarkovChain],
                    Tuple(S(1), exp(sym), Str('World'), sympify=False),
                    Range(-1, 5, 2), [rainy, cloudy, sunny]]
    chains = [
        DiscreteMarkovChain("Y", state_space) for state_space in state_spaces
    ]

    for i, Y in enumerate(chains):
        assert isinstance(Y.transition_probabilities, MatrixSymbol)
        assert Y.state_space == state_spaces[i] or Y.state_space == FiniteSet(
            *state_spaces[i])
        assert Y.number_of_states == 3

        with ignore_warnings(
                UserWarning):  # TODO: Restore tests once warnings are removed
            assert P(Eq(Y[2], 1), Eq(Y[0], 2),
                     evaluate=False) == Probability(Eq(Y[2], 1), Eq(Y[0], 2))
        assert E(Y[0]) == Expectation(Y[0])

        raises(ValueError, lambda: next(sample_stochastic_process(Y)))

    raises(TypeError, lambda: DiscreteMarkovChain("Y", dict((1, 1))))
    Y = DiscreteMarkovChain("Y", Range(1, t, 2))
    assert Y.number_of_states == ceiling((t - 1) / 2)

    # pass name and transition_probabilities
    chains = [
        DiscreteMarkovChain("Y", trans_probs=Matrix([[]])),
        DiscreteMarkovChain("Y", trans_probs=Matrix([[0, 1], [1, 0]])),
        DiscreteMarkovChain("Y",
                            trans_probs=Matrix([[pi, 1 - pi], [sym, 1 - sym]]))
    ]
    for Z in chains:
        assert Z.number_of_states == Z.transition_probabilities.shape[0]
        assert isinstance(Z.transition_probabilities, ImmutableMatrix)

    # pass name, state_space and transition_probabilities
    T = Matrix([[0.5, 0.2, 0.3], [0.2, 0.5, 0.3], [0.2, 0.3, 0.5]])
    TS = MatrixSymbol('T', 3, 3)
    Y = DiscreteMarkovChain("Y", [0, 1, 2], T)
    YS = DiscreteMarkovChain("Y", ['One', 'Two', 3], TS)
    assert Y.joint_distribution(1, Y[2],
                                3) == JointDistribution(Y[1], Y[2], Y[3])
    raises(ValueError, lambda: Y.joint_distribution(Y[1].symbol, Y[2].symbol))
    assert P(Eq(Y[3], 2), Eq(Y[1], 1)).round(2) == Float(0.36, 2)
    assert (P(Eq(YS[3], 2), Eq(YS[1], 1)) -
            (TS[0, 2] * TS[1, 0] + TS[1, 1] * TS[1, 2] +
             TS[1, 2] * TS[2, 2])).simplify() == 0
    assert P(Eq(YS[1], 1), Eq(YS[2], 2)) == Probability(Eq(YS[1], 1))
    assert P(Eq(YS[3], 3), Eq(
        YS[1],
        1)) == TS[0, 2] * TS[1, 0] + TS[1, 1] * TS[1, 2] + TS[1, 2] * TS[2, 2]
    TO = Matrix([[0.25, 0.75, 0], [0, 0.25, 0.75], [0.75, 0, 0.25]])
    assert P(Eq(Y[3], 2),
             Eq(Y[1], 1) & TransitionMatrixOf(Y, TO)).round(3) == Float(
                 0.375, 3)
    with ignore_warnings(
            UserWarning):  ### TODO: Restore tests once warnings are removed
        assert E(Y[3], evaluate=False) == Expectation(Y[3])
        assert E(Y[3], Eq(Y[2], 1)).round(2) == Float(1.1, 3)
    TSO = MatrixSymbol('T', 4, 4)
    raises(
        ValueError,
        lambda: str(P(Eq(YS[3], 2),
                      Eq(YS[1], 1) & TransitionMatrixOf(YS, TSO))))
    raises(TypeError,
           lambda: DiscreteMarkovChain("Z", [0, 1, 2], symbols('M')))
    raises(
        ValueError,
        lambda: DiscreteMarkovChain("Z", [0, 1, 2], MatrixSymbol('T', 3, 4)))
    raises(ValueError, lambda: E(Y[3], Eq(Y[2], 6)))
    raises(ValueError, lambda: E(Y[2], Eq(Y[3], 1)))

    # extended tests for probability queries
    TO1 = Matrix([[Rational(1, 4), Rational(3, 4), 0],
                  [Rational(1, 3),
                   Rational(1, 3),
                   Rational(1, 3)], [0, Rational(1, 4),
                                     Rational(3, 4)]])
    assert P(
        And(Eq(Y[2], 1), Eq(Y[1], 1), Eq(Y[0], 0)),
        Eq(Probability(Eq(Y[0], 0)), Rational(1, 4))
        & TransitionMatrixOf(Y, TO1)) == Rational(1, 16)
    assert P(And(Eq(Y[2], 1), Eq(Y[1], 1), Eq(Y[0], 0)), TransitionMatrixOf(Y, TO1)) == \
            Probability(Eq(Y[0], 0))/4
    assert P(
        Lt(X[1], 2) & Gt(X[1], 0),
        Eq(X[0], 2) & StochasticStateSpaceOf(X, [0, 1, 2])
        & TransitionMatrixOf(X, TO1)) == Rational(1, 4)
    assert P(
        Lt(X[1], 2) & Gt(X[1], 0),
        Eq(X[0], 2) & StochasticStateSpaceOf(X, [None, 'None', 1])
        & TransitionMatrixOf(X, TO1)) == Rational(1, 4)
    assert P(
        Ne(X[1], 2) & Ne(X[1], 1),
        Eq(X[0], 2) & StochasticStateSpaceOf(X, [0, 1, 2])
        & TransitionMatrixOf(X, TO1)) is S.Zero
    assert P(
        Ne(X[1], 2) & Ne(X[1], 1),
        Eq(X[0], 2) & StochasticStateSpaceOf(X, [None, 'None', 1])
        & TransitionMatrixOf(X, TO1)) is S.Zero
    assert P(And(Eq(Y[2], 1), Eq(Y[1], 1), Eq(Y[0], 0)),
             Eq(Y[1], 1)) == 0.1 * Probability(Eq(Y[0], 0))

