erf

Error function.

The error function is defined as

Usage

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

erf( x )

Evaluates the error function.

var y = erf( 2.0 );
// returns ~0.9953

y = erf( -1.0 );
// returns ~-0.8427

If provided NaN, the function returns NaN.

var y = erf( NaN );
// returns NaN

The error function is an odd function; i.e., erf(-x) = -erf(x). Thus, in accordance with the IEEE 754 standard, if provided -0, the function returns -0.

var y = erf( -0.0 );
// returns -0.0

Examples

var linspace = require( '@stdlib/array/base/linspace' );
var erf = require( '@stdlib/math/base/special/erf' );

var x = linspace( -10.0, 10.0, 100 );

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

C APIs

Usage

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

stdlib_base_erf( x )

Evaluates the error function.

double out = stdlib_base_erf( 2.0 );
// returns ~0.9953

out = stdlib_base_erf( -1.0 );
// returns ~-0.8427

The function accepts the following arguments:

x: [in] double input value.

double stdlib_base_erf( const double x );

Examples

#include "stdlib/math/base/special/erf.h"
#include <stdio.h>

int main( void ) {
    const double x[] = { -10.0, -7.78, -5.56, -3.33, -1.11, 1.11, 3.33, 5.56, 7.78, 10.0 };
    
    double v;
    int i;
    for ( i = 0; i < 10; i++ ) {
        v = stdlib_base_erf( x[ i ] );
        printf( "x: %lf, erf(x): %lf\n", x[ i ], v );
    }
}