Exemple #1
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def test_pow1():
    assert refine((-1)**x, Q.even(x)) == 1
    assert refine((-1)**x, Q.odd(x)) == -1
    assert refine((-2)**x, Q.even(x)) == 2**x

    # nested powers
    assert refine(sqrt(x**2)) != Abs(x)
    assert refine(sqrt(x**2), Q.complex(x)) != Abs(x)
    assert refine(sqrt(x**2), Q.real(x)) == Abs(x)
    assert refine(sqrt(x**2), Q.positive(x)) == x
    assert refine((x**3)**Rational(1, 3)) != x

    assert refine((x**3)**Rational(1, 3), Q.real(x)) != x
    assert refine((x**3)**Rational(1, 3), Q.positive(x)) == x

    assert refine(sqrt(1/x), Q.real(x)) != 1/sqrt(x)
    assert refine(sqrt(1/x), Q.positive(x)) == 1/sqrt(x)

    # powers of (-1)
    assert refine((-1)**(x + y), Q.even(x)) == (-1)**y
    assert refine((-1)**(x + y + z), Q.odd(x) & Q.odd(z)) == (-1)**y
    assert refine((-1)**(x + y + 1), Q.odd(x)) == (-1)**y
    assert refine((-1)**(x + y + 2), Q.odd(x)) == (-1)**(y + 1)
    assert refine((-1)**(x + 3)) == (-1)**(x + 1)

    # continuation
    assert refine((-1)**((-1)**x/2 - S.Half), Q.integer(x)) == (-1)**x
    assert refine((-1)**((-1)**x/2 + S.Half), Q.integer(x)) == (-1)**(x + 1)
    assert refine((-1)**((-1)**x/2 + 5*S.Half), Q.integer(x)) == (-1)**(x + 1)
Exemple #2
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def test_re():
    assert refine(re(x), Q.real(x)) == x
    assert refine(re(x), Q.imaginary(x)) is S.Zero
    assert refine(re(x+y), Q.real(x) & Q.real(y)) == x + y
    assert refine(re(x+y), Q.real(x) & Q.imaginary(y)) == x
    assert refine(re(x*y), Q.real(x) & Q.real(y)) == x * y
    assert refine(re(x*y), Q.real(x) & Q.imaginary(y)) == 0
    assert refine(re(x*y*z), Q.real(x) & Q.real(y) & Q.real(z)) == x * y * z
Exemple #3
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def _(expr):
    return [allarg(x, Q.positive(x), expr) >> Q.positive(expr),
            allarg(x, Q.negative(x), expr) >> Q.negative(expr),
            allarg(x, Q.real(x), expr) >> Q.real(expr),
            allarg(x, Q.rational(x), expr) >> Q.rational(expr),
            allarg(x, Q.integer(x), expr) >> Q.integer(expr),
            exactlyonearg(x, ~Q.integer(x), expr) >> ~Q.integer(expr),
            ]
Exemple #4
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def test_pow2():
    assert refine((-1)**((-1)**x/2 - 7*S.Half), Q.integer(x)) == (-1)**(x + 1)
    assert refine((-1)**((-1)**x/2 - 9*S.Half), Q.integer(x)) == (-1)**x

    # powers of Abs
    assert refine(Abs(x)**2, Q.real(x)) == x**2
    assert refine(Abs(x)**3, Q.real(x)) == Abs(x)**3
    assert refine(Abs(x)**2) == Abs(x)**2
Exemple #5
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def _(expr):
    return [Equivalent(Q.zero(expr), anyarg(x, Q.zero(x), expr)),
            allarg(x, Q.positive(x), expr) >> Q.positive(expr),
            allarg(x, Q.real(x), expr) >> Q.real(expr),
            allarg(x, Q.rational(x), expr) >> Q.rational(expr),
            allarg(x, Q.integer(x), expr) >> Q.integer(expr),
            exactlyonearg(x, ~Q.rational(x), expr) >> ~Q.integer(expr),
            allarg(x, Q.commutative(x), expr) >> Q.commutative(expr),
            ]
Exemple #6
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def test_im():
    assert refine(im(x), Q.imaginary(x)) == -I*x
    assert refine(im(x), Q.real(x)) is S.Zero
    assert refine(im(x+y), Q.imaginary(x) & Q.imaginary(y)) == -I*x - I*y
    assert refine(im(x+y), Q.real(x) & Q.imaginary(y)) == -I*y
    assert refine(im(x*y), Q.imaginary(x) & Q.real(y)) == -I*x*y
    assert refine(im(x*y), Q.imaginary(x) & Q.imaginary(y)) == 0
    assert refine(im(1/x), Q.imaginary(x)) == -I/x
    assert refine(im(x*y*z), Q.imaginary(x) & Q.imaginary(y)
        & Q.imaginary(z)) == -I*x*y*z
Exemple #7
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def test_pow_pos_neg():
    assert satask(Q.nonnegative(x**2), Q.positive(x)) is True
    assert satask(Q.nonpositive(x**2), Q.positive(x)) is False
    assert satask(Q.positive(x**2), Q.positive(x)) is True
    assert satask(Q.negative(x**2), Q.positive(x)) is False
    assert satask(Q.real(x**2), Q.positive(x)) is True

