openmc.stats.Watt

class openmc.stats.Watt(a=988000.0, b=2.249e-06, bias: Univariate | None = None)[source]

Watt fission energy spectrum.

The Watt fission energy spectrum is characterized by two parameters \(a\) and \(b\) and has density function \(p(E) dE = c e^{-E/a} \sinh \sqrt{b \, E} dE\).

Parameters:

  • a (float) – First parameter of distribution in units of eV

  • b (float) – Second parameter of distribution in units of 1/eV

  • bias (openmc.stats.Univariate, optional) – Distribution for biased sampling.

Variables:

  • a (float) – First parameter of distribution in units of eV

  • b (float) – Second parameter of distribution in units of 1/eV

  • support (tuple of float) – A 2-tuple (lower, upper) defining the interval over which the distribution is nonzero-valued

  • bias (openmc.stats.Univariate or None) – Distribution for biased sampling

evaluate(E)[source]

Evaluate the probability density at the provided value.

Parameters:

x (float or sequence of float) – Location to evaluate p(x)

Returns:

Value of p(x)

Return type:

float or numpy.ndarray

classmethod from_xml_element(elem: Element)[source]

Generate Watt distribution from an XML element

Parameters:

elem (lxml.etree._Element) – XML element

Returns:

Watt distribution generated from XML element

Return type:

openmc.stats.Watt

property support

Return the support of the probability distribution.

Returns:

Returns the set of unique points assigned probability mass in a discrete distribution, the sampling interval for a continuous distribution, or a dictionary storing the discrete and continuous parts of the support of a mixed random variable

Return type:

set or tuple of float or dict

to_xml_element(element_name: str)[source]

Return XML representation of the Watt distribution

Parameters:

element_name (str) – XML element name

Returns:

element – XML element containing Watt distribution data

Return type:

lxml.etree._Element