log1pexp

Evaluates the natural logarithm of 1+exp(x).

Usage

var log1pexp = require( '@stdlib/math/base/special/log1pexp' );

log1pexp( x )

Evaluates the natural logarithm of 1+exp(x).

var y = log1pexp( -10.0 );
// returns ~0.000045

y = log1pexp( 0.0 );
// returns ~0.693147

y = log1pexp( 5.0 );
// returns ~5.006715

y = log1pexp( 34.0 );
// returns 34.0

y = log1pexp( NaN );
// returns NaN

Examples

var incrspace = require( '@stdlib/array/base/incrspace' );
var log1pexp = require( '@stdlib/math/base/special/log1pexp' );

var x = incrspace( -10.0, 10.0, 0.01 );

var i;
for ( i = 0; i < x.length; i++ ) {
    console.log( 'x: %d, f(x): %d', x[ i ], log1pexp( x[ i ] ) );
}