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Python math.ldexp函数代码示例

原作者: [db:作者] 来自: [db:来源] 收藏 邀请

本文整理汇总了Python中math.ldexp函数的典型用法代码示例。如果您正苦于以下问题:Python ldexp函数的具体用法?Python ldexp怎么用?Python ldexp使用的例子?那么恭喜您, 这里精选的函数代码示例或许可以为您提供帮助。



在下文中一共展示了ldexp函数的20个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于我们的系统推荐出更棒的Python代码示例。

示例1: get_heavy_correction

def get_heavy_correction(beta, heavytype):
    m = get_heavyq_mass(beta, heavytype)

    def prop(p):
        W = 1-np.cos(p)
        Weplus = W + 1./2 + np.sqrt(W + 1./4)
        Wemins = W + 1./2 - np.sqrt(W + 1./4)
        num = np.sin(p) * np.sin(p*t) + m*(1-Wemins) * np.cos(p*t)
        #num = 2*np.sin(p) * np.sin(p*t) #+ m*(1-Wemins) * np.cos(p*t)
        den = - (1-Weplus) + m**2*(1-Wemins)
        return num/den /(2*np.pi)

    Q = ((1+m**2)/(1-m**2))**2
    T  = (1-Q)/2 + np.sqrt(3*Q+Q**2)/2
    W0 = (1+Q)/2 - np.sqrt(3*Q+Q**2)/2
    m1 = np.log(T+np.sqrt(T**2-1))
    K = 2.0/((1-m**2)*(1.0+np.sqrt(Q/(1.0+4*W0))))

    Nt = 65
    it = np.arange(Nt)
    Ct = np.empty(Nt)
    R  = {}
    minDouble  = math.ldexp(1.0, -1022)
    smallEpsilon  = math.ldexp(1.0, -1074)
    epsilon  = math.ldexp(1.0, -53)
    for t in it:
        Ct[t], err = integrate.quad(prop,-np.pi,np.pi)
        if Ct[t] < err or (K*np.exp(-m1*t)) < err:
            R[t] = 1.
        else:
            R[t] = Ct[t] / (K*np.exp(-m1*t))

    return R
开发者ID:f4hy,项目名称:effectivemass,代码行数:33,代码来源:heavy_correction_dicts.py


示例2: _write_float

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)
开发者ID:asottile,项目名称:ancient-pythons,代码行数:32,代码来源:aifc.py


示例3: set_ref

	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)
开发者ID:PeterMortensen,项目名称:pylt,代码行数:27,代码来源:hp5370b.py


示例4: msum

        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)
开发者ID:Androtos,项目名称:toolchain_benchmark,代码行数:26,代码来源:test_math.py


示例5: sqrt

def sqrt(x):
    sqrt_special = [
        [inf-infj, 0-infj, 0-infj, infj, infj, inf+infj, nan+infj],
        [inf-infj, None, None, None, None, inf+infj, nan+nanj],
        [inf-infj, None, 0-0j, 0+0j, None, inf+infj, nan+nanj],
        [inf-infj, None, 0-0j, 0+0j, None, inf+infj, nan+nanj],
        [inf-infj, None, None, None, None, inf+infj, nan+nanj],
        [inf-infj, complex(float("inf"), -0.0), complex(float("inf"), -0.0), inf, inf, inf+infj, inf+nanj],
        [inf-infj, nan+nanj, nan+nanj, nan+nanj, nan+nanj, inf+infj, nan+nanj]
    ]

    z = _make_complex(x)

    if math.isinf(z.real) or math.isinf(z.imag):
        return sqrt_special[_special_type(z.real)][_special_type(z.imag)]

