Exemplo n.º 1
0
def frexp(x):
    """
    Version of frexp that works for numbers with uncertainty, and also
    for regular numbers.
    """

    # The code below is inspired by uncert_core.wrap().  It is
    # simpler because only 1 argument is given, and there is no
    # delegation to other functions involved (as for __mul__, etc.).

    aff_func = to_affine_scalar(x)

    if aff_func._linear_part:
        (mantissa, exponent) = math.frexp(aff_func.nominal_value)
        return (
            AffineScalarFunc(
                mantissa,
                # With frexp(x) = (m, e), x = m*2**e, so m = x*2**-e
                # and therefore dm/dx = 2**-e (as e in an integer that
                # does not vary when x changes):
                LinearCombination([2**-exponent, aff_func._linear_part])),
            # The exponent is an integer and is supposed to be
            # continuous (errors must be small):
            exponent)
    else:
        # This function was not called with an AffineScalarFunc
        # argument: there is no need to return numbers with uncertainties:
        return math.frexp(x)
Exemplo n.º 2
0
 def rebin(self, x_rebin_fact, y_rebin_fact):
     """ Rebin the data and adjust dims """
     if self.data == None:
         raise Exception('Please read in the file you wish to rebin first')
     (mantis_x, exp_x) = math.frexp(x_rebin_fact)
     (mantis_y, exp_y) = math.frexp(y_rebin_fact)
     # FIXME - this is a floating point comparison, is it always exact?
     if (mantis_x != 0.5 or mantis_y != 0.5):
         raise Exception('Rebin factors not power of 2 not supported (yet)')
     if int(self.dim1 / x_rebin_fact) * x_rebin_fact != self.dim1 or \
        int(self.dim2 / x_rebin_fact) * x_rebin_fact != self.dim2 :
         raise('image size is not divisible by rebin factor - ' + \
               'skipping rebin')
     pass  ## self.data.savespace(1) # avoid the upcasting behaviour
     i = 1
     while i < x_rebin_fact:
         # FIXME - why do you divide by 2? Rebinning should increase counts?
         self.data = ((self.data[:, ::2] + self.data[:, 1::2]) / 2)
         i = i * 2
     i = 1
     while i < y_rebin_fact:
         self.data = ((self.data[::2, :] + self.data[1::2, :]) / 2)
         i = i * 2
     self.resetvals()
     self.dim1 = self.dim1 / x_rebin_fact
     self.dim2 = self.dim2 / y_rebin_fact
     #update header
     self.update_header()
Exemplo n.º 3
0
def frexp(x):
    """
    Version of frexp that works for numbers with uncertainty, and also
    for regular numbers.
    """

    # The code below is inspired by uncertainties.wrap().  It is
    # simpler because only 1 argument is given, and there is no
    # delegation to other functions involved (as for __mul__, etc.).

    aff_func = to_affine_scalar(x)

    if aff_func.derivatives:
        result = math.frexp(aff_func.nominal_value)
        # With frexp(x) = (m, e), dm/dx = 1/(2**e):
        factor = 1/(2**result[1])
        return (
            AffineScalarFunc(
                result[0],
                # Chain rule:
                dict([(var, factor*deriv)
                      for (var, deriv) in aff_func.derivatives.iteritems()])),
            # The exponent is an integer and is supposed to be
            # continuous (small errors):
            result[1])
    else:
        # This function was not called with an AffineScalarFunc
        # argument: there is no need to return numbers with uncertainties:
        return math.frexp(x)
Exemplo n.º 4
0
def _product(values):
    """Return product of values as (exponent, mantissa)."""
    errmsg = 'mixed Decimal and float is not supported'
    prod = 1
    for x in values:
        if isinstance(x, float):
            break
        prod *= x
    else:
        return (0, prod)
    if isinstance(prod, Decimal):
        raise TypeError(errmsg)
    # Since floats can overflow easily, we calculate the product as a
    # sort of poor-man's BigFloat. Given that:
    #
    #   x = 2**p * m  # p == power or exponent (scale), m = mantissa
    #
    # we can calculate the product of two (or more) x values as:
    #
    #   x1*x2 = 2**p1*m1 * 2**p2*m2 = 2**(p1+p2)*(m1*m2)
    #
    mant, scale = 1, 0  #math.frexp(prod)  # FIXME
    for y in chain([x], values):
        if isinstance(y, Decimal):
            raise TypeError(errmsg)
        m1, e1 = math.frexp(y)
        m2, e2 = math.frexp(mant)
        scale += (e1 + e2)
        mant = m1*m2
    return (scale, mant)
Exemplo n.º 5
0
def nearly_equal(float1, float2, places=15):
    """
    Determines whether two floating point numbers are nearly equal (to
    within reasonable rounding errors
    """
    mantissa1, exp1 = math.frexp(float1)
    mantissa2, exp2 = math.frexp(float2)
    return (round(mantissa1, places) == round(mantissa2, places) and
            exp1 == exp2)
Exemplo n.º 6
0
    def __init__(self, L):

        self.L = L
        if math.frexp(self.L)[0]!=0.5:
            print "profile size is not a power of 2"
            pdb.set_trace()

        self.J = math.frexp(self.L)[1]-1
        self.data = False
        self.value = dict()
Exemplo n.º 7
0
 def _not_nearly_equal(self, float1, float2):
     """
     Determines whether two floating point numbers are nearly equal (to
     within reasonable rounding errors
     """
     mantissa1, exp1 = math.frexp(float1)
     mantissa2, exp2 = math.frexp(float2)
     return not ((round(mantissa1, self.nearly_equal_places) ==
                  round(mantissa2, self.nearly_equal_places)) and
                 exp1 == exp2)
Exemplo n.º 8
0
    def SetFog(self,fog):
        projection = (fog.function >> 3) & 1

        if projection:
            if fog.z_far == fog.z_near or fog.z_end == fog.z_start:
                A = 0
                C = 0
            else:
                A = (fog.z_far - fog.z_near)/(fog.z_end - fog.z_start)
                C = (fog.z_start - fog.z_near)/(fog.z_end - fog.z_start)
            b_shift = 0
            b_magnitude = 0

        else:
            if fog.z_far == fog.z_near or fog.z_end == fog.z_start:
                A = 0
                B = 0.5
                C = 0
            else:
                A = fog.z_far*fog.z_near/((fog.z_far - fog.z_near)*(fog.z_end - fog.z_start))
                B = fog.z_far/(fog.z_far - fog.z_near)
                C = fog.z_start/(fog.z_end - fog.z_start)

            if B > 1:
                b_shift = 1 + int(ceil(log(B,2)))
            elif 0 < B < 0.5:
                b_shift = 0
            else:
                b_shift = 1