    # testing properties of Markov chain
    TO2 = Matrix([[S.One, 0, 0],
                  [Rational(1, 3),
                   Rational(1, 3),
                   Rational(1, 3)], [0, Rational(1, 4),
                                     Rational(3, 4)]])
    TO3 = Matrix([[Rational(1, 4), Rational(3, 4), 0],
                  [Rational(1, 3),
                   Rational(1, 3),
                   Rational(1, 3)], [0, Rational(1, 4),
                                     Rational(3, 4)]])
    Y2 = DiscreteMarkovChain('Y', trans_probs=TO2)
    Y3 = DiscreteMarkovChain('Y', trans_probs=TO3)
    assert Y3.fundamental_matrix() == ImmutableMatrix(
        [[176, 81, -132], [36, 141, -52], [-44, -39, 208]]) / 125
    assert Y2.is_absorbing_chain() == True
    assert Y3.is_absorbing_chain() == False
    assert Y2.canonical_form() == ([0, 1, 2], TO2)
    assert Y3.canonical_form() == ([0, 1, 2], TO3)
    assert Y2.decompose() == ([0, 1,
                               2], TO2[0:1, 0:1], TO2[1:3, 0:1], TO2[1:3, 1:3])
    assert Y3.decompose() == ([0, 1, 2], TO3, Matrix(0, 3,
                                                     []), Matrix(0, 0, []))
    TO4 = Matrix([[Rational(1, 5),
                   Rational(2, 5),
                   Rational(2, 5)], [Rational(1, 10), S.Half,
                                     Rational(2, 5)],
                  [Rational(3, 5),
                   Rational(3, 10),
                   Rational(1, 10)]])
    Y4 = DiscreteMarkovChain('Y', trans_probs=TO4)
    w = ImmutableMatrix([[Rational(11, 39),
                          Rational(16, 39),
                          Rational(4, 13)]])
    assert Y4.limiting_distribution == w
    assert Y4.is_regular() == True
    assert Y4.is_ergodic() == True
    TS1 = MatrixSymbol('T', 3, 3)
    Y5 = DiscreteMarkovChain('Y', trans_probs=TS1)
    assert Y5.limiting_distribution(w, TO4).doit() == True
    assert Y5.stationary_distribution(condition_set=True).subs(
        TS1, TO4).contains(w).doit() == S.true
    TO6 = Matrix([[S.One, 0, 0, 0, 0], [S.Half, 0, S.Half, 0, 0],
                  [0, S.Half, 0, S.Half, 0], [0, 0, S.Half, 0, S.Half],
                  [0, 0, 0, 0, 1]])
    Y6 = DiscreteMarkovChain('Y', trans_probs=TO6)
    assert Y6.fundamental_matrix() == ImmutableMatrix(
        [[Rational(3, 2), S.One, S.Half], [S.One, S(2), S.One],
         [S.Half, S.One, Rational(3, 2)]])
    assert Y6.absorbing_probabilities() == ImmutableMatrix(
        [[Rational(3, 4), Rational(1, 4)], [S.Half, S.Half],
         [Rational(1, 4), Rational(3, 4)]])
    TO7 = Matrix([[Rational(1, 2),
                   Rational(1, 4),
                   Rational(1, 4)], [Rational(1, 2), 0,
                                     Rational(1, 2)],
                  [Rational(1, 4),
                   Rational(1, 4),
                   Rational(1, 2)]])
    Y7 = DiscreteMarkovChain('Y', trans_probs=TO7)
    assert Y7.is_absorbing_chain() == False
    assert Y7.fundamental_matrix() == ImmutableMatrix(
        [[Rational(86, 75),
          Rational(1, 25),
          Rational(-14, 75)],
         [Rational(2, 25), Rational(21, 25),
          Rational(2, 25)],
         [Rational(-14, 75),
          Rational(1, 25),
          Rational(86, 75)]])

    # test for zero-sized matrix functionality
    X = DiscreteMarkovChain('X', trans_probs=Matrix([[]]))
    assert X.number_of_states == 0
    assert X.stationary_distribution() == Matrix([[]])
    assert X.communication_classes() == []
    assert X.canonical_form() == ([], Matrix([[]]))
    assert X.decompose() == ([], Matrix([[]]), Matrix([[]]), Matrix([[]]))
    assert X.is_regular() == False
    assert X.is_ergodic() == False

    # test communication_class
    # see https://drive.google.com/drive/folders/1HbxLlwwn2b3U8Lj7eb_ASIUb5vYaNIjg?usp=sharing
    # tutorial 2.pdf
    TO7 = Matrix([[0, 5, 5, 0, 0], [0, 0, 0, 10, 0], [5, 0, 5, 0, 0],
                  [0, 10, 0, 0, 0], [0, 3, 0, 3, 4]]) / 10
    Y7 = DiscreteMarkovChain('Y', trans_probs=TO7)
    tuples = Y7.communication_classes()
    classes, recurrence, periods = list(zip(*tuples))
    assert classes == ([1, 3], [0, 2], [4])
    assert recurrence == (True, False, False)
    assert periods == (2, 1, 1)