    abs_x, abs_y = abs(z.real), abs(z.imag)
    if abs_x < _DBL_MIN and abs_y < _DBL_MIN:
        if abs_x > 0 or abs_y > 0:
            abs_x = math.ldexp(abs_x, _CM_SCALE_UP)
            s = math.ldexp(math.sqrt(abs_x +
                                     math.hypot(abs_x,
                                                math.ldexp(abs_y,
                                                           _CM_SCALE_UP))),
                           _CM_SCALE_DOWN)
        else:
            return complex(0, z.imag)
    else:
        abs_x /= 8
        s = 2 * math.sqrt(abs_x + math.hypot(abs_x, abs_y/8))

    if z.real >= 0:
        return complex(s, math.copysign(abs_y/(2*s), z.imag))
    return complex(abs_y/(2*s), math.copysign(s, z.imag))
开发者ID:pombredanne,项目名称:ouroboros,代码行数:34,代码来源:cmath.py


示例6: _write_float

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)
开发者ID:webiumsk,项目名称:WOT-0.9.12,代码行数:32,代码来源:aifc.py


示例7: to_float

def to_float(s, strict=False):
    """
    Convert a raw mpf to a Python float. The result is exact if the
    bitcount of s is <= 53 and no underflow/overflow occurs.

    If the number is too large or too small to represent as a regular
    float, it will be converted to inf or 0.0. Setting strict=True
    forces an OverflowError to be raised instead.
    """
    sign, man, exp, bc = s
    if not man:
        if s == fzero: return 0.0
        if s == finf: return math_float_inf
        if s == fninf: return -math_float_inf
        return math_float_inf/math_float_inf
    if sign:
        man = -man
    try:
        if bc < 100:
            return math.ldexp(man, exp)
        # Try resizing the mantissa. Overflow may still happen here.
        n = bc - 53
        m = man >> n
        return math.ldexp(m, exp + n)
    except OverflowError:
        if strict:
            raise
        # Overflow to infinity
        if exp + bc > 0:
            if sign:
                return -math_float_inf
            else:
                return math_float_inf
        # Underflow to zero
        return 0.0
开发者ID:Tkizzy,项目名称:PythonistaAppTemplate,代码行数:35,代码来源:libmpf.py


示例8: ldexp

def ldexp(x, y):
    # 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.).

    # Another approach would be to add an additional argument to
    # uncertainties.wrap() so that some arguments are automatically
    # considered as constants.

    aff_func = to_affine_scalar(x)  # y must be an integer, for math.ldexp

    if aff_func.derivatives:
        factor = 2**y
        return AffineScalarFunc(
            math.ldexp(aff_func.nominal_value, y),
            # Chain rule:
            dict([(var, factor*deriv)
                  for (var, deriv) in aff_func.derivatives.iteritems()]))
    else:
        # This function was not called with an AffineScalarFunc
        # argument: there is no need to return numbers with uncertainties:

        # aff_func.nominal_value is not passed instead of x, because
        # we do not have to care about the type of the return value of
        # math.ldexp, this way (aff_func.nominal_value might be the
        # value of x coerced to a difference type [int->float, for
        # instance]):
        return math.ldexp(x, y)
开发者ID:cgd8d,项目名称:ComptonTelescope,代码行数:28,代码来源:umath.py


示例9: __init__

	def __init__(self, pj, lo):
		super(float70, self).__init__(pj, lo, lo + 7)
		x = pj.m.rd(self.lo)
		if x & 0x80:
			s = -1
			x ^= 0x80
		else:
			s = 1
		o = -7
		m = 0
		for i in range(6):
			m +=  math.ldexp(x, o)
			o -= 8
			x = pj.m.rd(self.lo + 1 + i)
		e =  pj.m.s8(self.lo + 6)
		self.lcmt = "m %g e %g" % (m, e)
		v = s * math.ldexp(m, e)
		self.val = v

		x = "%.9e" % v
		if x.find(".") == -1 and x.find("e") == -1:
			x += "."
		self.fmt = x
		self.typ = ".FLOAT"
		self.compact = False
		pj.set_label(lo, "c_" + x)
		print(self, self.fmt)
开发者ID:liveck,项目名称:PyReveng3,代码行数:27,代码来源:utils.py


