@stdlib/math-base-special-log1p
v0.2.3
Published
Evaluate the natural logarithm of 1+x.
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log1p
Evaluate the natural logarithm of
1+x
.
Installation
npm install @stdlib/math-base-special-log1p
Usage
var log1p = require( '@stdlib/math-base-special-log1p' );
log1p( x )
Evaluates the natural logarithm of 1+x
.
var v = log1p( 4.0 );
// returns ~1.609
v = log1p( -1.0 );
// returns -Infinity
v = log1p( Infinity );
// returns Infinity
v = log1p( 0.0 );
// returns 0.0
v = log1p( -0.0 );
// returns -0.0
v = log1p( NaN );
// returns NaN
For x < -1
, the function returns NaN
, as the natural logarithm is not defined for negative numbers.
var v = log1p( -2.0 );
// returns NaN
Examples
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var log1p = require( '@stdlib/math-base-special-log1p' );
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = round( randu() * 100.0 );
console.log( log1p( x ) );
}
C APIs
Usage
#include "stdlib/math/base/special/log1p.h"
stdlib_base_log1p( x )
Evaluates the natural logarithm of 1+x
.
double out = stdlib_base_log1p( 4.0 );
// returns ~1.609
out = stdlib_base_log1p( -1.0 );
// returns -Infinity
The function accepts the following arguments:
- x:
[in] double
input value.
double stdlib_base_log1p( const double x );
Examples
#include "stdlib/math/base/special/log1p.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 ) * 100.0;
v = stdlib_base_log1p( x );
printf( "log1p(%lf) = %lf\n", x, v );
}
}
See Also
@stdlib/math-base/special/ln
: evaluate the natural logarithm of a double-precision floating-point number.@stdlib/math-base/special/log
: baseb
logarithm.
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.
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Copyright
Copyright © 2016-2024. The Stdlib Authors.