    TO8 = Matrix([[0, 0, 0, 10, 0, 0], [5, 0, 5, 0, 0, 0], [0, 4, 0, 0, 0, 6],
                  [10, 0, 0, 0, 0, 0], [0, 10, 0, 0, 0, 0], [0, 0, 0, 5, 5, 0]
                  ]) / 10
    Y8 = DiscreteMarkovChain('Y', trans_probs=TO8)
    tuples = Y8.communication_classes()
    classes, recurrence, periods = list(zip(*tuples))
    assert classes == ([0, 3], [1, 2, 5, 4])
    assert recurrence == (True, False)
    assert periods == (2, 2)

    TO9 = Matrix(
        [[2, 0, 0, 3, 0, 0, 3, 2, 0, 0], [0, 10, 0, 0, 0, 0, 0, 0, 0, 0],
         [0, 2, 2, 0, 0, 0, 0, 0, 3, 3], [0, 0, 0, 3, 0, 0, 6, 1, 0, 0],
         [0, 0, 0, 0, 5, 5, 0, 0, 0, 0], [0, 0, 0, 0, 0, 10, 0, 0, 0, 0],
         [4, 0, 0, 5, 0, 0, 1, 0, 0, 0], [2, 0, 0, 4, 0, 0, 2, 2, 0, 0],
         [3, 0, 1, 0, 0, 0, 0, 0, 4, 2], [0, 0, 4, 0, 0, 0, 0, 0, 3, 3]]) / 10
    Y9 = DiscreteMarkovChain('Y', trans_probs=TO9)
    tuples = Y9.communication_classes()
    classes, recurrence, periods = list(zip(*tuples))
    assert classes == ([0, 3, 6, 7], [1], [2, 8, 9], [5], [4])
    assert recurrence == (True, True, False, True, False)
    assert periods == (1, 1, 1, 1, 1)

    # test canonical form
    # see https://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/Chapter11.pdf
    # example 11.13
    T = Matrix([[1, 0, 0, 0, 0], [S(1) / 2, 0, S(1) / 2, 0, 0],
                [0, S(1) / 2, 0, S(1) / 2, 0], [0, 0,
                                                S(1) / 2, 0,
                                                S(1) / 2], [0, 0, 0, 0,
                                                            S(1)]])
    DW = DiscreteMarkovChain('DW', [0, 1, 2, 3, 4], T)
    states, A, B, C = DW.decompose()
    assert states == [0, 4, 1, 2, 3]
    assert A == Matrix([[1, 0], [0, 1]])
    assert B == Matrix([[S(1) / 2, 0], [0, 0], [0, S(1) / 2]])
    assert C == Matrix([[0, S(1) / 2, 0], [S(1) / 2, 0, S(1) / 2],
                        [0, S(1) / 2, 0]])
    states, new_matrix = DW.canonical_form()
    assert states == [0, 4, 1, 2, 3]
    assert new_matrix == Matrix([[1, 0, 0, 0, 0], [0, 1, 0, 0, 0],
                                 [S(1) / 2, 0, 0, S(1) / 2, 0],
                                 [0, 0, S(1) / 2, 0,
                                  S(1) / 2], [0, S(1) / 2, 0,
                                              S(1) / 2, 0]])

    # test regular and ergodic
    # https://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/Chapter11.pdf
    T = Matrix([[0, 4, 0, 0, 0], [1, 0, 3, 0, 0], [0, 2, 0, 2, 0],
                [0, 0, 3, 0, 1], [0, 0, 0, 4, 0]]) / 4
    X = DiscreteMarkovChain('X', trans_probs=T)
    assert not X.is_regular()
    assert X.is_ergodic()
    T = Matrix([[0, 1], [1, 0]])
    X = DiscreteMarkovChain('X', trans_probs=T)
    assert not X.is_regular()
    assert X.is_ergodic()
    # http://www.math.wisc.edu/~valko/courses/331/MC2.pdf
    T = Matrix([[2, 1, 1], [2, 0, 2], [1, 1, 2]]) / 4
    X = DiscreteMarkovChain('X', trans_probs=T)
    assert X.is_regular()
    assert X.is_ergodic()
    # https://docs.ufpr.br/~lucambio/CE222/1S2014/Kemeny-Snell1976.pdf
    T = Matrix([[1, 1], [1, 1]]) / 2
    X = DiscreteMarkovChain('X', trans_probs=T)
    assert X.is_regular()
    assert X.is_ergodic()

    # test is_absorbing_chain
    T = Matrix([[0, 1, 0], [1, 0, 0], [0, 0, 1]])
    X = DiscreteMarkovChain('X', trans_probs=T)
    assert not X.is_absorbing_chain()
    # https://en.wikipedia.org/wiki/Absorbing_Markov_chain
    T = Matrix([[1, 1, 0, 0], [0, 1, 1, 0], [1, 0, 0, 1], [0, 0, 0, 2]]) / 2
    X = DiscreteMarkovChain('X', trans_probs=T)
    assert X.is_absorbing_chain()
    T = Matrix([[2, 0, 0, 0, 0], [1, 0, 1, 0, 0], [0, 1, 0, 1, 0],
                [0, 0, 1, 0, 1], [0, 0, 0, 0, 2]]) / 2
    X = DiscreteMarkovChain('X', trans_probs=T)
    assert X.is_absorbing_chain()