示例10: test_705836

    def test_705836(self):
        # SF bug 705836.  "<f" and ">f" had a severe rounding bug, where a carry
        # from the low-order discarded bits could propagate into the exponent
        # field, causing the result to be wrong by a factor of 2.
        for base in range(1, 33):
            # smaller <- largest representable float less than base.
            delta = 0.5
            while base - delta / 2.0 != base:
                delta /= 2.0
            smaller = base - delta
            # Packing this rounds away a solid string of trailing 1 bits.
            packed = struct.pack("<f", smaller)
            unpacked = struct.unpack("<f", packed)[0]
            # This failed at base = 2, 4, and 32, with unpacked = 1, 2, and
            # 16, respectively.
            self.assertEqual(base, unpacked)
            bigpacked = struct.pack(">f", smaller)
            self.assertEqual(bigpacked, string_reverse(packed))
            unpacked = struct.unpack(">f", bigpacked)[0]
            self.assertEqual(base, unpacked)

        # Largest finite IEEE single.
        big = (1 << 24) - 1
        big = math.ldexp(big, 127 - 23)
        packed = struct.pack(">f", big)
        unpacked = struct.unpack(">f", packed)[0]
        self.assertEqual(big, unpacked)

        # The same, but tack on a 1 bit so it rounds up to infinity.
        big = (1 << 25) - 1
        big = math.ldexp(big, 127 - 24)
        self.assertRaises(OverflowError, struct.pack, ">f", big)
开发者ID:M31MOTH,项目名称:cpython,代码行数:32,代码来源:test_struct.py


示例11: float_unpack

def float_unpack(Q, size):
    """Convert a 16-bit, 32-bit, or 64-bit integer created
    by float_pack into a Python float."""
    if size == 8:
        MIN_EXP = -1021  # = sys.float_info.min_exp
        MAX_EXP = 1024  # = sys.float_info.max_exp
        MANT_DIG = 53  # = sys.float_info.mant_dig
        BITS = 64
    elif size == 4:
        MIN_EXP = -125  # C's FLT_MIN_EXP
        MAX_EXP = 128  # FLT_MAX_EXP
        MANT_DIG = 24  # FLT_MANT_DIG
        BITS = 32
    elif size == 2:
        MIN_EXP = -13
        MAX_EXP = 16
        MANT_DIG = 11
        BITS = 16
    else:
        raise ValueError("invalid size value")

    if not objectmodel.we_are_translated():
        # This tests generates wrong code when translated:
        # with gcc, shifting a 64bit int by 64 bits does
        # not change the value.
        if Q >> BITS:
            raise ValueError("input '%r' out of range '%r'" % (Q, Q >> BITS))

    # extract pieces with assumed 1.mant values
    one = r_ulonglong(1)
    sign = rarithmetic.intmask(Q >> BITS - 1)
    exp = rarithmetic.intmask((Q & ((one << BITS - 1) - (one << MANT_DIG - 1))) >> MANT_DIG - 1)
    mant = Q & ((one << MANT_DIG - 1) - 1)

    if exp == MAX_EXP - MIN_EXP + 2:
        # nan or infinity
        if mant == 0:
            result = rfloat.INFINITY
        else:
            # preserve at most 52 bits of mant value, but pad w/zeros
            exp = r_ulonglong(0x7FF) << 52
            sign = r_ulonglong(sign) << 63
            if MANT_DIG < 53:
                mant = r_ulonglong(mant) << (53 - MANT_DIG)
            if mant == 0:
                result = rfloat.NAN
            else:
                uint = exp | mant | sign
                result = longlong2float(cast(LONGLONG, uint))
            return result
    elif exp == 0:
        # subnormal or zero
        result = math.ldexp(mant, MIN_EXP - MANT_DIG)
    else:
        # normal: add implicit one value
        mant += one << MANT_DIG - 1
        result = math.ldexp(mant, exp + MIN_EXP - MANT_DIG - 1)
    return -result if sign else result
开发者ID:cimarieta,项目名称:usp,代码行数:58,代码来源:ieee.py


