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Per.Andreas.Brodtkorb 12 years ago
parent ffc1721a6a
commit 003da7070f
2 changed files with 81 additions and 40 deletions
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105
pywafo/src/wafo/stats/distributions.py
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@ -31,7 +31,7 @@ import numpy as np
import numpy.random as mtrand import numpy.random as mtrand
from numpy import flatnonzero as nonzero from numpy import flatnonzero as nonzero
_log1p = log1p
from wafo.stats.estimation import FitDistribution from wafo.stats.estimation import FitDistribution
@ -88,6 +88,10 @@ except ImportError:
def instancemethod(func, obj, cls): def instancemethod(func, obj, cls):
return types.MethodType(func, obj) return types.MethodType(func, obj)
def log1p(x):
'''avoids warnings for x==-1'''
mx = where(x==-1, 0, x)
return where(x==-1, -inf, _log1p(mx))
# These are the docstring parts used for substitution in specific # These are the docstring parts used for substitution in specific
# distribution docstrings. # distribution docstrings.
@ -1073,18 +1077,20 @@ class rv_generic(object):
The shape parameter(s) for the distribution (see docstring of the The shape parameter(s) for the distribution (see docstring of the
instance object for more information) instance object for more information)
loc : array_like, optional loc : array_like, optional
location parameter (default=0) Location parameter, Default is 0.
scale : array_like, optional scale : array_like, optional
scale parameter (default=1) Scale parameter, Default is 1.
Returns Returns
------- -------
median : float median : float
the median of the distribution. The median of the distribution.
See Also See Also
-------- --------
self.ppf --- inverse of the CDF stats.distributions.rv_discrete.ppf
Inverse of the CDF
""" """
return self.ppf(0.5, *args, **kwds) return self.ppf(0.5, *args, **kwds)
@ -1164,24 +1170,28 @@ class rv_generic(object):
return res return res
def interval(self, alpha, *args, **kwds): def interval(self, alpha, *args, **kwds):
"""Confidence interval with equal areas around the median """
Confidence interval with equal areas around the median.
Parameters Parameters
---------- ----------
alpha : array_like float in [0,1] alpha : array_like of float
Probability that an rv will be drawn from the returned range Probability that an rv will be drawn from the returned range.
Each value should be in the range [0, 1].
arg1, arg2, ... : array_like arg1, arg2, ... : array_like
The shape parameter(s) for the distribution (see docstring of the instance The shape parameter(s) for the distribution (see docstring of the
object for more information) instance object for more information).
loc : array_like, optional loc : array_like, optional
location parameter (default = 0) location parameter, Default is 0.
scale : array_like, optional scale : array_like, optional
scale paramter (default = 1) scale parameter, Default is 1.
Returns Returns
------- -------
a, b : array_like (float) a, b : ndarray of float
end-points of range that contain alpha % of the rvs end-points of range that contain ``100 * alpha %`` of the rv's possible
values.
""" """
alpha = asarray(alpha) alpha = asarray(alpha)
if any((alpha > 1) | (alpha < 0)): if any((alpha > 1) | (alpha < 0)):
@ -1393,7 +1403,6 @@ class rv_continuous(rv_generic):
Alternatively, you can override ``_munp``, which takes n and shape Alternatively, you can override ``_munp``, which takes n and shape
parameters and returns the nth non-central moment of the distribution. parameters and returns the nth non-central moment of the distribution.
Examples Examples
-------- --------
To create a new Gaussian distribution, we would do the following:: To create a new Gaussian distribution, we would do the following::
@ -1728,7 +1737,7 @@ class rv_continuous(rv_generic):
def cdf(self,x,*args,**kwds): def cdf(self,x,*args,**kwds):
""" """
Cumulative distribution function at x of the given RV. Cumulative distribution function of the given RV.
Parameters Parameters
---------- ----------
@ -1744,8 +1753,8 @@ class rv_continuous(rv_generic):
Returns Returns
------- -------
cdf : array_like cdf : ndarray
Cumulative distribution function evaluated at x Cumulative distribution function evaluated at `x`
""" """
loc,scale=map(kwds.get,['loc','scale']) loc,scale=map(kwds.get,['loc','scale'])
@ -1967,8 +1976,8 @@ class rv_continuous(rv_generic):
Returns Returns
------- -------
x : array_like x : ndarray or scalar
quantile corresponding to the upper tail probability q. Quantile corresponding to the upper tail probability q.