    assert satask(Q.nonnegative(x**2), Q.negative(x)) is True
    assert satask(Q.nonpositive(x**2), Q.negative(x)) is False
    assert satask(Q.positive(x**2), Q.negative(x)) is True
    assert satask(Q.negative(x**2), Q.negative(x)) is False
    assert satask(Q.real(x**2), Q.negative(x)) is True

    assert satask(Q.nonnegative(x**2), Q.nonnegative(x)) is True
    assert satask(Q.nonpositive(x**2), Q.nonnegative(x)) is None
    assert satask(Q.positive(x**2), Q.nonnegative(x)) is None
    assert satask(Q.negative(x**2), Q.nonnegative(x)) is False
    assert satask(Q.real(x**2), Q.nonnegative(x)) is True

    assert satask(Q.nonnegative(x**2), Q.nonpositive(x)) is True
    assert satask(Q.nonpositive(x**2), Q.nonpositive(x)) is None
    assert satask(Q.positive(x**2), Q.nonpositive(x)) is None
    assert satask(Q.negative(x**2), Q.nonpositive(x)) is False
    assert satask(Q.real(x**2), Q.nonpositive(x)) is True

    assert satask(Q.nonnegative(x**3), Q.positive(x)) is True
    assert satask(Q.nonpositive(x**3), Q.positive(x)) is False
    assert satask(Q.positive(x**3), Q.positive(x)) is True
    assert satask(Q.negative(x**3), Q.positive(x)) is False
    assert satask(Q.real(x**3), Q.positive(x)) is True

    assert satask(Q.nonnegative(x**3), Q.negative(x)) is False
    assert satask(Q.nonpositive(x**3), Q.negative(x)) is True
    assert satask(Q.positive(x**3), Q.negative(x)) is False
    assert satask(Q.negative(x**3), Q.negative(x)) is True
    assert satask(Q.real(x**3), Q.negative(x)) is True

    assert satask(Q.nonnegative(x**3), Q.nonnegative(x)) is True
    assert satask(Q.nonpositive(x**3), Q.nonnegative(x)) is None
    assert satask(Q.positive(x**3), Q.nonnegative(x)) is None
    assert satask(Q.negative(x**3), Q.nonnegative(x)) is False
    assert satask(Q.real(x**3), Q.nonnegative(x)) is True

    assert satask(Q.nonnegative(x**3), Q.nonpositive(x)) is None
    assert satask(Q.nonpositive(x**3), Q.nonpositive(x)) is True
    assert satask(Q.positive(x**3), Q.nonpositive(x)) is False
    assert satask(Q.negative(x**3), Q.nonpositive(x)) is None
    assert satask(Q.real(x**3), Q.nonpositive(x)) is True

