@stdlib/math-base-special-log1pexp
v0.2.3
Published
Evaluate the natural logarithm of 1+exp(x).
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log1pexp
Evaluates the natural logarithm of
1+exp(x)
.
Installation
npm install @stdlib/math-base-special-log1pexp
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 ] ) );
}
C APIs
Usage
#include "stdlib/math/base/special/log1pexp.h"
stdlib_base_log1pexp( x )
Evaluates the natural logarithm of 1+exp(x)
.
double out = stdlib_base_log1pexp( 5.0 );
// returns ~5.006715
out = stdlib_base_log1pexp( 34.0 );
// returns 34.0
The function accepts the following arguments:
- x:
[in] double
input value.
double stdlib_base_log1pexp( const double x );
Examples
#include "stdlib/math/base/special/log1pexp.h"
#include <stdlib.h>
#include <stdio.h>
int main( void ) {
double x;
double v;
int i;
for ( i = 0; i < 100; i++ ) {
x = ( ( (double)rand() / (double)RAND_MAX ) * 20.0 ) - 10.0;
v = stdlib_base_log1pexp( x );
printf( "x: %lf, f(x): %lf\n", x, v );
}
}
See Also
@stdlib/math-base/special/exp
: natural exponential function.@stdlib/math-base/special/ln
: evaluate the natural logarithm of a double-precision floating-point number.@stdlib/math-base/special/log1mexp
: evaluate the natural logarithm of 1-exp(-|x|).@stdlib/math-base/special/log1p
: evaluate the natural logarithm of 1+x.
Notice
This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.