Returns the entropy of a degenerate distribution.
constant value of distribution
entropy
var v = entropy( 0.1 ); // returns 0.0
var v = entropy( 0.5 ); // returns 0.0
var v = entropy( 10.0 ); // returns 0.0
var v = entropy( NaN ); // returns NaN
Returns the entropy of a degenerate distribution.