    # If x is zero, x**negative is not real.
    assert satask(Q.nonnegative(x**-2), Q.nonpositive(x)) is None
    assert satask(Q.nonpositive(x**-2), Q.nonpositive(x)) is None
    assert satask(Q.positive(x**-2), Q.nonpositive(x)) is None
    assert satask(Q.negative(x**-2), Q.nonpositive(x)) is None
    assert satask(Q.real(x**-2), Q.nonpositive(x)) is None
Exemple #8
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def test_refine():
    # relational
    assert not refine(x < 0, ~Q.is_true(x < 0))
    assert refine(x < 0, Q.is_true(x < 0))
    assert refine(x < 0, Q.is_true(0 > x)) == True
    assert refine(x < 0, Q.is_true(y < 0)) == (x < 0)
    assert not refine(x <= 0, ~Q.is_true(x <= 0))
    assert refine(x <= 0,  Q.is_true(x <= 0))
    assert refine(x <= 0,  Q.is_true(0 >= x)) == True
    assert refine(x <= 0,  Q.is_true(y <= 0)) == (x <= 0)
    assert not refine(x > 0, ~Q.is_true(x > 0))
    assert refine(x > 0,  Q.is_true(x > 0))
    assert refine(x > 0,  Q.is_true(0 < x)) == True
    assert refine(x > 0,  Q.is_true(y > 0)) == (x > 0)
    assert not refine(x >= 0, ~Q.is_true(x >= 0))
    assert refine(x >= 0,  Q.is_true(x >= 0))
    assert refine(x >= 0,  Q.is_true(0 <= x)) == True
    assert refine(x >= 0,  Q.is_true(y >= 0)) == (x >= 0)
    assert not refine(Eq(x, 0), ~Q.is_true(Eq(x, 0)))
    assert refine(Eq(x, 0),  Q.is_true(Eq(x, 0)))
    assert refine(Eq(x, 0),  Q.is_true(Eq(0, x))) == True
    assert refine(Eq(x, 0),  Q.is_true(Eq(y, 0))) == Eq(x, 0)
    assert not refine(Ne(x, 0), ~Q.is_true(Ne(x, 0)))
    assert refine(Ne(x, 0), Q.is_true(Ne(0, x))) == True
    assert refine(Ne(x, 0),  Q.is_true(Ne(x, 0)))
    assert refine(Ne(x, 0),  Q.is_true(Ne(y, 0))) == (Ne(x, 0))

    # boolean functions
    assert refine(And(x > 0, y > 0), Q.is_true(x > 0)) == (y > 0)
    assert refine(And(x > 0, y > 0), Q.is_true(x > 0) & Q.is_true(y > 0)) == True

    # predicates
    assert refine(Q.positive(x), Q.positive(x)) == True
    assert refine(Q.positive(x), Q.negative(x)) == False
    assert refine(Q.positive(x), Q.real(x)) == Q.positive(x)
Exemple #9
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def test_field_assumptions():
    X = MatrixSymbol('X', 4, 4)
    Y = MatrixSymbol('Y', 4, 4)
    assert ask(Q.real_elements(X), Q.real_elements(X))
    assert not ask(Q.integer_elements(X), Q.real_elements(X))
    assert ask(Q.complex_elements(X), Q.real_elements(X))
    assert ask(Q.complex_elements(X**2), Q.real_elements(X))
    assert ask(Q.real_elements(X**2), Q.integer_elements(X))
    assert ask(Q.real_elements(X + Y), Q.real_elements(X)) is None
    assert ask(Q.real_elements(X + Y), Q.real_elements(X) & Q.real_elements(Y))
    from sympy.matrices.expressions.hadamard import HadamardProduct
    assert ask(Q.real_elements(HadamardProduct(X, Y)),
               Q.real_elements(X) & Q.real_elements(Y))
    assert ask(Q.complex_elements(X + Y),
               Q.real_elements(X) & Q.complex_elements(Y))

    assert ask(Q.real_elements(X.T), Q.real_elements(X))
    assert ask(Q.real_elements(X.I), Q.real_elements(X) & Q.invertible(X))
    assert ask(Q.real_elements(Trace(X)), Q.real_elements(X))
    assert ask(Q.integer_elements(Determinant(X)), Q.integer_elements(X))
    assert not ask(Q.integer_elements(X.I), Q.integer_elements(X))
    alpha = Symbol('alpha')
    assert ask(Q.real_elements(alpha * X), Q.real_elements(X) & Q.real(alpha))
    assert ask(Q.real_elements(LofLU(X)), Q.real_elements(X))
    e = Symbol('e', integer=True, negative=True)
    assert ask(Q.real_elements(X**e), Q.real_elements(X) & Q.invertible(X))
    assert ask(Q.real_elements(X**e), Q.real_elements(X)) is None
Exemple #10
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def _(expr):
    base, exp = expr.base, expr.exp
    return [
        (Q.real(base) & Q.even(exp) & Q.nonnegative(exp)) >> Q.nonnegative(expr),
        (Q.nonnegative(base) & Q.odd(exp) & Q.nonnegative(exp)) >> Q.nonnegative(expr),
        (Q.nonpositive(base) & Q.odd(exp) & Q.nonnegative(exp)) >> Q.nonpositive(expr),
        Equivalent(Q.zero(expr), Q.zero(base) & Q.positive(exp))
    ]
Exemple #11
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def test_Abs():
    assert refine(Abs(x), Q.positive(x)) == x
    assert refine(1 + Abs(x), Q.positive(x)) == 1 + x
    assert refine(Abs(x), Q.negative(x)) == -x
    assert refine(1 + Abs(x), Q.negative(x)) == 1 - x