    # test custom state space
    Y10 = DiscreteMarkovChain('Y', [1, 2, 3], TO2)
    tuples = Y10.communication_classes()
    classes, recurrence, periods = list(zip(*tuples))
    assert classes == ([1], [2, 3])
    assert recurrence == (True, False)
    assert periods == (1, 1)
    assert Y10.canonical_form() == ([1, 2, 3], TO2)
    assert Y10.decompose() == ([1, 2, 3], TO2[0:1, 0:1], TO2[1:3,
                                                             0:1], TO2[1:3,
                                                                       1:3])

    # testing miscellaneous queries
    T = Matrix([[S.Half, Rational(1, 4),
                 Rational(1, 4)], [Rational(1, 3), 0,
                                   Rational(2, 3)], [S.Half, S.Half, 0]])
    X = DiscreteMarkovChain('X', [0, 1, 2], T)
    assert P(
        Eq(X[1], 2) & Eq(X[2], 1) & Eq(X[3], 0),
        Eq(P(Eq(X[1], 0)), Rational(1, 4))
        & Eq(P(Eq(X[1], 1)), Rational(1, 4))) == Rational(1, 12)
    assert P(Eq(X[2], 1) | Eq(X[2], 2), Eq(X[1], 1)) == Rational(2, 3)
    assert P(Eq(X[2], 1) & Eq(X[2], 2), Eq(X[1], 1)) is S.Zero
    assert P(Ne(X[2], 2), Eq(X[1], 1)) == Rational(1, 3)
    assert E(X[1]**2, Eq(X[0], 1)) == Rational(8, 3)
    assert variance(X[1], Eq(X[0], 1)) == Rational(8, 9)
    raises(ValueError, lambda: E(X[1], Eq(X[2], 1)))
    raises(ValueError, lambda: DiscreteMarkovChain('X', [0, 1], T))

    # testing miscellaneous queries with different state space
    X = DiscreteMarkovChain('X', ['A', 'B', 'C'], T)
    assert P(
        Eq(X[1], 2) & Eq(X[2], 1) & Eq(X[3], 0),
        Eq(P(Eq(X[1], 0)), Rational(1, 4))
        & Eq(P(Eq(X[1], 1)), Rational(1, 4))) == Rational(1, 12)
    assert P(Eq(X[2], 1) | Eq(X[2], 2), Eq(X[1], 1)) == Rational(2, 3)
    assert P(Eq(X[2], 1) & Eq(X[2], 2), Eq(X[1], 1)) is S.Zero
    assert P(Ne(X[2], 2), Eq(X[1], 1)) == Rational(1, 3)
    a = X.state_space.args[0]
    c = X.state_space.args[2]
    assert (E(X[1]**2, Eq(X[0], 1)) -
            (a**2 / 3 + 2 * c**2 / 3)).simplify() == 0
    assert (variance(X[1], Eq(X[0], 1)) -
            (2 * (-a / 3 + c / 3)**2 / 3 +
             (2 * a / 3 - 2 * c / 3)**2 / 3)).simplify() == 0
    raises(ValueError, lambda: E(X[1], Eq(X[2], 1)))

    #testing queries with multiple RandomIndexedSymbols
    T = Matrix([[Rational(5, 10),
                 Rational(3, 10),
                 Rational(2, 10)],
                [Rational(2, 10),
                 Rational(7, 10),
                 Rational(1, 10)],
                [Rational(3, 10),
                 Rational(3, 10),
                 Rational(4, 10)]])
    Y = DiscreteMarkovChain("Y", [0, 1, 2], T)
    assert P(Eq(Y[7], Y[5]), Eq(Y[2], 0)).round(5) == Float(0.44428, 5)
    assert P(Gt(Y[3], Y[1]), Eq(Y[0], 0)).round(2) == Float(0.36, 2)
    assert P(Le(Y[5], Y[10]), Eq(Y[4], 2)).round(6) == Float(0.583120, 6)
    assert Float(P(Eq(Y[10], Y[5]), Eq(Y[4], 1)),
                 14) == Float(1 - P(Ne(Y[10], Y[5]), Eq(Y[4], 1)), 14)
    assert Float(P(Gt(Y[8], Y[9]), Eq(Y[3], 2)),
                 14) == Float(1 - P(Le(Y[8], Y[9]), Eq(Y[3], 2)), 14)
    assert Float(P(Lt(Y[1], Y[4]), Eq(Y[0], 0)),
                 14) == Float(1 - P(Ge(Y[1], Y[4]), Eq(Y[0], 0)), 14)
    assert P(Eq(Y[5], Y[10]), Eq(Y[2], 1)) == P(Eq(Y[10], Y[5]), Eq(Y[2], 1))
    assert P(Gt(Y[1], Y[2]), Eq(Y[0], 1)) == P(Lt(Y[2], Y[1]), Eq(Y[0], 1))
    assert P(Ge(Y[7], Y[6]), Eq(Y[4], 1)) == P(Le(Y[6], Y[7]), Eq(Y[4], 1))