示例12: c_log

def c_log(x, y):
    # The usual formula for the real part is log(hypot(z.real, z.imag)).
    # There are four situations where this formula is potentially
    # problematic:
    #
    # (1) the absolute value of z is subnormal.  Then hypot is subnormal,
    # so has fewer than the usual number of bits of accuracy, hence may
    # have large relative error.  This then gives a large absolute error
    # in the log.  This can be solved by rescaling z by a suitable power
    # of 2.
    #
    # (2) the absolute value of z is greater than DBL_MAX (e.g. when both
    # z.real and z.imag are within a factor of 1/sqrt(2) of DBL_MAX)
    # Again, rescaling solves this.
    #
    # (3) the absolute value of z is close to 1.  In this case it's
    # difficult to achieve good accuracy, at least in part because a
    # change of 1ulp in the real or imaginary part of z can result in a
    # change of billions of ulps in the correctly rounded answer.
    #
    # (4) z = 0.  The simplest thing to do here is to call the
    # floating-point log with an argument of 0, and let its behaviour
    # (returning -infinity, signaling a floating-point exception, setting
    # errno, or whatever) determine that of c_log.  So the usual formula
    # is fine here.

    # XXX the following two lines seem unnecessary at least on Linux;
    # the tests pass fine without them
    if not isfinite(x) or not isfinite(y):
        return log_special_values[special_type(x)][special_type(y)]

    ax = fabs(x)
    ay = fabs(y)

    if ax > CM_LARGE_DOUBLE or ay > CM_LARGE_DOUBLE:
        real = math.log(math.hypot(ax/2., ay/2.)) + M_LN2
    elif ax < DBL_MIN and ay < DBL_MIN:
        if ax > 0. or ay > 0.:
            # catch cases where hypot(ax, ay) is subnormal
            real = math.log(math.hypot(math.ldexp(ax, DBL_MANT_DIG),
                                       math.ldexp(ay, DBL_MANT_DIG)))
            real -= DBL_MANT_DIG*M_LN2
        else:
            # log(+/-0. +/- 0i)
            raise ValueError("math domain error")
            #real = -INF
            #imag = atan2(y, x)
    else:
        h = math.hypot(ax, ay)
        if 0.71 <= h and h <= 1.73:
            am = max(ax, ay)
            an = min(ax, ay)
            real = log1p((am-1)*(am+1) + an*an) / 2.
        else:
            real = math.log(h)
    imag = math.atan2(y, x)
    return (real, imag)
开发者ID:Debug-Orz,项目名称:Sypy,代码行数:57,代码来源:interp_cmath.py


示例13: sqrt

def sqrt(x):
    """
       Return the square root of x.

       This has the same branch cut as log().
    """
    #   Method: use symmetries to reduce to the case when x = z.real and y
    #   = z.imag are nonnegative.  Then the real part of the result is
    #   given by
    #
    #       s = sqrt((x + hypot(x, y))/2)
    #
    #   and the imaginary part is
    #
    #        d = (y/2)/s
    #
    #   If either x or y is very large then there's a risk of overflow in
    #   computation of the expression x + hypot(x, y).  We can avoid this
    #   by rewriting the formula for s as:
    #
    #       s = 2*sqrt(x/8 + hypot(x/8, y/8))
    #
    #   This costs us two extra multiplications/divisions, but avoids the
    #   overhead of checking for x and y large.
    #   If both x and y are subnormal then hypot(x, y) may also be
    #   subnormal, so will lack full precision.  We solve this by rescaling
    #   x and y by a sufficiently large power of 2 to ensure that x and y
    #   are normal.
    s, d, ax, ay = .0, .0, math.fabs(x.real), math.fabs(x.imag)

