rempio2f

Compute x - nπ/2 = r (single-precision).

Installation

npm install @stdlib/math-base-special-rempio2f

Usage

var rempio2f = require( '@stdlib/math-base-special-rempio2f' );

rempio2f( x, y )

Computes x - nπ/2 = r.

var y = [ 0.0 ];
var n = rempio2f( 128.0, y );
// returns 81

var y1 = y[ 0 ];
// returns ~0.765

When x is NaN or infinite, the function returns 0 and sets y[0] to NaN.

var y = [ 0.0 ];
var n = rempio2f( NaN, y );
// returns 0

var y1 = y[ 0 ];
// returns NaN

y = [ 0.0 ];
n = rempio2f( Infinity, y );
// returns 0

y1 = y[ 0 ];
// returns NaN

Notes

• The function returns n and stores the remainder r as y[0].
• For input values larger than 2^28*π/2 in magnitude, the function only returns the last three binary digits of n and not the full result.

Examples

var linspace = require( '@stdlib/array-base-linspace' );
var rempio2f = require( '@stdlib/math-base-special-rempio2f' );

var x = linspace( 0.0, 100.0, 100 );
var y = [ 0.0 ];
var n;
var i;

for ( i = 0; i < x.length; i++ ) {
    n = rempio2f( x[ i ], y );
    console.log( '%d - %dπ/2 = %d', x[ i ], n, y[ 0 ] );
}

C APIs

Usage

#include "stdlib/math/base/special/rempio2f.h"

stdlib_base_rempio2f( x, &rem )

Computes x - nπ/2 = r (single-precision).

#include <stdint.h>

double rem;

int32_t n = stdlib_base_rempio2f( 4.0f, &rem );

The function accepts the following arguments:

• x: [in] float input value.
• rem: [out] double* destination for the remainder.

int32_t stdlib_base_rempio2f( const float x, double *rem );

Examples

#include "stdlib/math/base/special/rempio2f.h"
#include <stdio.h>
#include <stdint.h>
#include <inttypes.h>

int main( void ) {
    const float x[] = { 0.0f, 1.0f, 4.0f, 128.0f };

    double rem;
    int32_t n;
    int i;
    for ( i = 0; i < 4; i++ ) {
        n = stdlib_base_rempio2f( x[ i ], &rem );
        printf( "%f - %"PRId32"π/2 = %lf\n", x[ i ], n, rem );
    }
}

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 © 2016-2026. The Stdlib Authors.