    assert refine(Abs(x**2)) != x**2
    assert refine(Abs(x**2), Q.real(x)) == x**2
Exemple #12
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def test_atan2():
    assert refine(atan2(y, x), Q.real(y) & Q.positive(x)) == atan(y/x)
    assert refine(atan2(y, x), Q.negative(y) & Q.positive(x)) == atan(y/x)
    assert refine(atan2(y, x), Q.negative(y) & Q.negative(x)) == atan(y/x) - pi
    assert refine(atan2(y, x), Q.positive(y) & Q.negative(x)) == atan(y/x) + pi
    assert refine(atan2(y, x), Q.zero(y) & Q.negative(x)) == pi
    assert refine(atan2(y, x), Q.positive(y) & Q.zero(x)) == pi/2
    assert refine(atan2(y, x), Q.negative(y) & Q.zero(x)) == -pi/2
    assert refine(atan2(y, x), Q.zero(y) & Q.zero(x)) is nan
Exemple #13
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def test_matrix_element_sets():
    X = MatrixSymbol('X', 4, 4)
    assert ask(Q.real(X[1, 2]), Q.real_elements(X))
    assert ask(Q.integer(X[1, 2]), Q.integer_elements(X))
    assert ask(Q.complex(X[1, 2]), Q.complex_elements(X))
    assert ask(Q.integer_elements(Identity(3)))
    assert ask(Q.integer_elements(ZeroMatrix(3, 3)))
    assert ask(Q.integer_elements(OneMatrix(3, 3)))
    from sympy.matrices.expressions.fourier import DFT
    assert ask(Q.complex_elements(DFT(3)))
Exemple #14
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def test_imaginary():
    assert satask(Q.imaginary(2*I)) is True
    assert satask(Q.imaginary(x*y), Q.imaginary(x)) is None
    assert satask(Q.imaginary(x*y), Q.imaginary(x) & Q.real(y)) is True
    assert satask(Q.imaginary(x), Q.real(x)) is False
    assert satask(Q.imaginary(1)) is False
    assert satask(Q.imaginary(x*y), Q.real(x) & Q.real(y)) is False
    assert satask(Q.imaginary(x + y), Q.real(x) & Q.real(y)) is False
Exemple #15
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    def _contains(self, other):
        from sympy.assumptions.ask import ask, Q
        if ask(Q.real(other)) is False:
            return False

        if self.left_open:
            expr = other > self.start
        else:
            expr = other >= self.start

        if self.right_open:
            expr = And(expr, other < self.end)
        else:
            expr = And(expr, other <= self.end)

        return expr
Exemple #16
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    def _contains(self, other):
        from sympy.assumptions.ask import ask, Q
        if ask(Q.real(other)) is False:
            return False

        if self.left_open:
            expr = other > self.start
        else:
            expr = other >= self.start

        if self.right_open:
            expr = And(expr, other < self.end)
        else:
            expr = And(expr, other <= self.end)

        return expr
Exemple #17
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def test_call():
    x, y = symbols('x y')
    # See the long history of this in issues 5026 and 5105.

    raises(TypeError, lambda: sin(x)({x: 1, sin(x): 2}))
    raises(TypeError, lambda: sin(x)(1))

    # No effect as there are no callables
    assert sin(x).rcall(1) == sin(x)
    assert (1 + sin(x)).rcall(1) == 1 + sin(x)

