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authorrgommers <ralf.gommers@googlemail.com>2010-07-26 14:06:51 +0000
committerrgommers <ralf.gommers@googlemail.com>2010-07-26 14:06:51 +0000
commitdc3aa189d6941c628fe493c78cf471b2a1cc5ba9 (patch)
tree8401e2398d1444109ffb2f6630b1a6543552d75b
parentfa0842ffa749a00d0573f7ab803db450b9d1c7c7 (diff)
downloadnumpy-dc3aa189d6941c628fe493c78cf471b2a1cc5ba9.tar.gz
DOC: Merge wiki changes for RandomState as far as possible. Closes #1503.
-rw-r--r--numpy/random/mtrand/mtrand.pyx126
1 files changed, 69 insertions, 57 deletions
diff --git a/numpy/random/mtrand/mtrand.pyx b/numpy/random/mtrand/mtrand.pyx
index 13aa111b2..f3caac14b 100644
--- a/numpy/random/mtrand/mtrand.pyx
+++ b/numpy/random/mtrand/mtrand.pyx
@@ -762,15 +762,17 @@ cdef class RandomState:
"""
tomaxint(size=None)
- Uniformly sample discrete random integers `x` such that
- ``0 <= x <= sys.maxint``.
+ Random integers between 0 and ``sys.maxint``, inclusive.
+
+ Return a sample of uniformly distributed random integers in the interval
+ [0, ``sys.maxint``].
Parameters
----------
size : tuple of ints, int, optional
- Shape of output. If the given size is, for example, (m,n,k),
- m*n*k samples are generated. If no shape is specified, a single sample
- is returned.
+ Shape of output. If this is, for example, (m,n,k), m*n*k samples
+ are generated. If no shape is specified, a single sample is
+ returned.
Returns
-------
@@ -783,6 +785,23 @@ cdef class RandomState:
random_integers : Uniform sampling over a given closed interval of
integers.
+ Examples
+ --------
+ >>> RS = np.random.mtrand.RandomState() # need a RandomState object
+ >>> RS.tomaxint((2,2,2))
+ array([[[1170048599, 1600360186],
+ [ 739731006, 1947757578]],
+ [[1871712945, 752307660],
+ [1601631370, 1479324245]]])
+ >>> import sys
+ >>> sys.maxint
+ 2147483647
+ >>> RS.tomaxint((2,2,2)) < sys.maxint
+ array([[[ True, True],
+ [ True, True]],
+ [[ True, True],
+ [ True, True]]], dtype=bool)
+
"""
return disc0_array(self.internal_state, rk_long, size)
@@ -1805,10 +1824,10 @@ cdef class RandomState:
Draw samples from a chi-square distribution.
- When `df` independent random variables, each with standard
- normal distributions (mean 0, variance 1), are squared and summed,
- the resulting distribution is chi-square (see Notes). This
- distribution is often used in hypothesis testing.
+ When `df` independent random variables, each with standard normal
+ distributions (mean 0, variance 1), are squared and summed, the
+ resulting distribution is chi-square (see Notes). This distribution
+ is often used in hypothesis testing.
Parameters
----------
@@ -1852,10 +1871,8 @@ cdef class RandomState:
References
----------
- .. [1] NIST/SEMATECH e-Handbook of Statistical Methods,
- http://www.itl.nist.gov/div898/handbook/eda/section3/eda3666.htm
- .. [2] Wikipedia, "Chi-square distribution",
- http://en.wikipedia.org/wiki/Chi-square_distribution
+ `NIST/SEMATECH e-Handbook of Statistical Methods
+ <http://www.itl.nist.gov/div898/handbook/eda/section3/eda3666.htm>`_
Examples
--------
@@ -2135,36 +2152,37 @@ cdef class RandomState:
def vonmises(self, mu, kappa, size=None):
"""
- vonmises(mu=0.0, kappa=1.0, size=None)
+ vonmises(mu, kappa, size=None)
Draw samples from a von Mises distribution.
- Samples are drawn from a von Mises distribution with specified mode (mu)
- and dispersion (kappa), on the interval [-pi, pi].
+ Samples are drawn from a von Mises distribution with specified mode
+ (mu) and dispersion (kappa), on the interval [-pi, pi].
The von Mises distribution (also known as the circular normal
- distribution) is a continuous probability distribution on the circle. It
- may be thought of as the circular analogue of the normal distribution.
+ distribution) is a continuous probability distribution on the unit
+ circle. It may be thought of as the circular analogue of the normal
+ distribution.
Parameters
----------
mu : float
Mode ("center") of the distribution.
- kappa : float, >= 0.
- Dispersion of the distribution.