    ret = _SPECIAL_VALUE(x, _sqrt_special_values)
    if ret is not None:
        return ret

    if x.real == .0 and x.imag == .0:
        _real = .0
        _imag = x.imag
        return complex(_real,_imag)

    if ax < sys.float_info.min and ay < sys.float_info.min and (ax > 0. or ay > 0.):
        #here we catch cases where hypot(ax, ay) is subnormal
        ax = math.ldexp(ax, _CM_SCALE_UP);
        s = math.ldexp(math.sqrt(ax + math.hypot(ax, math.ldexp(ay, _CM_SCALE_UP))),_CM_SCALE_DOWN)
    else:
        ax /= 8.0;
        s = 2.0*math.sqrt(ax + math.hypot(ax, ay/8.0));

    d = ay/(2.0*s)

    if x.real >= .0:
        _real = s;
        _imag = math.copysign(d, x.imag)
    else:
        _real = d;
        _imag = math.copysign(s, x.imag)

    return complex(_real,_imag)
开发者ID:brython-dev,项目名称:brython,代码行数:57,代码来源:cmath.py


示例14: TakeData

def TakeData():
    t0 = time.clock();
    result = "Test started at " + str(datetime.now()) + "\n";

    LIA1.write("STRT");
    #LIA1.write("STRD"); #start scan after 0.5 sec
    t = time.clock() - t0;
    result += "Scan started at t = " + str(t) + "\n";

    time.sleep(0.5); #32s max
    LIA1.write("PAUS"); #pause
    t = time.clock() - t0;
    result += "Scan ended at t = " + str(t) + "\n";
    LIA1.ask("SPTS ?");
    num = LIA1.ask("SPTS ?"); #number of points
    result += "There are " + num + " points\n";
    t = time.clock() - t0;
    result += "Transfer started at t = " + str(t) + "\n";

    #LIA1.term_chars = "\0";
    CH1 = LIA1.ask_for_values("TRCA ? 1,0," + num);
    CH2 = LIA1.ask_for_values("TRCA ? 2,0," + num);
    LIA1.values_format = visa.single;
    BIN1 = LIA1.ask("TRCL ? 1,0," + num);
    BIN2 = LIA1.ask("TRCL ? 2,0," + num);
    t = time.clock() - t0;
    result += "Transfer ended at t = " + str(t) + "\n";

    BIN1 = list(BIN1);
    BIN2 = list(BIN2);
    CONV1 = list(CH1);
    CONV2 = list(CH2);
    if len(BIN1) != 4*int(num) or len(BIN2) != 4*int(num):
        print "ERROR in num!" + num + "\t" + str(len(BIN1));
        
    for i in range(0,int(num)):
        mantissa = ord(BIN1[4*i+1])*256+ord(BIN1[4*i]);
        if mantissa >= 32768:
            mantissa -= 65536;
        CONV1[i] = math.ldexp(mantissa, ord(BIN1[4*i+2])-124);

        mantissa = ord(BIN2[4*i+1])*256+ord(BIN2[4*i]);
        if mantissa >= 32768:
            mantissa -= 65536;
        CONV2[i] = math.ldexp(mantissa, ord(BIN2[4*i+2])-124);
            
        show = str(CH1[i]) + "\t" + str(CONV1[i]) + \
               "\t" + str(CH2[i]) + "\t" + str(CONV2[i]);
        print show;
        result += show + "\n";

    t = time.clock() - t0;
    result += "Evrything ended at t = " + str(t) + "\n";

    output.write(result);
开发者ID:trort,项目名称:lab_data_collector,代码行数:55,代码来源:bin_verify.py


