entropy#
- Uniform.entropy(*, method=None)[source]#
Differential entropy
In terms of probability density function \(f(x)\) and support \(\chi\), the differential entropy (or simply “entropy”) of a continuous random variable \(X\) is:
\[h(X) = - \int_{\chi} f(x) \log f(x) dx\]- Parameters:
- method{None, ‘formula’, ‘logexp’, ‘quadrature’}
The strategy used to evaluate the entropy. By default (
None
), the infrastructure chooses between the following options, listed in order of precedence.'formula'
: use a formula for the entropy itself'logexp'
: evaluate the log-entropy and exponentiate'quadrature'
: use numerical integration
Not all method options are available for all distributions. If the selected method is not available, a
NotImplementedError
will be raised.
- Returns:
- outarray
The entropy of the random variable.
See also
Notes
This function calculates the entropy using the natural logarithm; i.e. the logarithm with base \(e\). Consequently, the value is expressed in (dimensionless) “units” of nats. To convert the entropy to different units (i.e. corresponding with a different base), divide the result by the natural logarithm of the desired base.
References
[1]Differential entropy, Wikipedia, https://en.wikipedia.org/wiki/Differential_entropy
Examples
Instantiate a distribution with the desired parameters:
>>> from scipy import stats >>> X = stats.Uniform(a=-1., b=1.)
Evaluate the entropy:
>>> X.entropy() 0.6931471805599454