            A /= 2**b_shift
            b_magnitude = int(2*(B/2**b_shift)*8388638)


        a_mantissa,a_exponent = frexp(A)
        self.fog_param0[0:11] = int(abs(a_mantissa)*2**12) & 0x7FF
        self.fog_param0[11:19] = a_exponent + 126 if A != 0 else 0
        self.fog_param0[19] = a_mantissa < 0

        self.fog_param1[0:24] = b_magnitude
        self.fog_param2[0:5] = b_shift

        c_mantissa,c_exponent = frexp(C)
        self.fog_param3[0:11] = int(abs(c_mantissa)*2**12) & 0x7FF
        self.fog_param3[11:19] = c_exponent + 126 if C != 0 else 0
        self.fog_param3[19] = c_mantissa < 0
        self.fog_param3[20:21] = projection
        self.fog_param3[21:24] = fog.function

        self.fog_color[0:8] = fog.color.b
        self.fog_color[8:16] = fog.color.g
        self.fog_color[16:24] = fog.color.r
Exemplo n.º 9
0
	def __new__(cls, *args):
		if len(args) == 0:
			self = bytes.__new__(cls)
			self._pad = 0
		elif len(args) == 1:
			if isinstance(args[0], IntType):
				self = bytes.__new__(cls, uitob(args[0]))
			else:
				self = bytes.__new__(cls, args[0])
			self._pad = 0
		elif len(args) == 2:
			if isinstance(args[0], str):
				arg = int(args[0], args[1])
				m, e = math.frexp(args[1])
				bpd = e - (1 if m == 0.5 else 0)
				bitlen = len(args[0]) * bpd # num digits * bits per digit
				shift = ((bitlen + 7) & ~7) - bitlen
				self = bytes.__new__(cls, uitob(arg << shift))
				self._pad = shift & 7
			else:
				self = bytes.__new__(cls, args[1])
				self._pad = args[0]
				if pad > 7 or (pad and not self):
					raise ValueError('invalid pad value')
		else:
			raise TypeError('BitString constructor takes 1 or 2 args')
		return self
Exemplo n.º 10
0
 def test_builtin_math_frexp(self):
     import math
     def fn(f):
         return math.frexp(f)
     res = self.interpret(fn, [10/3.0])
     mantissa, exponent = math.frexp(10/3.0)        
     assert self.float_eq(res.item0, mantissa) and self.float_eq(res.item1, exponent)
Exemplo n.º 11
0
def log2(x):
    # Uses an algorithm that should:
    #   (a) produce exact results for powers of 2, and
    #   (b) be monotonic, assuming that the system log is monotonic.
    if not isfinite(x):
        if isnan(x):
            return x  # log2(nan) = nan
        elif x > 0.0:
            return x  # log2(+inf) = +inf
        else:
            # log2(-inf) = nan, invalid-operation
            raise ValueError("math domain error")

    if x > 0.0:
        if 0:  # HAVE_LOG2
            return math.log2(x)
        m, e = math.frexp(x)
        # We want log2(m * 2**e) == log(m) / log(2) + e.  Care is needed when
        # x is just greater than 1.0: in that case e is 1, log(m) is negative,
        # and we get significant cancellation error from the addition of
        # log(m) / log(2) to e.  The slight rewrite of the expression below
        # avoids this problem.
        if x >= 1.0:
            return math.log(2.0 * m) / math.log(2.0) + (e - 1)
        else:
            return math.log(m) / math.log(2.0) + e
    else:
        raise ValueError("math domain error")
Exemplo n.º 12
0
	def evaluate_func(next_func):

		if next_func[0] == 'x':
			return x
		elif next_func[0] == 'y':
			return y

		elif next_func[0] == 'abs':
			return abs(evaluate_func(next_func[1]))
		elif next_func[0] == 'cos_pi':
			return cos(pi*evaluate_func(next_func[1]))
		elif next_func[0] == 'sin_pi':
			return sin(pi*evaluate_func(next_func[1]))
		elif next_func[0] == 'sqrt':
			return sqrt(abs(pi*evaluate_func(next_func[1])))
		elif next_func[0] == 'diff':
			return evaluate_func(next_func[1])-evaluate_func(next_func[2])
		elif next_func[0] == 'ave':
			return (evaluate_func(next_func[1])+evaluate_func(next_func[2]))/2.0
		elif next_func[0] == 'prod':
			return evaluate_func(next_func[1])*evaluate_func(next_func[2])
		elif next_func[0] == 'frexp':
			return frexp(evaluate_func(next_func[1]))[0]
		elif next_func[0] == 'x':
			return evaluate_func(next_func[1])
		elif next_func[0] == 'y':
			return evaluate_func(next_func[2])
Exemplo n.º 13
0
def rank_sum_n_sites(measurements, details=False):
    if math.frexp(len(measurements))[0] != 0.5:
        print("rank_sum_n_sites received an input of length %s, which is not equal to the number of genotypes."
              "Quitting." % len(measurements))
        sys.exit()
    output_indices = []
    for genotype in measurements:
        output_indices.append(measurements.keys().index(genotype))
    done = False
    while not done:
        done = True
        for i in range(len(measurements) - 1):
            if ranksums(measurements[measurements.keys()[output_indices[i]]],
                        measurements[measurements.keys()[output_indices[i+1]]])[0] < 0:
                output_indices[i], output_indices[i + 1] = output_indices[i + 1], output_indices[i]
                done = False
    output = []
    output_look_good = []
    number_loci = 0
    for index in output_indices:
        output.append(measurements.keys()[index])
        if len(measurements.keys()[index]) > number_loci:
            number_loci = len(measurements.keys()[index])
    for index in output_indices:
        output_look_good.append(genotype_look_good(measurements.keys()[index], number_loci))
    output_detailed = []
    for genotype in output:
        fitness = measurements[genotype][1:]
        output_detailed.append([genotype, np.mean(fitness)])
    if not details:
        return output
    else:
        return output_detailed
Exemplo n.º 14
0
def R4_IEEE2VAX(fpValue, varName):
    # type: (float, str) -> bytes
    """
    Convert floating point value to VAR REAL*4 string
    """
    try:
        m, e = math.frexp(float(fpValue))
        if m == 0.0:
            intValue = 0
        else:
            sign = m < 0
            exp = e + 128
            mant = int((0x1000000 * (abs(m) - 0.5)) + 0.5)
            while mant >= 0x800000:
                exp += 1
                mant = (mant>> 1) - 0x400000
            if exp < 1:
                intValue = 0
            elif exp > 0xff:
                raise Exception("Exponent too large to store as VAX F float for %s."
                                % varName)
            else:
                intValue = ((sign << 15)
                            | (exp << 7)
                            | ((mant & 0x007f0000) >> 16)
                            | ((mant & 0x0000ffff) << 16))
        return int_to_bytes(intValue)
    except:
        print("VAX float F conversion error for %s value: %s"
              % (varName, fpValue))
        return b"\0\0\0\0"
Exemplo n.º 15
0
    def float_to_decimal(f):
        "Convert a floating point number to a Decimal with no loss of information"
        # Transform (exactly) a float to a mantissa (0.5 <= abs(m) < 1.0) and an
        # exponent.  Double the mantissa until it is an integer.  Use the integer
        # mantissa and exponent to compute an equivalent Decimal.  If this cannot
        # be done exactly, then retry with more precision.