""" """
loc,scale=map(kwds.get,['loc','scale']) loc,scale=map(kwds.get,['loc','scale'])
@ -1998,7 +2007,6 @@ class rv_continuous(rv_generic):
proxy_value = extract(cond2, proxy_value * cond2) proxy_value = extract(cond2, proxy_value * cond2)
place(output, cond2, proxy_value) place(output, cond2, proxy_value)
if any(cond): #call only if at least 1 entry if any(cond): #call only if at least 1 entry
goodargs = argsreduce(cond, *((q,)+args+(scale,loc))) #PB replace 1-q by q goodargs = argsreduce(cond, *((q,)+args+(scale,loc))) #PB replace 1-q by q
scale, loc, goodargs = goodargs[-2], goodargs[-1], goodargs[:-2] scale, loc, goodargs = goodargs[-2], goodargs[-1], goodargs[:-2]
@ -2597,6 +2605,7 @@ class rv_continuous(rv_generic):
Estimated location parameter for the data. Estimated location parameter for the data.
Shat : float Shat : float
Estimated scale parameter for the data. Estimated scale parameter for the data.
""" """
mu, mu2 = self.stats(*args,**{'moments':'mv'}) mu, mu2 = self.stats(*args,**{'moments':'mv'})
tmp = asarray(data) tmp = asarray(data)
@ -7057,7 +7066,7 @@ class rv_discrete(rv_generic):
def cdf(self, k, *args, **kwds): def cdf(self, k, *args, **kwds):
""" """
Cumulative distribution function at k of the given RV. Cumulative distribution function of the given RV.
Parameters Parameters
---------- ----------
@ -7071,8 +7080,8 @@ class rv_discrete(rv_generic):
Returns Returns
------- -------
cdf : array_like cdf : ndarray
Cumulative distribution function evaluated at k. Cumulative distribution function evaluated at `k`.
""" """
loc = kwds.get('loc') loc = kwds.get('loc')
@ -7177,7 +7186,10 @@ class rv_discrete(rv_generic):
def logsf(self,k,*args,**kwds): def logsf(self,k,*args,**kwds):
""" """
Log of the survival function (1-cdf) at k of the given RV Log of the survival function of the given RV.
Returns the log of the "survival function," defined as ``1 - cdf``,
evaluated at `k`.
Parameters Parameters
---------- ----------
@ -7191,8 +7203,8 @@ class rv_discrete(rv_generic):
Returns Returns
------- -------
sf : array_like sf : ndarray
Survival function evaluated at k. Survival function evaluated at `k`.
""" """
loc= kwds.get('loc') loc= kwds.get('loc')
@ -7274,11 +7286,10 @@ class rv_discrete(rv_generic):
Returns Returns
------- -------
k : array_like k : ndarray or scalar
Quantile corresponding to the upper tail probability, q. Quantile corresponding to the upper tail probability, q.
""" """
loc = kwds.get('loc') loc = kwds.get('loc')
args, loc = self.fix_loc(args, loc) args, loc = self.fix_loc(args, loc)
q,loc = map(asarray,(q,loc)) q,loc = map(asarray,(q,loc))
@ -7435,7 +7446,7 @@ class rv_discrete(rv_generic):
---------- ----------
n : int, n>=1 n : int, n>=1
order of moment order of moment
arg1, arg2, arg3,...: float arg1, arg2, arg3,... : float
The shape parameter(s) for the distribution (see docstring of the The shape parameter(s) for the distribution (see docstring of the
instance object for more information) instance object for more information)
loc : float, optional loc : float, optional
@ -7514,7 +7525,8 @@ class rv_discrete(rv_generic):
return self.freeze(*args,**kwds) return self.freeze(*args,**kwds)
def expect(self, func=None, args=(), loc=0, lb=None, ub=None, conditional=False): def expect(self, func=None, args=(), loc=0, lb=None, ub=None, conditional=False):
"""calculate expected value of a function with respect to the distribution """
Calculate expected value of a function with respect to the distribution
for discrete distribution for discrete distribution
Parameters Parameters
@ -7523,11 +7535,11 @@ class rv_discrete(rv_generic):
Function for which sum is calculated. Takes only one argument. Function for which sum is calculated. Takes only one argument.
args : tuple args : tuple
argument (parameters) of the distribution argument (parameters) of the distribution
optional keyword parameters lb, ub : numbers, optional
lb, ub : numbers
lower and upper bound for integration, default is set to the support lower and upper bound for integration, default is set to the support
of the distribution, lb and ub are inclusive (ul<=k<=ub) of the distribution, lb and ub are inclusive (ul<=k<=ub)
conditional : boolean (False) conditional : bool, optional
Default is False.