    # Effect in the pressence of callables
    l = Lambda(x, 2 * x)
    assert (l + x).rcall(y) == 2 * y + x
    assert (x**l).rcall(2) == x**4
    # TODO UndefinedFunction does not subclass Expr
    #f = Function('f')
    #assert (2*f)(x) == 2*f(x)

    assert (Q.real & Q.positive).rcall(x) == Q.real(x) & Q.positive(x)
Exemple #18
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def test_real():
    assert satask(Q.real(x*y), Q.real(x) & Q.real(y)) is True
    assert satask(Q.real(x + y), Q.real(x) & Q.real(y)) is True
    assert satask(Q.real(x*y*z), Q.real(x) & Q.real(y) & Q.real(z)) is True
    assert satask(Q.real(x*y*z), Q.real(x) & Q.real(y)) is None
    assert satask(Q.real(x*y*z), Q.real(x) & Q.real(y) & Q.imaginary(z)) is False
    assert satask(Q.real(x + y + z), Q.real(x) & Q.real(y) & Q.real(z)) is True
    assert satask(Q.real(x + y + z), Q.real(x) & Q.real(y)) is None
Exemple #19
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def test_non_atoms():
    assert ask(Q.real(Trace(X)), Q.positive(Trace(X)))
Exemple #20
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def test_complex():
    assert refine(re(1/(x + I*y)), Q.real(x) & Q.real(y)) == \
        x/(x**2 + y**2)
    assert refine(im(1/(x + I*y)), Q.real(x) & Q.real(y)) == \
        -y/(x**2 + y**2)
    assert refine(re((w + I*x) * (y + I*z)), Q.real(w) & Q.real(x) & Q.real(y)
        & Q.real(z)) == w*y - x*z
    assert refine(im((w + I*x) * (y + I*z)), Q.real(w) & Q.real(x) & Q.real(y)
        & Q.real(z)) == w*z + x*y
Exemple #21
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def test_satask():
    # No relevant facts
    assert satask(Q.real(x), Q.real(x)) is True
    assert satask(Q.real(x), ~Q.real(x)) is False
    assert satask(Q.real(x)) is None

    assert satask(Q.real(x), Q.positive(x)) is True
    assert satask(Q.positive(x), Q.real(x)) is None
    assert satask(Q.real(x), ~Q.positive(x)) is None
    assert satask(Q.positive(x), ~Q.real(x)) is False

    raises(ValueError, lambda: satask(Q.real(x), Q.real(x) & ~Q.real(x)))

    with assuming(Q.positive(x)):
        assert satask(Q.real(x)) is True
        assert satask(~Q.positive(x)) is False
        raises(ValueError, lambda: satask(Q.real(x), ~Q.positive(x)))

    assert satask(Q.zero(x), Q.nonzero(x)) is False
    assert satask(Q.positive(x), Q.zero(x)) is False
    assert satask(Q.real(x), Q.zero(x)) is True
    assert satask(Q.zero(x), Q.zero(x*y)) is None
    assert satask(Q.zero(x*y), Q.zero(x))
Exemple #22
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def _(expr):
    allargs_real = allargs(x, Q.real(x), expr)
    onearg_irrational = exactlyonearg(x, Q.irrational(x), expr)
    return Implies(allargs_real, Implies(onearg_irrational,
                                         Q.irrational(expr)))

def register_fact(klass, fact, registry=fact_registry):
    registry[klass] |= {fact}


for klass, fact in [
    (Mul, Equivalent(Q.zero, AnyArgs(Q.zero))),
    (MatMul, Implies(AllArgs(Q.square), Equivalent(Q.invertible, AllArgs(Q.invertible)))),
    (Add, Implies(AllArgs(Q.positive), Q.positive)),
    (Add, Implies(AllArgs(Q.negative), Q.negative)),
    (Mul, Implies(AllArgs(Q.positive), Q.positive)),
    (Mul, Implies(AllArgs(Q.commutative), Q.commutative)),
    (Mul, Implies(AllArgs(Q.real), Q.commutative)),

    (Pow, CustomLambda(lambda power: Implies(Q.real(power.base) &
    Q.even(power.exp) & Q.nonnegative(power.exp), Q.nonnegative(power)))),
    (Pow, CustomLambda(lambda power: Implies(Q.nonnegative(power.base) & Q.odd(power.exp) & Q.nonnegative(power.exp), Q.nonnegative(power)))),
    (Pow, CustomLambda(lambda power: Implies(Q.nonpositive(power.base) & Q.odd(power.exp) & Q.nonnegative(power.exp), Q.nonpositive(power)))),