        try:
            mantissa, exponent = math.frexp(f)
        except OverflowError:
            return decimal.Inf

        while mantissa != int(mantissa):
            mantissa *= 2.0
            exponent -= 1
        mantissa = int(mantissa)

        oldcontext = decimal.getcontext()
        decimal.setcontext(decimal.Context(traps=[decimal.Inexact]))
        try:
            while True:
                try:
                    return mantissa * decimal.Decimal(2) ** exponent
                except decimal.Inexact:
                    decimal.getcontext().prec += 1
        finally:
            decimal.setcontext(oldcontext)
Exemplo n.º 16
0
 def __call__(self, x):
     if x == 0:
         return 0, self.mink
     import math
     m, e = math.frexp(x)
     k = max((e - self.bits, self.mink))
     return int(m * 2 ** (e - k)), k
Exemplo n.º 17
0
def encode_double(value):
    assert isinstance(value, float)
    abs_val = _math.fabs(value)
    # Work around repr()'s propensity to use exponential format
    # for doubles with really large or really small absolute values.
    # This extra work is because XML-RPC explicitly DOES NOT support
    # exponential format, just decimal digits separated by a single
    # period.
    if value and (abs_val < 0.0001):
        # Scary magic for small numbers, split the float into it's
        # mantissa and exponent components and use the exponent to
        # guess reasonable format.
        m, e = _math.frexp(abs_val)
        decimal_places = int(e/-3) + 17 # Derived at by pure, old-fashon,
                                        # trail and error.
        if decimal_places > 109:
            # "%.110f" causes an OverflowError.
            min_value = "0." + "0"*108 + "1"
            if abs_val < eval(min_value):
                value = min_value
            else:
                value = "%1.109f" % value
                value = value.rstrip('0')
        else:
            value = "%1.*f" % (decimal_places, value)
            value = value.rstrip('0')
    elif value and (abs_val > 99999999999999984.0):
        value = "%.1f" % value
    else:
        value = repr(value)
    return "<value><double>" + value + "</double></value>\n"
Exemplo n.º 18
0
def _hash_float(space, v):
    if not isfinite(v):
        if isinf(v):
            return HASH_INF if v > 0 else -HASH_INF
        return HASH_NAN

    m, e = math.frexp(v)

    sign = 1
    if m < 0:
        sign = -1
        m = -m

    # process 28 bits at a time;  this should work well both for binary
    # and hexadecimal floating point.
    x = r_uint(0)
    while m:
        x = ((x << 28) & HASH_MODULUS) | x >> (HASH_BITS - 28)
        m *= 268435456.0  # 2**28
        e -= 28
        y = r_uint(m)  # pull out integer part
        m -= y
        x += y
        if x >= HASH_MODULUS:
            x -= HASH_MODULUS

    # adjust for the exponent;  first reduce it modulo HASH_BITS
    e = e % HASH_BITS if e >= 0 else HASH_BITS - 1 - ((-1 - e) % HASH_BITS)
    x = ((x << e) & HASH_MODULUS) | x >> (HASH_BITS - e)

    x = intmask(intmask(x) * sign)
    return -2 if x == -1 else x
Exemplo n.º 19
0
def float2decimal(fval):
    """ Convert a floating point number to a Decimal with no loss of
        information
    """
    # Transform (exactly) a float to a mantissa (0.5 <= abs(m) < 1.0) and an
    # exponent.  Double the mantissa until it is an integer.  Use the integer
    # mantissa and exponent to compute an equivalent Decimal.  If this cannot
    # be done exactly, then retry with more precision.
    #
    # This routine is from
    # http://docs.python.org/release/2.5.2/lib/decimal-faq.html

    mantissa, exponent = math.frexp(fval)
    try:
        while mantissa != int(mantissa):
            mantissa *= 2.0
            exponent -= 1
        mantissa = int(mantissa)
    except (OverflowError, ValueError):
        return "---"

    oldcontext = decimal.getcontext()
    decimal.setcontext(decimal.Context(traps=[decimal.Inexact]))
    try:
        while True:
            try:
                return mantissa * decimal.Decimal(2) ** exponent
            except decimal.Inexact:
                decimal.getcontext().prec += 1
    finally:
        decimal.setcontext(oldcontext)
Exemplo n.º 20
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def naturallog(x):
    mantissa , exponent = math.frexp(x)
    ln2 = 0.693147180559945309417
    answer = 0
    for i in range (1,40):
        answer += -(-1)**i * ((mantissa - 1)**i/i)
    return(answer + exponent * ln2)
Exemplo n.º 21
0
def PyNextAfter(x, y):
    """returns the next float after x in the direction of y if possible, else returns x"""
    # if x or y is Nan, we don't do much
    if IsNaN(x) or IsNaN(y):
        return x

    # we can't progress if x == y
    if x == y:
        return x

    # similarly if x is infinity
    if x >= infinity or x <= -infinity:
        return x

    # return small numbers for x very close to 0.0
    if -minFloat < x < minFloat:
        if y > x:
            return x + smallEpsilon
        else:
            return x - smallEpsilon  # we know x != y