    #test symbolic queries
    a, b, c, d = symbols('a b c d')
    T = Matrix([[Rational(1, 10),
                 Rational(4, 10),
                 Rational(5, 10)],
                [Rational(3, 10),
                 Rational(4, 10),
                 Rational(3, 10)],
                [Rational(7, 10),
                 Rational(2, 10),
                 Rational(1, 10)]])
    Y = DiscreteMarkovChain("Y", [0, 1, 2], T)
    query = P(Eq(Y[a], b), Eq(Y[c], d))
    assert query.subs({
        a: 10,
        b: 2,
        c: 5,
        d: 1
    }).evalf().round(4) == P(Eq(Y[10], 2), Eq(Y[5], 1)).round(4)
    assert query.subs({
        a: 15,
        b: 0,
        c: 10,
        d: 1
    }).evalf().round(4) == P(Eq(Y[15], 0), Eq(Y[10], 1)).round(4)
    query_gt = P(Gt(Y[a], b), Eq(Y[c], d))
    query_le = P(Le(Y[a], b), Eq(Y[c], d))
    assert query_gt.subs({
        a: 5,
        b: 2,
        c: 1,
        d: 0
    }).evalf() + query_le.subs({
        a: 5,
        b: 2,
        c: 1,
        d: 0
    }).evalf() == 1
    query_ge = P(Ge(Y[a], b), Eq(Y[c], d))
    query_lt = P(Lt(Y[a], b), Eq(Y[c], d))
    assert query_ge.subs({
        a: 4,
        b: 1,
        c: 0,
        d: 2
    }).evalf() + query_lt.subs({
        a: 4,
        b: 1,
        c: 0,
        d: 2
    }).evalf() == 1

    #test issue 20078
    assert (2 * Y[1] + 3 * Y[1]).simplify() == 5 * Y[1]
    assert (2 * Y[1] - 3 * Y[1]).simplify() == -Y[1]
    assert (2 * (0.25 * Y[1])).simplify() == 0.5 * Y[1]
    assert ((2 * Y[1]) * (0.25 * Y[1])).simplify() == 0.5 * Y[1]**2
    assert (Y[1]**2 + Y[1]**3).simplify() == (Y[1] + 1) * Y[1]**2
Ejemplo n.º 50
0
    def _intersect(self, other):
        from sympy.functions.elementary.integers import ceiling, floor
        from sympy.functions.elementary.complexes import sign

        if other is S.Naturals:
            return self._intersect(Interval(1, S.Infinity))

        if other is S.Integers:
            return self

        if other.is_Interval:
            if not all(i.is_number for i in other.args[:2]):
                return

            # In case of null Range, return an EmptySet.
            if self.size == 0:
                return S.EmptySet

            # trim down to self's size, and represent
            # as a Range with step 1.
            start = ceiling(max(other.inf, self.inf))
            if start not in other:
                start += 1
            end = floor(min(other.sup, self.sup))
            if end not in other:
                end -= 1
            return self.intersect(Range(start, end + 1))

        if isinstance(other, Range):
            from sympy.solvers.diophantine import diop_linear
            from sympy.core.numbers import ilcm

            # non-overlap quick exits
            if not other:
                return S.EmptySet
            if not self:
                return S.EmptySet
            if other.sup < self.inf:
                return S.EmptySet
            if other.inf > self.sup:
                return S.EmptySet

            # work with finite end at the start
            r1 = self
            if r1.start.is_infinite:
                r1 = r1.reversed
            r2 = other
            if r2.start.is_infinite:
                r2 = r2.reversed

            # this equation represents the values of the Range;
            # it's a linear equation
            eq = lambda r, i: r.start + i*r.step

            # we want to know when the two equations might
            # have integer solutions so we use the diophantine
            # solver
            a, b = diop_linear(eq(r1, Dummy()) - eq(r2, Dummy()))

            # check for no solution
            no_solution = a is None and b is None
            if no_solution:
                return S.EmptySet

            # there is a solution
            # -------------------

            # find the coincident point, c
            a0 = a.as_coeff_Add()[0]
            c = eq(r1, a0)

            # find the first point, if possible, in each range
            # since c may not be that point
            def _first_finite_point(r1, c):
                if c == r1.start:
                    return c
                # st is the signed step we need to take to
                # get from c to r1.start
                st = sign(r1.start - c)*step
                # use Range to calculate the first point:
                # we want to get as close as possible to
                # r1.start; the Range will not be null since
                # it will at least contain c
                s1 = Range(c, r1.start + st, st)[-1]
                if s1 == r1.start:
                    pass
                else:
                    # if we didn't hit r1.start then, if the
                    # sign of st didn't match the sign of r1.step
                    # we are off by one and s1 is not in r1
                    if sign(r1.step) != sign(st):
                        s1 -= st
                if s1 not in r1:
                    return
                return s1

            # calculate the step size of the new Range
            step = abs(ilcm(r1.step, r2.step))
            s1 = _first_finite_point(r1, c)
            if s1 is None:
                return S.EmptySet
            s2 = _first_finite_point(r2, c)
            if s2 is None:
                return S.EmptySet

            # replace the corresponding start or stop in
            # the original Ranges with these points; the
            # result must have at least one point since
            # we know that s1 and s2 are in the Ranges
            def _updated_range(r, first):
                st = sign(r.step)*step
                if r.start.is_finite:
                    rv = Range(first, r.stop, st)
                else:
                    rv = Range(r.start, first + st, st)
                return rv
            r1 = _updated_range(self, s1)
            r2 = _updated_range(other, s2)

            # work with them both in the increasing direction
            if sign(r1.step) < 0:
                r1 = r1.reversed
            if sign(r2.step) < 0:
                r2 = r2.reversed

