# nifty7.library.special_distributions module#

InverseGammaOperator(domain, alpha, q, delta=0.01)[source]#

Transform a standard normal into an inverse gamma distribution.

The pdf of the inverse gamma distribution is defined as follows:

That means that for large x the pdf falls off like . The mean of the pdf is at if . The mode is .

This transformation is implemented as a linear interpolation which maps a Gaussian onto an inverse gamma distribution.

Parameters:
• domain (Domain, tuple of Domain or DomainTuple) – The domain on which the field shall be defined. This is at the same time the domain and the target of the operator.

• alpha (float) – The alpha-parameter of the inverse-gamma distribution.

• q (float or Field) – The q-parameter of the inverse-gamma distribution.

• delta (float) – Distance between sampling points for linear interpolation.

class LaplaceOperator(domain, loc=0, scale=1)[source]#

Bases: Operator

Transform a standard normal to a Laplace distribution.

Parameters:
• domain (Domain, tuple of Domain or DomainTuple) – The domain on which the field shall be defined. This is at the same time the domain and the target of the operator.

• loc (float) –

• scale (float) –

apply(x)[source]#

Applies the operator to a Field or MultiField.

Parameters:

x (Field or MultiField) – Input on which the operator shall act. Needs to be defined on domain.

inverse(x)[source]#

Transform a standard normal into the log of an inverse gamma distribution.

class UniformOperator(domain, loc=0, scale=1)[source]#

Bases: Operator

Transform a standard normal into a uniform distribution.

The uniform distribution’s support is [loc, loc + scale].

Parameters:
• domain (Domain, tuple of Domain or DomainTuple) – The domain on which the field shall be defined. This is at the same time the domain and the target of the operator.

• loc (float) –

• scale (float) –

apply(x)[source]#

Applies the operator to a Field or MultiField.

Parameters:

x (Field or MultiField) – Input on which the operator shall act. Needs to be defined on domain.

inverse(field)[source]#