    # it looks like we have a normalized number
    # break x down into a mantissa and exponent
    m, e = math.frexp(x)

    # all the special cases have been handled
    if y > x:
        m += epsilon
    else:
        m -= epsilon

    return math.ldexp(m, e)
Exemplo n.º 22
0
def _write_float(f, x):
	import math
	if x < 0:
		sign = 0x8000
		x = x * -1
	else:
		sign = 0
	if x == 0:
		expon = 0
		himant = 0
		lomant = 0
	else:
		fmant, expon = math.frexp(x)
		if expon > 16384 or fmant >= 1:		# Infinity or NaN
			expon = sign|0x7FFF
			himant = 0
			lomant = 0
		else:					# Finite
			expon = expon + 16382
			if expon < 0:			# denormalized
				fmant = math.ldexp(fmant, expon)
				expon = 0
			expon = expon | sign
			fmant = math.ldexp(fmant, 32)
			fsmant = math.floor(fmant)
			himant = long(fsmant)
			fmant = math.ldexp(fmant - fsmant, 32)
			fsmant = math.floor(fmant)
			lomant = long(fsmant)
	_write_short(f, expon)
	_write_long(f, himant)
	_write_long(f, lomant)
Exemplo n.º 23
0
 def descr_hex(self, space):
     TOHEX_NBITS = rfloat.DBL_MANT_DIG + 3 - (rfloat.DBL_MANT_DIG + 2) % 4
     value = self.floatval
     if not isfinite(value):
         return self.descr_str(space)
     if value == 0.0:
         if copysign(1., value) == -1.:
             return space.wrap("-0x0.0p+0")
         else:
             return space.wrap("0x0.0p+0")
     mant, exp = math.frexp(value)
     shift = 1 - max(rfloat.DBL_MIN_EXP - exp, 0)
     mant = math.ldexp(mant, shift)
     mant = abs(mant)
     exp -= shift
     result = ['\0'] * ((TOHEX_NBITS - 1) // 4 + 2)
     result[0] = _char_from_hex(int(mant))
     mant -= int(mant)
     result[1] = "."
     for i in range((TOHEX_NBITS - 1) // 4):
         mant *= 16.0
         result[i + 2] = _char_from_hex(int(mant))
         mant -= int(mant)
     if exp < 0:
         sign = "-"
     else:
         sign = "+"
     exp = abs(exp)
     s = ''.join(result)
     if value < 0.0:
         return space.wrap("-0x%sp%s%d" % (s, sign, exp))
     else:
         return space.wrap("0x%sp%s%d" % (s, sign, exp))
Exemplo n.º 24
0
    def as_integer_ratio(self, a, **args):
        """Convert real number to a (numer, denom) pair. """
        v, n = math.frexp(a)  # XXX: hack, will work only for floats

        for i in xrange(300):
            if v != math.floor(v):
                v, n = 2*v, n - 1
            else:
                break

        numer, denom = int(v), 1

        m = 1 << abs(n)

        if n > 0:
            numer *= m
        else:
            denom = m

        n, d = self.limit_denom(numer, denom, **args)

        if a and not n:
            return numer, denom
        else:
            return n, d
Exemplo n.º 25
0
	def set_ref(self, refval):
		x = self.teach()
		m,e = math.frexp(refval / 5e-9)
		if m < 0:
			s = 0x80
			m = -m
		else:
			s = 0
		m = math.ldexp(m, -1)
		for i in range(14,20):
			m = math.ldexp(m, 8)
			h = int(m)
			m -= h
			x[i] = s | h
			s = 0
		
		e -= 31
		if e < 0:
			e += 256
		x[20] = e

		y=bytearray("LN")
		for i in x:
			if i == 10 or i == 27 or i == 13 or i == 43:
				y.append(27)
			y.append(i)
		d.wr(y)
Exemplo n.º 26
0
 def _bus_message_received_cb(self, bus, message):
     """
     @param bus: the message bus sending the message
     @param message: the message received
     """
     if message.get_structure().get_name() == 'level':
         s = message.get_structure()
         peak = list(s['peak'])
         decay = list(s['decay'])
         rms = list(s['rms'])
         for l in peak, decay, rms:
             for index, v in enumerate(l):
                 try:
                     v = frexp(v)
                 except (SystemError, OverflowError, ValueError):
                     # It was an invalid value (e.g. -Inf), so clamp to
                     # something appropriate
                     l[index] = -100.0
         if not self.uiState:
             self.warning("effect %s doesn't have a uiState" %
                          self.name)
         else:
             for k, v in ('peak', peak), ('decay', decay), ('rms', rms):
                 self.uiState.set('volume-%s' % k, v)
             if not self.firstVolumeValueReceived:
                 self.uiState.set('volume-volume', self.effect_getVolume())
                 self.firstVolumeValueReceived = True
Exemplo n.º 27
0
        def msum(iterable):
            """Full precision summation.  Compute sum(iterable) without any
            intermediate accumulation of error.  Based on the 'lsum' function
            at http://code.activestate.com/recipes/393090/

            """
            tmant, texp = 0, 0
            for x in iterable:
                mant, exp = math.frexp(x)
                mant, exp = int(math.ldexp(mant, mant_dig)), exp - mant_dig
                if texp > exp:
                    tmant <<= texp-exp
                    texp = exp
                else:
                    mant <<= exp-texp
                tmant += mant
            # Round tmant * 2**texp to a float.  The original recipe
            # used float(str(tmant)) * 2.0**texp for this, but that's
            # a little unsafe because str -> float conversion can't be
            # relied upon to do correct rounding on all platforms.
            tail = max(len(bin(abs(tmant)))-2 - mant_dig, etiny - texp)
            if tail > 0:
                h = 1 << (tail-1)
                tmant = tmant // (2*h) + bool(tmant & h and tmant & 3*h-1)
                texp += tail
            return math.ldexp(tmant, texp)
Exemplo n.º 28
0
def _write_float(f, x):
    import math
    if x < 0:
        sign = 32768
        x = x * -1
    else:
        sign = 0
    if x == 0:
        expon = 0
        himant = 0
        lomant = 0
    else:
        fmant, expon = math.frexp(x)
        if expon > 16384 or fmant >= 1 or fmant != fmant:
            expon = sign | 32767
            himant = 0
            lomant = 0
        else:
            expon = expon + 16382
            if expon < 0:
                fmant = math.ldexp(fmant, expon)
                expon = 0
            expon = expon | sign
            fmant = math.ldexp(fmant, 32)
            fsmant = math.floor(fmant)
            himant = long(fsmant)
            fmant = math.ldexp(fmant - fsmant, 32)
            fsmant = math.floor(fmant)
            lomant = long(fsmant)
    _write_ushort(f, expon)
    _write_ulong(f, himant)
    _write_ulong(f, lomant)
Exemplo n.º 29
0
 def get01(self, x):
     m, e = math.frexp(self._base - x)
     if m >= 0 and e <= _E_MAX:
         v = (e + m) / (2. * _E_MAX)
         return 1 - v
     else:
         return 1 if m < 0 else 0
Exemplo n.º 30
0
 def get01(self, x):
     m, e = math.frexp(x - self._base)
     if m >= 0 and e <= _E_MAX:
         v = (e + m) / (2. * _E_MAX)
         return v
     else:
         return 0 if m < 0 else 1
Exemplo n.º 31
0
print(math.factorial(6))
print(math.factorial(12))