            # return clipped Range with positive step; it
            # can't be empty at this point
            start = max(r1.start, r2.start)
            stop = min(r1.stop, r2.stop)
            return Range(start, stop, step)
        else:
            return
Ejemplo n.º 51
0
def intersection_sets(a, b):
    from sympy.functions.elementary.integers import floor, ceiling
    if b._inf == S.NegativeInfinity and b._sup == S.Infinity:
        return a
    s = Range(ceiling(b.left), floor(b.right) + 1)
    return intersection_sets(s, b)  # take out endpoints if open interval
Ejemplo n.º 52
0
 def __getitem__(self, i):
     from sympy.functions.elementary.integers import ceiling
     ooslice = "cannot slice from the end with an infinite value"
     zerostep = "slice step cannot be zero"
     # if we had to take every other element in the following
     # oo, ..., 6, 4, 2, 0
     # we might get oo, ..., 4, 0 or oo, ..., 6, 2
     ambiguous = "cannot unambiguously re-stride from the end " + \
         "with an infinite value"
     if isinstance(i, slice):
         if self.size.is_finite:
             start, stop, step = i.indices(self.size)
             n = ceiling((stop - start)/step)
             if n <= 0:
                 return Range(0)
             canonical_stop = start + n*step
             end = canonical_stop - step
             ss = step*self.step
             return Range(self[start], self[end] + ss, ss)
         else:  # infinite Range
             start = i.start
             stop = i.stop
             if i.step == 0:
                 raise ValueError(zerostep)
             step = i.step or 1
             ss = step*self.step
             #---------------------
             # handle infinite on right
             #   e.g. Range(0, oo) or Range(0, -oo, -1)
             # --------------------
             if self.stop.is_infinite:
                 # start and stop are not interdependent --
                 # they only depend on step --so we use the
                 # equivalent reversed values
                 return self.reversed[
                     stop if stop is None else -stop + 1:
                     start if start is None else -start:
                     step].reversed
             #---------------------
             # handle infinite on the left
             #   e.g. Range(oo, 0, -1) or Range(-oo, 0)
             # --------------------
             # consider combinations of
             # start/stop {== None, < 0, == 0, > 0} and
             # step {< 0, > 0}
             if start is None:
                 if stop is None:
                     if step < 0:
                         return Range(self[-1], self.start, ss)
                     elif step > 1:
                         raise ValueError(ambiguous)
                     else:  # == 1
                         return self
                 elif stop < 0:
                     if step < 0:
                         return Range(self[-1], self[stop], ss)
                     else:  # > 0
                         return Range(self.start, self[stop], ss)
                 elif stop == 0:
                     if step > 0:
                         return Range(0)
                     else:  # < 0
                         raise ValueError(ooslice)
                 elif stop == 1:
                     if step > 0:
                         raise ValueError(ooslice)  # infinite singleton
                     else:  # < 0
                         raise ValueError(ooslice)
                 else:  # > 1
                     raise ValueError(ooslice)
             elif start < 0:
                 if stop is None:
                     if step < 0:
                         return Range(self[start], self.start, ss)
                     else:  # > 0
                         return Range(self[start], self.stop, ss)
                 elif stop < 0:
                     return Range(self[start], self[stop], ss)
                 elif stop == 0:
                     if step < 0:
                         raise ValueError(ooslice)
                     else:  # > 0
                         return Range(0)
                 elif stop > 0:
                     raise ValueError(ooslice)
             elif start == 0:
                 if stop is None:
                     if step < 0:
                         raise ValueError(ooslice)  # infinite singleton
                     elif step > 1:
                         raise ValueError(ambiguous)
                     else:  # == 1
                         return self
                 elif stop < 0:
                     if step > 1:
                         raise ValueError(ambiguous)
                     elif step == 1:
                         return Range(self.start, self[stop], ss)
                     else:  # < 0
                         return Range(0)
                 else:  # >= 0
                     raise ValueError(ooslice)
             elif start > 0:
                 raise ValueError(ooslice)
     else:
         if not self:
             raise IndexError('Range index out of range')
         if i == 0:
             return self.start
         if i == -1 or i is S.Infinity:
             return self.stop - self.step
         rv = (self.stop if i < 0 else self.start) + i*self.step
         if rv.is_infinite:
             raise ValueError(ooslice)
         if rv < self.inf or rv > self.sup:
             raise IndexError("Range index out of range")
         return rv
Ejemplo n.º 53
0
def primerange(a, b):
    """ Generate a list of all prime numbers in the range [a, b).

        If the range exists in the default sieve, the values will
        be returned from there; otherwise values will be returned
        but will not modify the sieve.

        Notes
        =====

        Some famous conjectures about the occurence of primes in a given
        range are [1]:

        - Twin primes: though often not, the following will give 2 primes
                    an infinite number of times:
                        primerange(6*n - 1, 6*n + 2)
        - Legendre's: the following always yields at least one prime
                        primerange(n**2, (n+1)**2+1)
        - Bertrand's (proven): there is always a prime in the range
                        primerange(n, 2*n)
        - Brocard's: there are at least four primes in the range
                        primerange(prime(n)**2, prime(n+1)**2)

        The average gap between primes is log(n) [2]; the gap between
        primes can be arbitrarily large since sequences of composite
        numbers are arbitrarily large, e.g. the numbers in the sequence
        n! + 2, n! + 3 ... n! + n are all composite.

        References
        ==========

        1. http://en.wikipedia.org/wiki/Prime_number
        2. http://primes.utm.edu/notes/gaps.html

        Examples
        ========

        >>> from sympy import primerange, sieve
        >>> print([i for i in primerange(1, 30)])
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

        The Sieve method, primerange, is generally faster but it will
        occupy more memory as the sieve stores values. The default
        instance of Sieve, named sieve, can be used:

        >>> list(sieve.primerange(1, 30))
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

        See Also
        ========

        nextprime : Return the ith prime greater than n
        prevprime : Return the largest prime smaller than n
        randprime : Returns a random prime in a given range
        primorial : Returns the product of primes based on condition
        Sieve.primerange : return range from already computed primes
                           or extend the sieve to contain the requested
                           range.
    """
    from sympy.functions.elementary.integers import ceiling

    # if we already have the range, return it
    if b <= sieve._list[-1]:
        for i in sieve.primerange(a, b):
            yield i
        return
    # otherwise compute, without storing, the desired range
    if a >= b:
        return
    # wrapping ceiling in int will raise an error if there was a problem
    # determining whether the expression was exactly an integer or not
    a = int(ceiling(a)) - 1
    b = int(ceiling(b))
    while 1:
        a = nextprime(a)
        if a < b:
            yield a
        else:
            return
Ejemplo n.º 54
0
 def _intersect(self, other):
     if other.is_Interval and other.measure < oo:
         s = Range(ceiling(other.left), floor(other.right) + 1)
         return s.intersect(other)  # take out endpoints if open interval
     return None
Ejemplo n.º 55
0
def primerange(a, b):
    """ Generate a list of all prime numbers in the range [a, b).