    # This one can still be made easier to read. I think we need basic pattern
    # matching, so that we can just write Equivalent(Q.zero(x**y), Q.zero(x) & Q.positive(y))
    (Pow, CustomLambda(lambda power: Equivalent(Q.zero(power), Q.zero(power.base) & Q.positive(power.exp)))),
    (Integer, CheckIsPrime(Q.prime)),
    # Implicitly assumes Mul has more than one arg
    # Would be AllArgs(Q.prime | Q.composite) except 1 is composite
    (Mul, Implies(AllArgs(Q.prime), ~Q.prime)),
    # More advanced prime assumptions will require inequalities, as 1 provides
    # a corner case.
    (Mul, Implies(AllArgs(Q.imaginary | Q.real), Implies(ExactlyOneArg(Q.imaginary), Q.imaginary))),
    (Mul, Implies(AllArgs(Q.real), Q.real)),
Exemple #24
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def register_fact(klass, fact, registry=fact_registry):
    registry[klass] |= {fact}


for klass, fact in [
    (Mul, Equivalent(Q.zero, AnyArgs(Q.zero))),
    (MatMul, Implies(AllArgs(Q.square), Equivalent(Q.invertible, AllArgs(Q.invertible)))),
    (Add, Implies(AllArgs(Q.positive), Q.positive)),
    (Add, Implies(AllArgs(Q.negative), Q.negative)),
    (Mul, Implies(AllArgs(Q.positive), Q.positive)),
    (Mul, Implies(AllArgs(Q.commutative), Q.commutative)),
    (Mul, Implies(AllArgs(Q.real), Q.commutative)),

    (Pow, CustomLambda(lambda power: Implies(Q.real(power.base) &
    Q.even(power.exp) & Q.nonnegative(power.exp), Q.nonnegative(power)))),
    (Pow, CustomLambda(lambda power: Implies(Q.nonnegative(power.base) & Q.odd(power.exp) & Q.nonnegative(power.exp), Q.nonnegative(power)))),
    (Pow, CustomLambda(lambda power: Implies(Q.nonpositive(power.base) & Q.odd(power.exp) & Q.nonnegative(power.exp), Q.nonpositive(power)))),

    # This one can still be made easier to read. I think we need basic pattern
    # matching, so that we can just write Equivalent(Q.zero(x**y), Q.zero(x) & Q.positive(y))
    (Pow, CustomLambda(lambda power: Equivalent(Q.zero(power), Q.zero(power.base) & Q.positive(power.exp)))),
    (Integer, CheckIsPrime(Q.prime)),
    # Implicitly assumes Mul has more than one arg
    # Would be AllArgs(Q.prime | Q.composite) except 1 is composite
    (Mul, Implies(AllArgs(Q.prime), ~Q.prime)),
    # More advanced prime assumptions will require inequalities, as 1 provides
    # a corner case.
    (Mul, Implies(AllArgs(Q.imaginary | Q.real), Implies(ExactlyOneArg(Q.imaginary), Q.imaginary))),
    (Mul, Implies(AllArgs(Q.real), Q.real)),
Exemple #25
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    registry[klass] |= {fact}


for klass, fact in [
    (Mul, Equivalent(Q.zero, AnyArgs(Q.zero))),
    (MatMul,
     Implies(AllArgs(Q.square), Equivalent(Q.invertible,
                                           AllArgs(Q.invertible)))),
    (Add, Implies(AllArgs(Q.positive), Q.positive)),
    (Add, Implies(AllArgs(Q.negative), Q.negative)),
    (Mul, Implies(AllArgs(Q.positive), Q.positive)),
    (Mul, Implies(AllArgs(Q.commutative), Q.commutative)),
    (Mul, Implies(AllArgs(Q.real), Q.commutative)),
    (Pow,
     CustomLambda(lambda power: Implies(
         Q.real(power.base) & Q.even(power.exp) & Q.nonnegative(power.exp),
         Q.nonnegative(power)))),
    (Pow,
     CustomLambda(lambda power: Implies(
         Q.nonnegative(power.base) & Q.odd(power.exp) & Q.nonnegative(
             power.exp), Q.nonnegative(power)))),
    (Pow,
     CustomLambda(lambda power: Implies(
         Q.nonpositive(power.base) & Q.odd(power.exp) & Q.nonnegative(
             power.exp), Q.nonpositive(power)))),

        # This one can still be made easier to read. I think we need basic pattern
        # matching, so that we can just write Equivalent(Q.zero(x**y), Q.zero(x) & Q.positive(y))
    (Pow,
     CustomLambda(
         lambda power: Equivalent(Q.zero(power),
Exemple #26
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def _(expr):
    # General Case: Odd number of imaginary args implies mul is imaginary(To be implemented)
    allargs_imag_or_real = allargs(x, Q.imaginary(x) | Q.real(x), expr)
    onearg_imaginary = exactlyonearg(x, Q.imaginary(x), expr)
    return Implies(allargs_imag_or_real,
                   Implies(onearg_imaginary, Q.imaginary(expr)))
Exemple #27
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def get_known_facts(x=None):
    """
    Facts between unary predicates.

