Skip to content

README.md

Latest commit

 

History

History
254 lines (156 loc) · 7.16 KB

README.md

File metadata and controls

254 lines (156 loc) · 7.16 KB

boxcoxf

Compute a one-parameter Box-Cox transformation for single-precision floating-point number.

The one-parameter Box-Cox transformation is defined as

One-Parameter Box-Cox Transformation

Usage

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

boxcoxf( x, lambda )

Computes a one-parameter Box-Cox transformation for a single-precision floating-point number.

var v = boxcoxf( 1.0, 2.5 );
// returns 0.0

v = boxcoxf( 4.0, 2.5 );
// returns ~12.4

v = boxcoxf( 10.0, 2.5 );
// returns ~126.0911

v = boxcoxf( 2.0, 0.0 );
// returns ~0.6931

v = boxcoxf( -1.0, 2.5 );
// returns NaN

v = boxcoxf( 0.0, -1.0 );
// returns -Infinity

Examples

var incrspace = require( '@stdlib/array/base/incrspace' );
var boxcoxf = require( '@stdlib/math/base/special/boxcoxf' );

var x = incrspace( -1.0, 10.0, 1.0 );
var l = incrspace( -0.5, 5.0, 0.5 );

var b;
var i;
var j;
for ( i = 0; i < x.length; i++ ) {
    for ( j = 0; j < l.length; j++ ) {
        b = boxcoxf( x[ i ], l[ j ] );
        console.log( 'boxcoxf(%d, %d) = %d', x[ i ], l[ j ], b );
    }
}

C APIs

Usage

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

stdlib_base_boxcoxf( x, lambda )

Computes a one-parameter Box-Cox transformation for a single-precision floating-point number.

float out = stdlib_base_boxcoxf( 1.0f, 2.5f );
// returns 0.0f

out = stdlib_base_boxcoxf( 4.0f, 2.5f );
// returns ~12.4f

The function accepts the following arguments:

  • x: [in] float input value.
  • lambda: [in] float power parameter.
float stdlib_base_boxcoxf( const float x, const float lambda );

Examples

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

int main( void ) {
    const float x[] = { -1.0f, 10.0f, 1.0f };
    const float y[] = { -0.5f, 5.0f, 0.5f };

    float out;
    int i;
    int j;
    for ( i = 0; i < 3; i++ ) {
        for ( j = 0; j < 3; j++ ) {
            out = stdlib_base_boxcoxf( x[ i ], y[ j ] );
            printf( "x: %f, y: %f, out: %f\n", x[ i ], y[ j ], out );
        }
    }
}

References

  • Box, G. E. P., and D. R. Cox. 1964. "An Analysis of Transformations." Journal of the Royal Statistical Society. Series B (Methodological) 26 (2). [Royal Statistical Society, Wiley]: 211–52. http://www.jstor.org/stable/2984418.

See Also