"""Standard deviation."""
import numpy
from .variance import Var
[docs]def Std(poly, dist=None, **kws):
"""
Standard deviation.
Args:
poly (numpoly.ndpoly, Distribution):
Input to take variance on.
dist (Distribution):
Defines the space the variance is taken on. It is ignored if
``poly`` is a distribution.
Returns:
(numpy.ndarray):
Element for element variance along ``poly``, where
``variation.shape == poly.shape``.
Examples:
>>> dist = chaospy.J(chaospy.Gamma(1, 1), chaospy.Normal(0, 2))
>>> chaospy.Std(dist)
array([1., 2.])
>>> q0, q1 = chaospy.variable(2)
>>> poly = chaospy.polynomial([1, q0, q1, 10*q0*q1-1])
>>> chaospy.Std(poly, dist)
array([ 0. , 1. , 2. , 28.28427125])
"""
return numpy.sqrt(Var(poly, dist=dist, **kws))