# Round a number downward to its nearest integer
print(math.floor(1.4))
print(math.floor(5.3))
print(math.floor(-5.3))
print(math.floor(22.6))

# Return the remainder after modulo operation
print(math.fmod(67, 7))
print(math.fmod(17, 4))
print(math.fmod(16, 4))

#Return mantissa and exponent of a given number
print(math.frexp(4))
print(math.frexp(7.9))

# Print the sum of all items
print(math.fsum((1, 2, 3, 4, 5)))

#find the highest number that can divide two numbers
print(math.gcd(26, 12))
print(math.gcd(12, 6))
print(math.gcd(10, 0))
print(math.gcd(0, 34))
print(math.gcd(0, 0))

#compare the closeness of two values
print(math.isclose(1.233, 1.4566))
print(math.isclose(1.233, 1.233))
Exemplo n.º 32
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def t_math(n1):
    nf = math.ceil(n1)
    ng = math.floor(n1)
    nh = math.frexp(n1)

    print 'ceil:%s,floor:%s,frexp:%s' % (nf, ng, nh)
Exemplo n.º 33
0
    def __floor__(self):
        return 'floor'

assert math.trunc(A()) == 'trunc'
assert math.ceil(A()) == 'ceil'
assert math.floor(A()) == 'floor'

with assertRaises(TypeError):
    math.trunc(object())
with assertRaises(TypeError):
    math.ceil(object())
with assertRaises(TypeError):
    math.floor(object())

assert str(math.frexp(0.0)) == str((+0.0, 0))
assert str(math.frexp(-0.0)) == str((-0.0, 0))
assert math.frexp(1) == (0.5, 1)
assert math.frexp(1.5) == (0.75, 1)

assert math.frexp(float('inf')) == (float('inf'), 0)
assert str(math.frexp(float('nan'))) == str((float('nan'), 0))
assert_raises(TypeError, lambda: math.frexp(None))

assert math.gcd(0, 0) == 0
assert math.gcd(1, 0) == 1
assert math.gcd(0, 1) == 1
assert math.gcd(1, 1) == 1
assert math.gcd(-1, 1) == 1
assert math.gcd(1, -1) == 1
assert math.gcd(-1, -1) == 1
Exemplo n.º 34
0
Arquivo: fh.py Projeto: sajjadgol/DSA
def floor_log(x):
    return math.frexp(x)[1] - 1
Exemplo n.º 35
0
 def quantize_scale(scale):
     significand, shift = math.frexp(scale)
     significand_q31 = round(significand * (1 << 31))
     return significand_q31, shift
Exemplo n.º 36
0
def frexp(x):
    return math.frexp(x)
Exemplo n.º 37
0
def neon_math_frexp(self):
    x = self.stack.pop().value
    (m, e) = math.frexp(float(x))
    self.stack.append(Value(decimal.Decimal(e)))
    self.stack.append(Value(decimal.Decimal(m)))
Exemplo n.º 38
0
import math


print(dir(math))
print(math.ceil(-1))
print(math.ceil(1.024))

print(math.copysign(1, -1))
print(math.fabs(-1))
print(math.factorial(5))

print(math.floor(-1.024))
print(math.floor(1.024))
print(math.fmod(1, 2))

print(math.frexp(1024))
print(math.fsum([1, 2, 3, 4, 5, 6, 7, 8]))
print(math.gcd(3, 9))

print(math.exp(3))
print(math.expm1(3))

print(math.log(10, 24))
print(math.log1p(1024))

print(math.log2(1024))
print(math.log(10))
print(math.log10(100))
print(math.pow(3, 3))
print(math.sqrt(81))
print('------------------------')
Exemplo n.º 39
0
 def fn(x):
     res = frexp(x)
     return res[0] + float(res[1])
Exemplo n.º 40
0
assertEqual(math.fmod(-3.0, INF), -3.0)
assertEqual(math.fmod(3.0, NINF), 3.0)
assertEqual(math.fmod(-3.0, NINF), -3.0)
assertEqual(math.fmod(0.0, 3.0), 0.0)
assertEqual(math.fmod(0.0, NINF), 0.0)

doc="Frexp"
assertRaises(TypeError, math.frexp)

def testfrexp(name, result, expected):
    (mant, exp), (emant, eexp) = result, expected
    if abs(mant-emant) > eps or exp != eexp:
        fail('%s returned %r, expected %r'%\
                  (name, result, expected))

testfrexp('frexp(-1)', math.frexp(-1), (-0.5, 1))
testfrexp('frexp(0)', math.frexp(0), (0, 0))
testfrexp('frexp(1)', math.frexp(1), (0.5, 1))
testfrexp('frexp(2)', math.frexp(2), (0.5, 2))

assertEqual(math.frexp(INF)[0], INF)
assertEqual(math.frexp(NINF)[0], NINF)
assertTrue(math.isnan(math.frexp(NAN)[0]))

doc="Fsum"
# math.fsum relies on exact rounding for correct operation.
# There's a known problem with IA32 floating-point that causes
# inexact rounding in some situations, and will cause the
# math.fsum tests below to fail; see issue #2937.  On non IEEE
# 754 platforms, and on IEEE 754 platforms that exhibit the
# problem described in issue #2937, we simply skip the whole
Exemplo n.º 41
0
 def frexp(self):
     import math
     return AdvTuple(math.frexp(self))
Exemplo n.º 42
0
    def test_frexp(self):
        self.assertRaises(TypeError, math.frexp)

        def testfrexp(name, result, expected):
            (mant, exp), (emant, eexp) = result, expected
            if abs(mant - emant) > eps or exp != eexp:
                self.fail('%s returned %r, expected %r'%\
                          (name, result, expected))

        testfrexp('frexp(-1)', math.frexp(-1), (-0.5, 1))
        testfrexp('frexp(0)', math.frexp(0), (0, 0))
        testfrexp('frexp(1)', math.frexp(1), (0.5, 1))
        testfrexp('frexp(2)', math.frexp(2), (0.5, 2))

        self.assertEqual(math.frexp(INF)[0], INF)
        self.assertEqual(math.frexp(NINF)[0], NINF)
        self.assertTrue(math.isnan(math.frexp(NAN)[0]))

        testfrexp('frexp(True)', math.frexp(True), (0.5, 1))
        testfrexp('frexp(False)', math.frexp(False), (0.0, 0))
        testfrexp('frexp(6227020800)', math.frexp(6227020800),
                  (0.7249206304550171, 33))
        testfrexp('frexp(2432902008176640000999)',
                  math.frexp(2432902008176640000999), (0.5151870395916913, 72))
        self.assertRaises(TypeError, math.frexp, 'hello')

        class X(int):
            def getX():
                return 'Ahoj'

