erfinv
The inverse error function is defined in terms of the Maclaurin series
where c_0 = 1
and
Usage
var erfinv = require( '@stdlib/math/base/special/erfinv' );
erfinv( x )
Evaluates the inverse error function.
var y = erfinv( 0.5 );
// returns ~0.4769
y = erfinv( 0.8 );
// returns ~0.9062
y = erfinv( -1.0 );
// returns -Infinity
y = erfinv( 1.0 );
// returns Infinity
The domain of x
is restricted to [-1,1]
. If |x| > 1
, the function returns NaN
.
var y = erfinv( -3.14 );
// returns NaN
If provided NaN
, the function returns NaN
.
var y = erfinv( NaN );
// returns NaN
The inverse error function is an odd function; i.e., erfinv(-x) = -erfinv(x)
. Thus, in accordance with the IEEE 754 standard, if provided -0
, the function returns -0
.
var y = erfinv( -0.0 );
// returns -0.0
Examples
var linspace = require( '@stdlib/array/base/linspace' );
var erfinv = require( '@stdlib/math/base/special/erfinv' );
var x = linspace( -1.0, 1.0, 100 );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( 'x: %d, erfinv(x): %d', x[ i ], erfinv( x[ i ] ) );
}
C APIs
Usage
#include "stdlib/math/base/special/erfinv.h"
stdlib_base_erfinv( x )
Evaluates the inverse error function.
double out = stdlib_base_erfinv( 0.5 );
// returns ~0.4769
out = stdlib_base_erfinv( 0.8 );
// returns ~0.9062
The function accepts the following arguments:
- x:
[in] double
input value.
double stdlib_base_erfinv( const double x );
Examples
#include "stdlib/math/base/special/erfinv.h"
#include <stdlib.h>
#include <stdio.h>
int main() {
const double x[] = { -1.0, -0.78, -0.56, -0.33, -0.11, 0.11, 0.33, 0.56, 0.78, 1.0 };
double v;
int i;
for ( i = 0; i < 10; i++ ) {
v = stdlib_base_erfinv( x[ i ] );
printf( "x: %lf, erfinv(x): %lf\n", x[ i ], v );
}
}