If true then the expectation is corrected by the conditional If true then the expectation is corrected by the conditional
probability of the integration interval. The return value is the probability of the integration interval. The return value is the
expectation of the function, conditional on being in the given expectation of the function, conditional on being in the given
@ -7535,7 +7547,8 @@ class rv_discrete(rv_generic):
Returns Returns
------- -------
expected value : float expect : float
Expected value.
Notes Notes
----- -----
@ -7549,8 +7562,8 @@ class rv_discrete(rv_generic):
non-monotonic shapes, points include integers in (-suppnmin, suppnmin) non-monotonic shapes, points include integers in (-suppnmin, suppnmin)
* uses maxcount=1000 limits the number of points that are evaluated * uses maxcount=1000 limits the number of points that are evaluated
to break loop for infinite sums to break loop for infinite sums
(a maximum of suppnmin+1000 positive plus suppnmin+1000 negative integers (a maximum of suppnmin+1000 positive plus suppnmin+1000 negative
are evaluated) integers are evaluated)
""" """
@ -7658,9 +7671,12 @@ class binom_gen(rv_discrete):
"Fast and Accurate Computation of Binomial Probabilities"; "Fast and Accurate Computation of Binomial Probabilities";
url = "http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.35.2719" } url = "http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.35.2719" }
""" """
logp = where((p==0) & (x==0), 1, log(p))
log1mp = where((p==1) & (x==n), 1, log1p(-p))
PI2 = 2.0 * pi PI2 = 2.0 * pi
yborder = log((x == 0.) * exp(n * log1p(-p)) + (x == n) * exp(n * log(p))) yborder = log((x == 0.) * exp(n * log1mp) + (x == n) * exp(n * logp))
nx = n - x nx = n - x
nq = n * (1. - p) nq = n * (1. - p)
lc = stirlerr(n) - stirlerr(x) - stirlerr(nx) - bd0(x, n * p) - bd0(nx, nq) lc = stirlerr(n) - stirlerr(x) - stirlerr(nx) - bd0(x, n * p) - bd0(nx, nq)
@ -7669,7 +7685,6 @@ class binom_gen(rv_discrete):
return where(inside, lc + 0.5 * log(n / (PI2 * xnx)), yborder) return where(inside, lc + 0.5 * log(n / (PI2 * xnx)), yborder)
def _pmf(self, x, n, p): def _pmf(self, x, n, p):
return exp(self._logpmf(x, n, p)) return exp(self._logpmf(x, n, p))
def _cdf(self, x, n, p): def _cdf(self, x, n, p):
k = floor(x) k = floor(x)
vals = special.bdtr(k,n,p) vals = special.bdtr(k,n,p)
@ -8457,7 +8472,17 @@ def test_genpareto():
print(phat.par) print(phat.par)
if __name__ == '__main__': if __name__ == '__main__':
bernoulli.logcdf(np.nan) import matplotlib
matplotlib.use()
import matplotlib.pyplot as plt
prb = np.linspace(0,1, 10)
q = truncnorm.isf(prb,-1., 1., loc=[3],scale=2)
plt.plot(q, prb)
plt.show()
p = truncnorm.sf(q,-1,1, loc=[3],scale=2)
pass
#bernoulli.logcdf(np.nan)
#test_binom() #test_binom()
#test_doctstrings() #test_doctstrings()
#test_genpareto() #test_genpareto()

16
pywafo/src/wafo/stats/tests/test_distributions.py
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@ -235,6 +235,22 @@ class TestGeom(TestCase):
assert_array_almost_equal(vals,expected) assert_array_almost_equal(vals,expected)
assert_array_almost_equal(vals_sf,1-expected) assert_array_almost_equal(vals_sf,1-expected)
class TestTruncnorm(TestCase):
def test_ppf_ticket1131(self):
vals = stats.truncnorm.ppf([-0.5,0,1e-4,0.5, 1-1e-4,1,2],-1., 1.,
loc=[3]*7,scale=2)
NaN = np.NaN
expected = np.array([ NaN, 1. , 1.00056419, 3.
, 4.99943581, 5. , NaN])
assert_array_almost_equal(vals, expected)
def test_isf_ticket1131(self):
NaN = np.NaN
vals = stats.truncnorm.isf([-0.5,0,1e-4,0.5, 1-1e-4,1,2],-1., 1.,
loc=[3]*7,scale=2)
expected = np.array([ NaN, 5. , 4.99943581, 3.,
1.00056419, 1. , NaN])
assert_array_almost_equal(vals, expected)
class TestHypergeom(TestCase): class TestHypergeom(TestCase):
def test_rvs(self): def test_rvs(self):

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