        class Y(float):
            def getY():
                return 'Ahoj'

        testfrexp('frexp(X(10))', math.frexp(X(10)), (0.625, 4))
        testfrexp('frexp(Y(11.11))', math.frexp(Y(11.11)), (0.694375, 4))
Exemplo n.º 43
0
print 'fmod'
testit('fmod(10,1)', math.fmod(10,1), 0)
testit('fmod(10,0.5)', math.fmod(10,0.5), 0)
testit('fmod(10,1.5)', math.fmod(10,1.5), 1)
testit('fmod(-10,1)', math.fmod(-10,1), 0)
testit('fmod(-10,0.5)', math.fmod(-10,0.5), 0)
testit('fmod(-10,1.5)', math.fmod(-10,1.5), -1)

print 'frexp'
def testfrexp(name, (mant, exp), (emant, eexp)):
    if abs(mant-emant) > eps or exp != eexp:
        raise TestFailed, '%s returned %s, expected %s'%\
              (name, `mant, exp`, `emant,eexp`)

testfrexp('frexp(-1)', math.frexp(-1), (-0.5, 1))
testfrexp('frexp(0)', math.frexp(0), (0, 0))
testfrexp('frexp(1)', math.frexp(1), (0.5, 1))
testfrexp('frexp(2)', math.frexp(2), (0.5, 2))

print 'hypot'
testit('hypot(0,0)', math.hypot(0,0), 0)
testit('hypot(3,4)', math.hypot(3,4), 5)

print 'ldexp'
testit('ldexp(0,1)', math.ldexp(0,1), 0)
testit('ldexp(1,1)', math.ldexp(1,1), 2)
testit('ldexp(1,-1)', math.ldexp(1,-1), 0.5)
testit('ldexp(-1,1)', math.ldexp(-1,1), -2)

print 'log'
Exemplo n.º 44
0
# constant to be used when iterating with range() over all considered quantum effects
# (range() is exclusive with respect to the last element)
S_LAST_INDEX = 1

# construction of aCLIMAX constant which is used to evaluate mean square displacement (u)
with warnings.catch_warnings(record=True) as warning_list:
    warnings.simplefilter("always")
    H_BAR = constants.codata.value(
        "Planck constant over 2 pi"
    )  # H_BAR =  1.0545718e-34 [J s] = [kg m^2 / s ]
    if len(warning_list) >= 1 and isinstance(warning_list[0].message,
                                             ConstantWarning):
        H_BAR = constants.hbar  # H_BAR =  1.0545718e-34 [J s] = [kg m^2 / s ]

H_BAR_DECOMPOSITION = math.frexp(H_BAR)

M2_TO_ANGSTROM2 = 1.0 / constants.angstrom**2  # m^2 = 10^20 A^2
M2_TO_ANGSTROM2_DECOMPOSITION = math.frexp(M2_TO_ANGSTROM2)

KG2AMU = constants.codata.value(
    "kilogram-atomic mass unit relationship")  # kg = 6.022140857e+26 amu
KG2AMU_DECOMPOSITION = math.frexp(KG2AMU)

# here we divide by 100 because we need relation between hertz and inverse cm
HZ2INV_CM = constants.codata.value(
    "hertz-inverse meter relationship"
) / 100  # Hz [s^1] = 3.33564095198152e-11 [cm^-1]
HZ2INV_CM_DECOMPOSITION = math.frexp(HZ2INV_CM)

# Conversion factor from VASP internal units
import math

pow(3, 2)
for i in range(1, 11):
    print(pow(i, 2))  # for print the square of first 10 numbers
    print(pow(i, 3))  # for print the cube of first 10 numbers
    print(pow(i, 0.5))  # for print the square root of first 10 numbers

lst = [11, 32, 34, 54, 67, 87, 24, 55, 36, 87]
max(lst)  # returns the maximum numbers
min(lst)  # returns the minimum numbers
math.ceil(5)  # ceil and floor numbers
math.copysign(5, -1)  # copy the sign of y
math.factorial(5)  # returns the factorial of the numbers
math.fmod(40, 6)  # returns the remainder
math.frexp(5)  # returns the exponent of x as the pair of (m,e)
math.sum(lst)  # returns the sum of the values present
math.exp(5)  # returns the exponent of (e,5)
math.expm1(6)  # returns the value of e**x-1
math.sqrt(5)  # returns the square root of x
math.gcd(46, 84)  # returns the greatest common divisor
math.lcm(25, 20)  # returns the least common multiple
math.nextafter(
    34, 36
)  # returns the next number in floting point either towards zero/opposite
math.prod(lst)  # returns the product of all availale iterables
math.remainder(6, 5)  # returns the reaminder
Exemplo n.º 46
0
assert d == {'a': 1, 'b': 2.1}
assert type(d['a']) == int
assert type(d['b']) == float

# issue 203
def f(z):
  z += 1
  return z

x = 1.0

assert x != f(x)

# issue 204
import math
m, e = math.frexp(abs(123.456))
assert m == 0.9645
assert m * (1 << 24) == 16181624.832

# issue 207

for x in range(0x7ffffff0, 0x8000000f):
    assert x & x == x, "%s & %s == %s" % (hex(x), hex(x), hex(x & x))
    assert x | x == x, "%s | %s == %s" % (hex(x), hex(x), hex(x | x))

for x in range(0x17ffffff0, 0x17fffffff):
    assert x & x == x, "%s & %s == %s" % (hex(x), hex(x), hex(x & x))
    assert x | x == x, "%s | %s == %s" % (hex(x), hex(x), hex(x | x))

# issue 208
a=5
Exemplo n.º 47
0
 def test_frexp(self, space):
     w_res = space.execute("return Math.frexp(1234)")
     assert self.unwrap(space, w_res) == [math.frexp(1234)[0], 11]
Exemplo n.º 48
0
def round_double(value, ndigits, half_even=False):
    """Round a float half away from zero.

    Specify half_even=True to round half even instead.
    The argument 'value' must be a finite number.  This
    function may return an infinite number in case of
    overflow (only if ndigits is a very negative integer).
    """
    if ndigits == 0:
        # fast path for this common case
        if half_even:
            return round_half_even(value)
        else:
            return round_away(value)

    if value == 0.0:
        return 0.0

    # The basic idea is very simple: convert and round the double to
    # a decimal string using _Py_dg_dtoa, then convert that decimal
    # string back to a double with _Py_dg_strtod.  There's one minor
    # difficulty: Python 2.x expects round to do
    # round-half-away-from-zero, while _Py_dg_dtoa does
    # round-half-to-even.  So we need some way to detect and correct
    # the halfway cases.