- size : {tuple, int}
+ kappa : float
+ Dispersion of the distribution, has to be >=0.
+ size : int or tuple of int
Output shape. If the given shape is, e.g., ``(m, n, k)``, then
``m * n * k`` samples are drawn.
Returns
-------
- samples : {ndarray, scalar}
- The returned samples live on the unit circle [-\\pi, \\pi].
+ samples : scalar or ndarray
+ The returned samples, which are in the interval [-pi, pi].
See Also
--------
scipy.stats.distributions.vonmises : probability density function,
- distribution or cumulative density function, etc.
+ distribution, or cumulative density function, etc.
Notes
-----
@@ -2175,21 +2193,19 @@ cdef class RandomState:
where :math:`\\mu` is the mode and :math:`\\kappa` the dispersion,
and :math:`I_0(\\kappa)` is the modified Bessel function of order 0.
- The von Mises, named for Richard Edler von Mises, born in
- Austria-Hungary, in what is now the Ukraine. He fled to the United
- States in 1939 and became a professor at Harvard. He worked in
+ The von Mises is named for Richard Edler von Mises, who was born in
+ Austria-Hungary, in what is now the Ukraine. He fled to the United
+ States in 1939 and became a professor at Harvard. He worked in
probability theory, aerodynamics, fluid mechanics, and philosophy of
science.
References
----------
- .. [1] Abramowitz, M. and Stegun, I. A. (ed.), Handbook of Mathematical
- Functions, National Bureau of Standards, 1964; reprinted Dover
- Publications, 1965.
- .. [2] von Mises, Richard, 1964, Mathematical Theory of Probability
- and Statistics (New York: Academic Press).
- .. [3] Wikipedia, "Von Mises distribution",
- http://en.wikipedia.org/wiki/Von_Mises_distribution
+ Abramowitz, M. and Stegun, I. A. (ed.), *Handbook of Mathematical
+ Functions*, New York: Dover, 1965.
+
+ von Mises, R., *Mathematical Theory of Probability and Statistics*,
+ New York: Academic Press, 1964.
Examples
--------
@@ -3477,31 +3493,34 @@ cdef class RandomState:
Draw samples from a Zipf distribution.
- Samples are drawn from a Zipf distribution with specified parameter (a),
- where a > 1.
+ Samples are drawn from a Zipf distribution with specified parameter
+ `a` > 1.
- The zipf distribution (also known as the zeta
- distribution) is a continuous probability distribution that satisfies
- Zipf's law, where the frequency of an item is inversely proportional to
- its rank in a frequency table.
+ The Zipf distribution (also known as the zeta distribution) is a
+ continuous probability distribution that satisfies Zipf's law: the
+ frequency of an item is inversely proportional to its rank in a
+ frequency table.
Parameters
----------
- a : float
- parameter, > 1.
- size : {tuple, int}
+ a : float > 1
+ Distribution parameter.
+ size : int or tuple of int, optional
Output shape. If the given shape is, e.g., ``(m, n, k)``, then
- ``m * n * k`` samples are drawn.
+ ``m * n * k`` samples are drawn; a single integer is equivalent in
+ its result to providing a mono-tuple, i.e., a 1-D array of length
+ *size* is returned. The default is None, in which case a single
+ scalar is returned.
Returns
-------
- samples : {ndarray, scalar}
+ samples : scalar or ndarray
The returned samples are greater than or equal to one.
See Also
--------
scipy.stats.distributions.zipf : probability density function,
- distribution or cumulative density function, etc.
+ distribution, or cumulative density function, etc.
Notes
-----
@@ -3511,21 +3530,14 @@ cdef class RandomState:
where :math:`\\zeta` is the Riemann Zeta function.
- Named after the American linguist George Kingsley Zipf, who noted that
- the frequency of any word in a sample of a language is inversely
+ It is named for the American linguist George Kingsley Zipf, who noted
+ that the frequency of any word in a sample of a language is inversely
proportional to its rank in the frequency table.
-
References
----------
- .. [1] Weisstein, Eric W. "Zipf Distribution." From MathWorld--A Wolfram
- Web Resource. http://mathworld.wolfram.com/ZipfDistribution.html
- .. [2] Wikipedia, "Zeta distribution",
- http://en.wikipedia.org/wiki/Zeta_distribution
- .. [3] Wikipedia, "Zipf's Law",
- http://en.wikipedia.org/wiki/Zipf%27s_law
- .. [4] Zipf, George Kingsley (1932): Selected Studies of the Principle
- of Relative Frequency in Language. Cambridge (Mass.).
+ Zipf, G. K., *Selected Studies of the Principle of Relative Frequency
+ in Language*, Cambridge, MA: Harvard Univ. Press, 1932.
Examples
--------