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List of 1D Continuous Distributions

The following is a list of all 1D continuous distributions currently available in :py:mod:`UQpy`.

Beta

Beta distribution having probability density function

f(x|a,b) = \dfrac{ \Gamma(a+b)x^{a-1}(1-x)^{b-1}}{\Gamma(a) \Gamma(b)}

for 0 \le x \ge 0, a > 0, b > 0. Here \Gamma (a) refers to the Gamma function.

In this standard form (loc=0, scale=1), the distribution is defined over the interval (0, 1). Use loc and scale to shift the distribution to interval (loc, loc + scale). Specifically, this is equivalent to computing f(y|a,b) where y=(x-loc)/scale.

The :class:`.Beta` class is imported using the following command:

>>> from UQpy.distributions.collection.Beta import Beta
.. autoclass:: UQpy.distributions.collection.Beta


Cauchy

Cauchy distribution having probability density function

f(x) = \dfrac{1}{\pi(1+x^2)}

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Cauchy` class is imported using the following command:

>>> from UQpy.distributions.collection.Cauchy import Cauchy
.. autoclass:: UQpy.distributions.collection.Cauchy


Chi Square

Chi-square distribution having probability density:

f(x|k) = \dfrac{1}{2^{k/2}\Gamma(k/2)}x^{k/2-1}\exp{(-x/2)}

for x\ge 0, k>0. Here \Gamma(\cdot) refers to the Gamma function.

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y|k) where y=(x-loc)/scale.

The :class:`.ChiSquare` class is imported using the following command:

>>> from UQpy.distributions.collection.ChiSquare import ChiSquare
.. autoclass:: UQpy.distributions.collection.ChiSquare


Exponential

Exponential distribution having probability density function:

f(x) = \exp(-x)

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

A common parameterization for Exponential is in terms of the rate parameter \lambda, which corresponds to using scale = 1 / \lambda.

The :class:`.Exponential` class is imported using the following command:

>>> from UQpy.distributions.collection.ExponentialCorrelation import Exponential
>>> from UQpy.distributions.collection.ExponentialCorrelation import Exponential
>>> from UQpy.distributions.collection.Exponential import Exponential
.. autoclass:: UQpy.distributions.collection.Exponential


Gamma

Gamma distribution having probability density function:

f(x|a) = \dfrac{x^{a-1}\exp(-x)}{\Gamma(a)}

for x\ge 0, a>0. Here \Gamma(a) refers to the Gamma function.

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Gamma` class is imported using the following command:

>>> from UQpy.distributions.collection.Gamma import Gamma
.. autoclass:: UQpy.distributions.collection.Gamma


Generalized Extreme

Generalized Extreme Value distribution having probability density function:

f(x|c) = \exp(-(1-cx)^{1/c})(1-cx)^{1/c-1}

for x\le 1/c, c>0.

For c=0

f(x) = \exp(\exp(-x))\exp(-x)

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.GeneralizedExtreme` class is imported using the following command:

>>> from UQpy.distributions.collection.GeneralizedExtreme import GeneralizedExtreme
.. autoclass:: UQpy.distributions.collection.GeneralizedExtreme


Inverse Gaussian

Inverse Gaussian distribution having probability density function

f(x|\mu) = \dfrac{1}{2\pi x^3}\exp{(-\dfrac{(x\\mu)^2}{2x\mu^2})}

for x>0. :py:meth:`cdf` method returns NaN for \mu<0.0028.

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.InverseGauss` class is imported using the following command:

>>> from UQpy.distributions.collection.InverseGaussian import InverseGauss
.. autoclass:: UQpy.distributions.collection.InverseGauss


Laplace

Laplace distribution having probability density function

f(x) = \dfrac{1}{2}\exp{-|x|}

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Laplace` class is imported using the following command:

>>> from UQpy.distributions.collection.Laplace import Laplace
.. autoclass:: UQpy.distributions.collection.Laplace


Levy

Levy distribution having probability density function

f(x) = \dfrac{1}{\sqrt{2\pi x^3}}\exp(-\dfrac{1}{2x})

for x\ge 0.

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Levy` class is imported using the following command:

>>> from UQpy.distributions.collection.Levy import Levy
.. autoclass:: UQpy.distributions.collection.Levy


Logistic

Logistic distribution having probability density function

f(x) = \dfrac{\exp(-x)}{(1+\exp(-x))^2}

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Logistic` class is imported using the following command:

>>> from UQpy.distributions.collection.Logistic import Logistic
.. autoclass:: UQpy.distributions.collection.Logistic


Lognormal

Lognormal distribution having probability density function

f(x|s) = \dfrac{1}{sx\sqrt{2\pi}}\exp(-\dfrac{\log^2(x)}{2s^2})

for x>0, s>0.

A common parametrization for a lognormal random variable Y is in terms of the mean, mu, and standard deviation, sigma, of the gaussian random variable X such that exp(X) = Y. This parametrization corresponds to setting s = sigma and scale = exp(mu).

The :class:`.Lognormal` class is imported using the following command:

>>> from UQpy.distributions.collection.Lognormal import Lognormal
.. autoclass:: UQpy.distributions.collection.Lognormal


Maxwell

Maxwell-Boltzmann distribution having probability density function

f(x) = \sqrt{2/\pi}x^2\exp(-x^2/2)

for x\ge0.

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Maxwell` class is imported using the following command:

>>> from UQpy.distributions.collection.Maxwell import Maxwell
.. autoclass:: UQpy.distributions.collection.Maxwell


Normal

Normal distribution having probability density function

f(x) = \dfrac{\exp(-x^2/2)}{\sqrt{2\pi}}

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Normal` class is imported using the following command:

>>> from UQpy.distributions.collection.Normal import Normal
.. autoclass:: UQpy.distributions.collection.Normal


Pareto

Pareto distribution having probability density function

f(x|b) = \dfrac{b}{x^{b+1}}

for x\ge 1, b>0.

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Pareto` class is imported using the following command:

>>> from UQpy.distributions.collection.Pareto import Pareto
.. autoclass:: UQpy.distributions.collection.Pareto


Rayleigh

Rayleigh distribution having probability density function

f(x) = x\exp(-x^2/2)

for x\ge 0.

In this standard form (loc=0, scale=1). Use loc and scale to shift and scale the distribution. Specifically, this is equivalent to computing f(y) where y=(x-loc)/scale.

The :class:`.Rayleigh` class is imported using the following command:

>>> from UQpy.distributions.collection.Rayleigh import Rayleigh
.. autoclass:: UQpy.distributions.collection.Rayleigh


Truncated Normal

Truncated normal distribution

The standard form of this distribution (loc=0, scale=1) is a standard normal truncated to the range [a, b]. Note that a and b are defined over the domain of the standard normal.

The :class:`.TruncatedNormal` class is imported using the following command:

>>> from UQpy.distributions.collection.TruncatedNormal import TruncatedNormal
.. autoclass:: UQpy.distributions.collection.TruncatedNormal


Uniform

Uniform distribution having probability density function

f(x|a, b) = \dfrac{1}{b-a}

where a=loc and b=loc+scale

The :class:`.Uniform` class is imported using the following command:

>>> from UQpy.distributions.collection.Uniform import Uniform
.. autoclass:: UQpy.distributions.collection.Uniform