示例15: __float__

 def __float__(s):
     """Convert s to a Python float. OverflowError will be raised
     if the magnitude of s is too large."""
     try:
         return math.ldexp(s.man, s.exp)
     # Handle case when mantissa has too many bits (will still
     # overflow if exp is too large)
     except OverflowError:
         n = s.bc - 64
         m = s.man >> n
         return math.ldexp(m, s.exp + n)
开发者ID:certik,项目名称:sympy-oldcore,代码行数:11,代码来源:float_.py


示例16: getBoundingBox

def getBoundingBox(x, y, z, dimension, projection):
	#pixel location of the center of the metatile
	x0 = x * TILE_SIZE
	y0 = (y + dimension) * TILE_SIZE
	x1 = (x + dimension) * TILE_SIZE
	y1 = y * TILE_SIZE
	#from pixels to WGS 84, comes back as (lng, lat)
	ul = projection.from_pixels((x0, y0), z)
	lr = projection.from_pixels((x1, y1), z)
	#using ldexp for performant floating point division by 2 to get center pixel location
	center = (int(math.ldexp(x0 + x1, -1) + .5) , int(math.ldexp(y0 + y1, -1) + .5))
	center = projection.from_pixels(center, z)
	return ((ul[1], ul[0]), (lr[1], lr[0])), (center[1], center[0])
开发者ID:abta,项目名称:MapQuest-Render-Stack,代码行数:13,代码来源:tile.py


示例17: c_sqrt

def c_sqrt(x, y):
    '''
    Method: use symmetries to reduce to the case when x = z.real and y
    = z.imag are nonnegative.  Then the real part of the result is
    given by
    
      s = sqrt((x + hypot(x, y))/2)
    
    and the imaginary part is
    
      d = (y/2)/s
    
    If either x or y is very large then there's a risk of overflow in
    computation of the expression x + hypot(x, y).  We can avoid this
    by rewriting the formula for s as:
    
      s = 2*sqrt(x/8 + hypot(x/8, y/8))
    
    This costs us two extra multiplications/divisions, but avoids the
    overhead of checking for x and y large.
    
    If both x and y are subnormal then hypot(x, y) may also be
    subnormal, so will lack full precision.  We solve this by rescaling
    x and y by a sufficiently large power of 2 to ensure that x and y
    are normal.
    '''
    if not isfinite(x) or not isfinite(y):
        return sqrt_special_values[special_type(x)][special_type(y)]

    if x == 0. and y == 0.:
        return (0., y)

    ax = fabs(x)
    ay = fabs(y)

    if ax < DBL_MIN and ay < DBL_MIN and (ax > 0. or ay > 0.):
        # here we catch cases where hypot(ax, ay) is subnormal
        ax = math.ldexp(ax, CM_SCALE_UP)
        ay1= math.ldexp(ay, CM_SCALE_UP)
        s = math.ldexp(math.sqrt(ax + math.hypot(ax, ay1)),
                       CM_SCALE_DOWN)
    else:
        ax /= 8.
        s = 2.*math.sqrt(ax + math.hypot(ax, ay/8.))

    d = ay/(2.*s)

    if x >= 0.:
        return (s, copysign(d, y))
    else:
        return (d, copysign(s, y))
开发者ID:Darriall,项目名称:pypy,代码行数:51,代码来源:rcomplex.py


示例18: read_float

def read_float(s, length):
    t = read(s, length)
    i = byte2num(t)
    if length == 4:
        f = ldexp((i & 0x7fffff) + (1 << 23), (i >> 23 & 0xff) - 150)
        if i & (1 << 31):
            f = -f
    elif length == 8:
        f = ldexp((i & ((1 << 52) - 1)) + (1 << 52), (i >> 52 & 0x7ff) - 1075)
        if i & (1 << 63):
            f = -f
    else:
        raise SyntaxError
    return f
开发者ID:meh,项目名称:mpv,代码行数:14,代码来源:matroska.py