    # a halfway value has the form k * 0.5 * 10**-ndigits for some
    # odd integer k.  Or in other words, a rational number x is
    # exactly halfway between two multiples of 10**-ndigits if its
    # 2-valuation is exactly -ndigits-1 and its 5-valuation is at
    # least -ndigits.  For ndigits >= 0 the latter condition is
    # automatically satisfied for a binary float x, since any such
    # float has nonnegative 5-valuation.  For 0 > ndigits >= -22, x
    # needs to be an integral multiple of 5**-ndigits; we can check
    # this using fmod.  For -22 > ndigits, there are no halfway
    # cases: 5**23 takes 54 bits to represent exactly, so any odd
    # multiple of 0.5 * 10**n for n >= 23 takes at least 54 bits of
    # precision to represent exactly.

    sign = copysign(1.0, value)
    value = abs(value)

    # find 2-valuation value
    m, expo = math.frexp(value)
    while m != math.floor(m):
        m *= 2.0
        expo -= 1

    # determine whether this is a halfway case.
    halfway_case = 0
    if not half_even and expo == -ndigits - 1:
        if ndigits >= 0:
            halfway_case = 1
        elif ndigits >= -22:
            # 22 is the largest k such that 5**k is exactly
            # representable as a double
            five_pow = 1.0
            for i in range(-ndigits):
                five_pow *= 5.0
            if math.fmod(value, five_pow) == 0.0:
                halfway_case = 1

    # round to a decimal string; use an extra place for halfway case
    strvalue = formatd(value, 'f', ndigits + halfway_case)

    if not half_even and halfway_case:
        buf = [c for c in strvalue]
        if ndigits >= 0:
            endpos = len(buf) - 1
        else:
            endpos = len(buf) + ndigits
        # Sanity checks: there should be exactly ndigits+1 places
        # following the decimal point, and the last digit in the
        # buffer should be a '5'
        if not objectmodel.we_are_translated():
            assert buf[endpos] == '5'
            if '.' in buf:
                assert endpos == len(buf) - 1
                assert buf.index('.') == len(buf) - ndigits - 2

        # increment and shift right at the same time
        i = endpos - 1
        carry = 1
        while i >= 0:
            digit = ord(buf[i])
            if digit == ord('.'):
                buf[i + 1] = chr(digit)
                i -= 1
                digit = ord(buf[i])

            carry += digit - ord('0')
            buf[i + 1] = chr(carry % 10 + ord('0'))
            carry /= 10
            i -= 1
        buf[0] = chr(carry + ord('0'))
        if ndigits < 0:
            buf.append('0')

        strvalue = ''.join(buf)

    return sign * rstring_to_float(strvalue)
Exemplo n.º 49
0
def compare_floats(v, val):
    from math import frexp
    vm, ve = frexp(val)
    scale = 2.0**(-ve)
    delta = abs(v * scale - val * scale)
    return delta < 1.e-14
Exemplo n.º 50
0
import math

# Sign Manipulation
print(math.copysign(
    -2, -1))  # Copy the sign of the second arg to the first and return it.
print(math.fabs(-2))  # Return the absolute value

# Sequences
print(math.factorial(5))  # Return the value of !5

# Working with Floats
print(math.frexp(5))
print(math.ldexp(.625, 3))
print(sum([.1] * 10))  # Precision limited to 16 decimal points.
print(math.fsum([.1] * 10))  # Accurately sum floats to infinite precision

# Modulus
print(math.fmod(-1e-100, 1e100))  # Accurate modulus for working with floats
print(math.modf(5.123456))
print(math.remainder(37.123, 7))
print(37.123 % 7)

# Factoring
print(math.gcd(35, 3500), math.gcd(42, 2996))

# Testing for numeric attributes
print(math.isfinite(math.inf))
print(math.isfinite(0.0))
print(math.isinf(math.inf))
print(math.isnan(float('nan')))
print(
Exemplo n.º 51
0
def quantize_scale(scale):
    multiplier, shift = math.frexp(scale)
    multiplier_q31 = round(multiplier * (1 << 31))
    return multiplier_q31, shift
    TEST_VALUES.append( rand )
for t in sorted(TEST_VALUES):
    print fmt.format(t, int(t), math.trunc(t), math.floor(t), math.ceil(t) )
print

## 5.4.4 Alternate Representations
# modf separates the number into a (portion, whole)
for i in xrange(6):
    print '{}/2 = {}'.format(i, math.modf(i/2.0))
print

# frexp(x) returns (m, e), where x = m + 2**e
print ' '.join(['{:^7}'] * 3).format('x','m','e')
print ' '.join(['{:-^7}'] * 3).format('','','')
for x in [0.1, 0.5, 4.0]:
    m,e = math.frexp(x)
    print '{:7.2f} {:7.2f} {:7d}'.format( x, m, e )
    
# ldexp(m,e) returns x, where x = m + 2**e
print ' '.join(['{:^7}'] * 3).format('m','e','x')
print ' '.join(['{:-^7}'] * 3).format('','','')
for m,e in [ (0.8, -3), (0.5, 0), (0.5, 3) ]:
    x = math.ldexp(m, e)
    print '{:7.2f} {:7d} {:7.2f}'.format( m, e, x )
print

## 5.4.5 Positive and Negative Signs
print math.fabs(-1.1)
print math.fabs(-0.0)
print math.fabs( 0.0)
print math.fabs( 1.1)
Exemplo n.º 53
0
def frexp(x):
    if isinstance(x, LineValue): lx = x.get_value()
    else: lx = x
    if lx == NAN: return LineValue(NAN)
    return LineValue(math.frexp(lx))
Exemplo n.º 54
0
def solve_control(density,
                  velocity,
                  target,
                  remaining_time,
                  level_control=False,
                  velocity_generator=multi_scale_control_cnn_16_2):
    rank = spatial_rank(density)
    size = int(max(density.shape[1:]))

    # Create density grids
    density_grids = [to_dipole_format(density)]
    target_grids = [to_dipole_format(target)]
    velocity_grids = [velocity]
    for i in range(pymath.frexp(float(size))[1] - 1):  # downsample until 1x1
        density_grids.insert(0, moment_downsample2x(density_grids[0],
                                                    sum=True))
        target_grids.insert(0, moment_downsample2x(target_grids[0], sum=True))
        velocity_grids.insert(0, downsample2x(velocity_grids[0]))

    added_velocity = None

    level_scalings = []
    velocities_by_level = []

    for i in range(len(density_grids)):
        density_grid = density_grids[i]
        target_grid = target_grids[i]
        velocity_grid = velocity_grids[i]

        if added_velocity is None:
            combined_velocity = velocity_grid
        else:
            added_velocity = upsample2x(added_velocity)[:, 2:-2, 2:-2, :]
            combined_velocity = velocity_grid + added_velocity