    Parameters
    ==========

    x : Symbol, optional
        Placeholder symbol for unary facts. Default is ``Symbol('x')``.

    Returns
    =======

    fact : Known facts in conjugated normal form.

    """
    if x is None:
        x = Symbol('x')

    fact = And(
        # primitive predicates for extended real exclude each other.
        Exclusive(Q.negative_infinite(x), Q.negative(x), Q.zero(x),
                  Q.positive(x), Q.positive_infinite(x)),

        # build complex plane
        Exclusive(Q.real(x), Q.imaginary(x)),
        Implies(Q.real(x) | Q.imaginary(x), Q.complex(x)),

        # other subsets of complex
        Exclusive(Q.transcendental(x), Q.algebraic(x)),
        Equivalent(Q.real(x),
                   Q.rational(x) | Q.irrational(x)),
        Exclusive(Q.irrational(x), Q.rational(x)),
        Implies(Q.rational(x), Q.algebraic(x)),

        # integers
        Exclusive(Q.even(x), Q.odd(x)),
        Implies(Q.integer(x), Q.rational(x)),
        Implies(Q.zero(x), Q.even(x)),
        Exclusive(Q.composite(x), Q.prime(x)),
        Implies(Q.composite(x) | Q.prime(x),
                Q.integer(x) & Q.positive(x)),
        Implies(Q.even(x) & Q.positive(x) & ~Q.prime(x), Q.composite(x)),

        # hermitian and antihermitian
        Implies(Q.real(x), Q.hermitian(x)),
        Implies(Q.imaginary(x), Q.antihermitian(x)),
        Implies(Q.zero(x),
                Q.hermitian(x) | Q.antihermitian(x)),

        # define finity and infinity, and build extended real line
        Exclusive(Q.infinite(x), Q.finite(x)),
        Implies(Q.complex(x), Q.finite(x)),
        Implies(
            Q.negative_infinite(x) | Q.positive_infinite(x), Q.infinite(x)),

        # commutativity
        Implies(Q.finite(x) | Q.infinite(x), Q.commutative(x)),

        # matrices
        Implies(Q.orthogonal(x), Q.positive_definite(x)),
        Implies(Q.orthogonal(x), Q.unitary(x)),
        Implies(Q.unitary(x) & Q.real_elements(x), Q.orthogonal(x)),
        Implies(Q.unitary(x), Q.normal(x)),
        Implies(Q.unitary(x), Q.invertible(x)),
        Implies(Q.normal(x), Q.square(x)),
        Implies(Q.diagonal(x), Q.normal(x)),
        Implies(Q.positive_definite(x), Q.invertible(x)),
        Implies(Q.diagonal(x), Q.upper_triangular(x)),
        Implies(Q.diagonal(x), Q.lower_triangular(x)),
        Implies(Q.lower_triangular(x), Q.triangular(x)),
        Implies(Q.upper_triangular(x), Q.triangular(x)),
        Implies(Q.triangular(x),
                Q.upper_triangular(x) | Q.lower_triangular(x)),
        Implies(Q.upper_triangular(x) & Q.lower_triangular(x), Q.diagonal(x)),
        Implies(Q.diagonal(x), Q.symmetric(x)),
        Implies(Q.unit_triangular(x), Q.triangular(x)),
        Implies(Q.invertible(x), Q.fullrank(x)),
        Implies(Q.invertible(x), Q.square(x)),
        Implies(Q.symmetric(x), Q.square(x)),
        Implies(Q.fullrank(x) & Q.square(x), Q.invertible(x)),
        Equivalent(Q.invertible(x), ~Q.singular(x)),
        Implies(Q.integer_elements(x), Q.real_elements(x)),
        Implies(Q.real_elements(x), Q.complex_elements(x)),
    )
    return fact