expm1

Compute exp(x) - 1.

Installation

npm install @stdlib/math-base-special-expm1

Usage

var expm1 = require( '@stdlib/math-base-special-expm1' );

expm1( x )

Computes exp(x) - 1, where exp(x) is the natural exponential function.

var v = expm1( 0.2 );
// returns ~0.221

v = expm1( -9.0 );
// returns ~-1.0

v = expm1( 0.0 );
// returns 0.0

v = expm1( NaN );
// returns NaN

Examples

var randu = require( '@stdlib/random-base-randu' );
var expm1 = require( '@stdlib/math-base-special-expm1' );

var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = (randu()*10.0) - 5.0;
    console.log( 'e^%d - 1 = %d', x, expm1( x ) );
}

C APIs

Usage

#include "stdlib/math/base/special/expm1.h"

stdlib_base_expm1( x )

Computes exp(x) - 1, where exp(x) is the natural exponential function.

double out = stdlib_base_expm1( 0.2 );
// returns ~0.221

out = stdlib_base_expm1( -9.0 );
// returns ~-1.0

The function accepts the following arguments:

• x: [in] double input value.

double stdlib_base_expm1( const double x );

Examples

#include "stdlib/math/base/special/expm1.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 ) * 10.0 ) - 5.0;
        v = stdlib_base_expm1( x );
        printf( "e^%lf - 1 = %lf\n", x, v );
    }
}

See Also

• @stdlib/math-base/special/exp: natural exponential function.
• @stdlib/math-base/special/expm1rel: relative error exponential.

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

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