        If the range exists in the default sieve, the values will
        be returned from there; otherwise values will be returned
        but will not modify the sieve.

        Notes
        =====

        Some famous conjectures about the occurrence of primes in a given
        range are [1]:

        - Twin primes: though often not, the following will give 2 primes
                    an infinite number of times:
                        primerange(6*n - 1, 6*n + 2)
        - Legendre's: the following always yields at least one prime
                        primerange(n**2, (n+1)**2+1)
        - Bertrand's (proven): there is always a prime in the range
                        primerange(n, 2*n)
        - Brocard's: there are at least four primes in the range
                        primerange(prime(n)**2, prime(n+1)**2)

        The average gap between primes is log(n) [2]; the gap between
        primes can be arbitrarily large since sequences of composite
        numbers are arbitrarily large, e.g. the numbers in the sequence
        n! + 2, n! + 3 ... n! + n are all composite.

        References
        ==========

        1. https://en.wikipedia.org/wiki/Prime_number
        2. http://primes.utm.edu/notes/gaps.html

        Examples
        ========

        >>> from sympy import primerange, sieve
        >>> print([i for i in primerange(1, 30)])
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

        The Sieve method, primerange, is generally faster but it will
        occupy more memory as the sieve stores values. The default
        instance of Sieve, named sieve, can be used:

        >>> list(sieve.primerange(1, 30))
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

        See Also
        ========

        nextprime : Return the ith prime greater than n
        prevprime : Return the largest prime smaller than n
        randprime : Returns a random prime in a given range
        primorial : Returns the product of primes based on condition
        Sieve.primerange : return range from already computed primes
                           or extend the sieve to contain the requested
                           range.
    """
    from sympy.functions.elementary.integers import ceiling

    if a >= b:
        return
    # if we already have the range, return it
    if b <= sieve._list[-1]:
        for i in sieve.primerange(a, b):
            yield i
        return
    # otherwise compute, without storing, the desired range.

    # wrapping ceiling in as_int will raise an error if there was a problem
    # determining whether the expression was exactly an integer or not
    a = as_int(ceiling(a)) - 1
    b = as_int(ceiling(b))
    while 1:
        a = nextprime(a)
        if a < b:
            yield a
        else:
            return
Ejemplo n.º 56
0
def test_issue_13098():
    assert floor(log(S('9.' + '9' * 20), 10)) == 0
    assert ceiling(log(S('9.' + '9' * 20), 10)) == 1
    assert floor(log(20 - S('9.' + '9' * 20), 10)) == 1
    assert ceiling(log(20 - S('9.' + '9' * 20), 10)) == 2
Ejemplo n.º 57
0
 def _intersect(self, other):
     from sympy.functions.elementary.integers import floor, ceiling
     if other.is_Interval and other.measure < S.Infinity:
         s = Range(ceiling(other.left), floor(other.right) + 1)
         return s.intersect(other)  # take out endpoints if open interval
     return None
Ejemplo n.º 58
0
def test_ceiling():

    assert ceiling(nan) is nan

    assert ceiling(oo) is oo
    assert ceiling(-oo) is -oo
    assert ceiling(zoo) is zoo

    assert ceiling(0) == 0

    assert ceiling(1) == 1
    assert ceiling(-1) == -1

    assert ceiling(E) == 3
    assert ceiling(-E) == -2

    assert ceiling(2*E) == 6
    assert ceiling(-2*E) == -5

    assert ceiling(pi) == 4
    assert ceiling(-pi) == -3

    assert ceiling(S.Half) == 1
    assert ceiling(Rational(-1, 2)) == 0

    assert ceiling(Rational(7, 3)) == 3
    assert ceiling(-Rational(7, 3)) == -2

    assert ceiling(Float(17.0)) == 17
    assert ceiling(-Float(17.0)) == -17

    assert ceiling(Float(7.69)) == 8
    assert ceiling(-Float(7.69)) == -7

    assert ceiling(I) == I
    assert ceiling(-I) == -I
    e = ceiling(i)
    assert e.func is ceiling and e.args[0] == i

    assert ceiling(oo*I) == oo*I
    assert ceiling(-oo*I) == -oo*I
    assert ceiling(exp(I*pi/4)*oo) == exp(I*pi/4)*oo

    assert ceiling(2*I) == 2*I
    assert ceiling(-2*I) == -2*I

    assert ceiling(I/2) == I
    assert ceiling(-I/2) == 0

    assert ceiling(E + 17) == 20
    assert ceiling(pi + 2) == 6

    assert ceiling(E + pi) == 6
    assert ceiling(I + pi) == I + 4

    assert ceiling(ceiling(pi)) == 4
    assert ceiling(ceiling(y)) == ceiling(y)
    assert ceiling(ceiling(x)) == ceiling(x)

