binaryEntropy

inline double binaryEntropy(const double p) noexcept: Calculates the discrete binary entropy [1] of a probability.

Parameters

const double p

A real number between 0 and 1 inclusive.

Returns

double

A real number.

The binary entropy of a probability \(p\) is defined as follows:

\[\DeclareMathOperator\H{H} H(X) = -p\log(p) + (1 - p)\log(1 - p)\]

Example

std::cout << binaryEntropy(0.5) << "\n";

Output:

0.693147

References