        # Add border pixel for smooth upsampling at the edges
        padded_density = tf.pad(density_grid,
                                [[0, 0]] + [[1, 1]] * rank + [[0, 0]])
        padded_target = tf.pad(target_grid,
                               [[0, 0]] + [[1, 1]] * rank + [[0, 0]])
        padded_velocity = tf.pad(combined_velocity,
                                 [[0, 0]] + [[1, 1]] * rank + [[0, 0]])
        if added_velocity is not None:
            added_velocity = tf.pad(added_velocity,
                                    [[0, 0]] + [[1, 1]] * rank + [[0, 0]],
                                    mode="SYMMETRIC")

        added_velocity_lvl = velocity_generator(padded_density,
                                                padded_velocity, padded_target,
                                                remaining_time, i)
        velocities_by_level.append(added_velocity_lvl)

        level_scaling = create_level_scaling(level_control, i)
        level_scalings.append(level_scaling)

        if added_velocity is None:
            added_velocity = added_velocity_lvl * level_scaling
        else:
            added_velocity += added_velocity_lvl * level_scaling

    return added_velocity[:, 1:-1,
                          1:-1, :], (level_scalings, velocities_by_level)
#Урок номер 6 по модулю Math

import math

print("Длина строки", len("123"))
print("Округление", round(8.6))
print("Число ПИ", math.pi)
print("Число эллера", math.e)
print("Возведение в степень", math.pow(2, 3))  # 2**3
print("Остаток от деления", math.fmod(7, 3))  # 7%3
x = 5
print("Проверка на число", math.isfinite(x))
print("Проверка на бесконечность", math.isinf(x))
print("Мантисса и экспонента", math.frexp(123.456))
print("Квадратный корень", math.sqrt(9))
print("Модуль", math.fabs(-20))
print("Модуль числа 1, со знаком числа 2", math.copysign(-10, 5))
print("Отделяет целую часть и дробную", math.modf(123.456))
print("Округление в большую", math.ceil(4.1))
print("Округление в меньшую", math.floor(4.9))
print("Отбрасывание дробной части", math.trunc(8.9))
print("Отбрасывание дробной части", math.trunc(8.9))
print("Косинус угла", math.cos(math.radians(60)))
print("Синус угла", math.sin(math.radians(30)))
print("Тангенс угла", math.tan(math.radians(45)))
print("Гипотенуза", math.hypot(3, 4))
print("Логaрифм", math.log(8, 2))
print("Логaрифм десятичный", math.log10(100))

input()
Exemplo n.º 56
0
 def entry_point(argv):
     m, e = math.frexp(0)
     x, y = math.frexp(0)
     print m, x
     return 0
Exemplo n.º 57
0
class FixedPoint:

    # the exact value is self.n / 10**self.p;
    # self.n is a long; self.p is an int

    def __init__(self, value=0, precision=DEFAULT_PRECISION):
        self.n = self.p = 0
        self.set_precision(precision)
        p = self.p

        if isinstance(value, type("42.3e5")):
            n, exp = _string2exact(value)
            # exact value is n*10**exp = n*10**(exp+p)/10**p
            effective_exp = exp + p
            if effective_exp > 0:
                n = n * _tento(effective_exp)
            elif effective_exp < 0:
                n = _roundquotient(n, _tento(-effective_exp))
            self.n = n
            return

        if isinstance(value, type(42)) or isinstance(value, type(42L)):
            self.n = long(value) * _tento(p)
            return

        if isinstance(value, FixedPoint):
            temp = value.copy()
            temp.set_precision(p)
            self.n, self.p = temp.n, temp.p
            return

        if isinstance(value, type(42.0)):
            # XXX ignoring infinities and NaNs and overflows for now
            import math
            f, e = math.frexp(abs(value))
            assert f == 0 or 0.5 <= f < 1.0
            # |value| = f * 2**e exactly

            # Suck up CHUNK bits at a time; 28 is enough so that we suck
            # up all bits in 2 iterations for all known binary double-
            # precision formats, and small enough to fit in an int.
            CHUNK = 28
            top = 0L
            # invariant: |value| = (top + f) * 2**e exactly
            while f:
                f = math.ldexp(f, CHUNK)
                digit = int(f)
                assert digit >> CHUNK == 0
                top = (top << CHUNK) | digit
                f = f - digit
                assert 0.0 <= f < 1.0
                e = e - CHUNK

            # now |value| = top * 2**e exactly
            # want n such that n / 10**p = top * 2**e, or
            # n = top * 10**p * 2**e
            top = top * _tento(p)
            if e >= 0:
                n = top << e
            else:
                n = _roundquotient(top, 1L << -e)
            if value < 0:
                n = -n
            self.n = n
            return

        if isinstance(value, type(42 - 42j)):
            raise TypeError("can't convert complex to FixedPoint: " +
                            ` value `)

        # can we coerce to a float?
        yes = 1
        try:
            asfloat = float(value)
        except:
            yes = 0
        if yes:
            self.__init__(asfloat, p)
            return

        # similarly for long
        yes = 1
        try:
            aslong = long(value)
        except:
            yes = 0
        if yes:
            self.__init__(aslong, p)
            return

        raise TypeError("can't convert to FixedPoint: " + ` value `)
Exemplo n.º 58
0
# 25

# Return True if the values a and b are close to each other and False otherwise.
math.isclose(1.000000002, 1.000000001)
# True
math.isclose(1.000000003, 1.000000001)
# False

# base-2 logarithm of x
x = 2
# -> float
math.log(x, 2.0)  # slow
math.log2(x)
# 1.0
# -> int
math.frexp(x)[1] - 1  # fast
x.bit_length() - 1  # faster
# 1

# decimal: accurate decimal math, eg: for money
from decimal import Decimal
sum(0.1 for i in range(1000))
# 99.9999999999986
sum(Decimal('0.1') for i in range(1000))
# Decimal('100.0')
Decimal(0.1)  # be careful converting from floats!
# Decimal('0.1000000000000000055511151231257827021181583404541015625')


def digits(n: int) -> Generator[int, None, None]:
    # How to get the digits of an integer
Exemplo n.º 59
0
def compare_floats(v, val):
  vm, ve = math.frexp(val)
  scale = 2.0**(-ve)
  delta = abs(v*scale - val*scale)
  return delta < 1.e-14
Exemplo n.º 60
0
 def method_frexp(self, space, value):
     mant, exp = math.frexp(value)
     w_mant = space.newfloat(mant)
     w_exp = space.newint(exp)
     return space.newarray([w_mant, w_exp])