    assert unchanged(ceiling, x)
    assert unchanged(ceiling, 2*x)
    assert unchanged(ceiling, k*x)

    assert ceiling(k) == k
    assert ceiling(2*k) == 2*k
    assert ceiling(k*n) == k*n

    assert unchanged(ceiling, k/2)

    assert unchanged(ceiling, x + y)

    assert ceiling(x + 3) == ceiling(x) + 3
    assert ceiling(x + k) == ceiling(x) + k

    assert ceiling(y + 3) == ceiling(y) + 3
    assert ceiling(y + k) == ceiling(y) + k

    assert ceiling(3 + pi + y*I) == 7 + ceiling(y)*I

    assert ceiling(k + n) == k + n

    assert unchanged(ceiling, x*I)
    assert ceiling(k*I) == k*I

    assert ceiling(Rational(23, 10) - E*I) == 3 - 2*I

    assert ceiling(sin(1)) == 1
    assert ceiling(sin(-1)) == 0

    assert ceiling(exp(2)) == 8

    assert ceiling(-log(8)/log(2)) != -2
    assert int(ceiling(-log(8)/log(2)).evalf(chop=True)) == -3

    assert ceiling(factorial(50)/exp(1)) == \
        11188719610782480504630258070757734324011354208865721592720336801

    assert (ceiling(y) >= y) == True
    assert (ceiling(y) > y) == False
    assert (ceiling(y) < y) == False
    assert (ceiling(y) <= y) == False
    assert (ceiling(x) >= x).is_Relational  # x could be non-real
    assert (ceiling(x) < x).is_Relational
    assert (ceiling(x) >= y).is_Relational  # arg is not same as rhs
    assert (ceiling(x) < y).is_Relational
    assert (ceiling(y) >= -oo) == True
    assert (ceiling(y) > -oo) == True
    assert (ceiling(y) <= oo) == True
    assert (ceiling(y) < oo) == True

    assert ceiling(y).rewrite(floor) == -floor(-y)
    assert ceiling(y).rewrite(frac) == y + frac(-y)
    assert ceiling(y).rewrite(floor).subs(y, -pi) == -floor(pi)
    assert ceiling(y).rewrite(floor).subs(y, E) == -floor(-E)
    assert ceiling(y).rewrite(frac).subs(y, pi) == ceiling(pi)
    assert ceiling(y).rewrite(frac).subs(y, -E) == ceiling(-E)

    assert Eq(ceiling(y), y + frac(-y))
    assert Eq(ceiling(y), -floor(-y))

    neg = Symbol('neg', negative=True)
    nn = Symbol('nn', nonnegative=True)
    pos = Symbol('pos', positive=True)
    np = Symbol('np', nonpositive=True)

    assert (ceiling(neg) <= 0) == True
    assert (ceiling(neg) < 0) == (neg <= -1)
    assert (ceiling(neg) > 0) == False
    assert (ceiling(neg) >= 0) == (neg > -1)
    assert (ceiling(neg) > -3) == (neg > -3)
    assert (ceiling(neg) <= 10) == (neg <= 10)

    assert (ceiling(nn) < 0) == False
    assert (ceiling(nn) >= 0) == True

    assert (ceiling(pos) < 0) == False
    assert (ceiling(pos) <= 0) == False
    assert (ceiling(pos) > 0) == True
    assert (ceiling(pos) >= 0) == True
    assert (ceiling(pos) >= 1) == True
    assert (ceiling(pos) > 5) == (pos > 5)

    assert (ceiling(np) <= 0) == True
    assert (ceiling(np) > 0) == False

    assert ceiling(neg).is_positive == False
    assert ceiling(neg).is_nonpositive == True
    assert ceiling(nn).is_positive is None
    assert ceiling(nn).is_nonpositive is None
    assert ceiling(pos).is_positive == True
    assert ceiling(pos).is_nonpositive == False
    assert ceiling(np).is_positive == False
    assert ceiling(np).is_nonpositive == True

    assert (ceiling(7, evaluate=False) >= 7) == True
    assert (ceiling(7, evaluate=False) > 7) == False
    assert (ceiling(7, evaluate=False) <= 7) == True
    assert (ceiling(7, evaluate=False) < 7) == False

    assert (ceiling(7, evaluate=False) >= 6) == True
    assert (ceiling(7, evaluate=False) > 6) == True
    assert (ceiling(7, evaluate=False) <= 6) == False
    assert (ceiling(7, evaluate=False) < 6) == False

    assert (ceiling(7, evaluate=False) >= 8) == False
    assert (ceiling(7, evaluate=False) > 8) == False
    assert (ceiling(7, evaluate=False) <= 8) == True
    assert (ceiling(7, evaluate=False) < 8) == True

    assert (ceiling(x) <= 5.5) == Le(ceiling(x), 5.5, evaluate=False)
    assert (ceiling(x) >= -3.2) == Ge(ceiling(x), -3.2, evaluate=False)
    assert (ceiling(x) < 2.9) == Lt(ceiling(x), 2.9, evaluate=False)
    assert (ceiling(x) > -1.7) == Gt(ceiling(x), -1.7, evaluate=False)

    assert (ceiling(y) <= 5.5) == (y <= 5)
    assert (ceiling(y) >= -3.2) == (y > -4)
    assert (ceiling(y) < 2.9) == (y <= 2)
    assert (ceiling(y) > -1.7) == (y > -2)

    assert (ceiling(y) <= n) == (y <= n)
    assert (ceiling(y) >= n) == (y > n - 1)
    assert (ceiling(y) < n) == (y <= n - 1)
    assert (ceiling(y) > n) == (y > n)