示例19: calc

    def calc(self, irc, msg, args, text):
        """<math expression>

        Returns the value of the evaluated <math expression>.  The syntax is
        Python syntax; the type of arithmetic is floating point.  Floating
        point arithmetic is used in order to prevent a user from being able to
        crash to the bot with something like '10**10**10**10'.  One consequence
        is that large values such as '10**24' might not be exact.
        """
        try:
            text = str(text)
        except UnicodeEncodeError:
            irc.error(_("There's no reason you should have fancy non-ASCII "
                            "characters in your mathematical expression. "
                            "Please remove them."))
            return
        if self._calc_match_forbidden_chars.match(text):
            irc.error(_('There\'s really no reason why you should have '
                           'underscores or brackets in your mathematical '
                           'expression.  Please remove them.'))
            return
        text = self._calc_remover(text)
        if 'lambda' in text:
            irc.error(_('You can\'t use lambda in this command.'))
            return
        text = text.lower()
        def handleMatch(m):
            s = m.group(1)
            if s.startswith('0x'):
                i = int(s, 16)
            elif s.startswith('0') and '.' not in s:
                try:
                    i = int(s, 8)
                except ValueError:
                    i = int(s)
            else:
                i = float(s)
            x = complex(i)
            if x.imag == 0:
                x = x.real
                # Need to use string-formatting here instead of str() because
                # use of str() on large numbers loses information:
                # str(float(33333333333333)) => '3.33333333333e+13'
                # float('3.33333333333e+13') => 33333333333300.0
                return '%.16f' % x
            return str(x)
        text = self._mathRe.sub(handleMatch, text)
        try:
            self.log.info('evaluating %q from %s', text, msg.prefix)
            x = complex(eval(text, self._mathSafeEnv, self._mathSafeEnv))
            irc.reply(self._complexToString(x))
        except OverflowError:
            maxFloat = math.ldexp(0.9999999999999999, 1024)
            irc.error(_('The answer exceeded %s or so.') % maxFloat)
        except TypeError:
            irc.error(_('Something in there wasn\'t a valid number.'))
        except NameError as e:
            irc.error(_('%s is not a defined function.') % str(e).split()[1])
        except Exception as e:
            irc.error(str(e))
开发者ID:limebot,项目名称:LimeBot,代码行数:60,代码来源:plugin.py


示例20: icalc

    def icalc(self, irc, msg, args, text):
        """<math expression>

        This is the same as the calc command except that it allows integer
        math, and can thus cause the bot to suck up CPU.  Hence it requires
        the 'trusted' capability to use.
        """
        if self._calc_match_forbidden_chars.match(text):
            irc.error(
                _(
                    "There's really no reason why you should have "
                    "underscores or brackets in your mathematical "
                    "expression.  Please remove them."
                )
            )
            return
        # This removes spaces, too, but we'll leave the removal of _[] for
        # safety's sake.
        text = self._calc_remover(text)
        if "lambda" in text:
            irc.error(_("You can't use lambda in this command."))
            return
        text = text.replace("lambda", "")
        try:
            self.log.info("evaluating %q from %s", text, msg.prefix)
            irc.reply(str(eval(text, self._mathEnv, self._mathEnv)))
        except OverflowError:
            maxFloat = math.ldexp(0.9999999999999999, 1024)
            irc.error(_("The answer exceeded %s or so.") % maxFloat)
        except TypeError:
            irc.error(_("Something in there wasn't a valid number."))
        except NameError, e:
            irc.error(_("%s is not a defined function.") % str(e).split()[1])
开发者ID:ki113d,项目名称:Limnoria,代码行数:33,代码来源:plugin.py



注:本文中的math.ldexp函数示例由纯净天空整理自Github/MSDocs等源码及文档管理平台,相关代码片段筛选自各路编程大神贡献的开源项目,源码版权归原作者所有,传播和使用请参考对应项目的License;未经允许,请勿转载。


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Python math.lgamma函数代码示例发布时间:2022-05-27
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Python math.isnan函数代码示例发布时间:2022-05-27
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