Except when explicitly noted otherwise, all return values are floats. 9.2.1. Created using Sphinx 1.2.2. Numeric and Mathematical Modules » | 9.2. math -- Mathematical functionsÂ¶ This module is always available. Comp. 23 (107): 631â€“637.

J. (March 1993), "Algorithm 715: SPECFUNâ€”A portable FORTRAN package of special function routines and test drivers" (PDF), ACM Trans. Thanks Allen Downey 6 May 2010 at 08:50 Thanks for this -- I would like to distribute a modified version of this code -- can you tell me what license you This is the length of the vector from the origin to point (x, y). Java: Apache commons-math[19] provides implementations of erf and erfc for real arguments.

Based on your numbers I'm going with scipy.special.erf. The Q-function can be expressed in terms of the error function as Q ( x ) = 1 2 − 1 2 erf ( x 2 ) = 1 2 The maximum error is below 1.5 Ã— 10-7.import math def erf(x): # constants a1 = 0.254829592 a2 = -0.284496736 a3 = 1.421413741 a4 = -1.453152027 a5 = 1.061405429 p = 0.3275911 Matlab provides both erf and erfc for real arguments, also via W.

E.g setting axis labels. Unlike the built-in ** operator, math.pow() converts both its arguments to type float. Delegates to x.__trunc__(). Number-theoretic and representation functionsÂ¶ math.ceil(x)Â¶ Return the ceiling of x, the smallest integer greater than or equal to x.

Generate a 6 character string from a 15 character alphabet How to deal with sewage on a map with no water anywhere Karger's Algorithm question more hot questions question feed lang-py But directly evaluating an nth order polynomial takes O(n2) operations, while the factorization used in the code above uses O(n) operations. Special functions 9.2.7. It can be seen from the plot that the two functions sum to unity.

python python-2.7 python-3.x numpy share|improve this question asked Jul 7 '15 at 10:37 Naitik Mathur 442 closed as unclear what you're asking by jonrsharpe, ekad, cel, HaveNoDisplayName, Soner Gönül Jul 7 Specifically, NaN is not considered close to any other value, including NaN. inf and -inf are only considered close to themselves. Plotting using matplotlib In[2]: %matplotlib inline import numpy as np import matplotlib.pyplot as plt x = np.linspace(0, 4*np.pi, 64) plt.plot(x, np.sin(x), '*-'); We can improve on the above plot in several Is there a python package with no external dependencies that contains an implementation of this function?

The result is between -pi and pi. For further discussion and two alternative approaches, see the ASPN cookbook recipes for accurate floating point summation. The defining integral cannot be evaluated in closed form in terms of elementary functions, but by expanding the integrand eâˆ’z2 into its Maclaurin series and integrating term by term, one obtains doi:10.1090/S0025-5718-1969-0247736-4. ^ Error Function and Fresnel Integrals, SciPy v0.13.0 Reference Guide. ^ R Development Core Team (25 February 2011), R: The Normal Distribution Further reading[edit] Abramowitz, Milton; Stegun, Irene Ann, eds.

Does chilli get milder with cooking? With the following setup: from scipy.special import erf; import numpy as np; data = np.random.randn(10e5), I get very fast runtimes from: result = erf(data). Cody's algorithm.[20] Maxima provides both erf and erfc for real and complex arguments. Cook 22.1k75888 This code gives a division-by-zero error for erf(0.0). –rog Jan 19 '09 at 15:56 You're right.

Number-theoretic and representation functions 9.2.2. Why doesn't ${@:-1} return the last element of [email protected]? If x is not a float, delegates to x.__floor__(), which should return an Integral value. The case with \(n = 1\) is also given by e1().

Number-theoretic and representation functions 9.2.2. For the ceil(), floor(), and modf() functions, note that all floating-point numbers of sufficiently large magnitude are exact integers. Examples Some basic values and limits: >>> from mpmath import * >>> mp.dps = 25; mp.pretty = True >>> fresnels(0) 0.0 >>> fresnels(inf) 0.5 >>> fresnels(-inf) -0.5 >>> fresnels(1) 0.4382591473903547660767567 >>> math.isinf(x)Â¶ Return True if x is a positive or negative infinity, and False otherwise.

See also int.bit_length() returns the number of bits necessary to represent an integer in binary, excluding the sign and leading zeros. LCCN65-12253. Typical behavior is to treat all NaNs as though they were quiet. Flat is better than nested.

Alternatively, li(x, offset=True) computes the offset logarithmic integral (used in number theory) \[\mathrm{Li}(x) = \int_2^x \frac{1}{\log t} \, dt.\] These two functions are related via the simple identity \(\mathrm{Li}(x) = \mathrm{li}(x) Created using Sphinx 1.0.7. Cody's rational Chebyshev approximation algorithm.[20] Ruby: Provides Math.erf() and Math.erfc() for real arguments. In Harry Potter book 7, why didn't the Order flee Britain after Harry turned seventeen?

For example, to set a tolerance of 5%, pass rel_tol=0.05. For reasons I don't understand, Microsoft does implement Bessel functions, but it doesn't implement function that I imagine are more commonly used, particularly the gamma function. The erf function lies in scipy. >>>from scipy.special import erf >>>help(erf) You can also use the erf function defined in pylab, but this is more intended at plotting the results of At the imaginary axis, it tends to Â±iâˆž.

New in version 3.2. Export The $PATH Variable, Line-By-Line Why do train companies require two hours to deliver your ticket to the machine? Retrieved 2011-10-03. ^ Chiani, M., Dardari, D., Simon, M.K. (2003). Unless explicitly silenced.

M. This is used to "pick apart" the internal representation of a float in a portable way.