rempio2

Compute x - nπ/2 = r.

Usage

var rempio2 = require( '@stdlib/math/base/special/rempio2' );

rempio2( x, y )

Computes x - nπ/2 = r. The function returns n and stores the remainder r as two numbers in y, such that y[0]+y[1] = r.

var y = new Array( 2 );
var n = rempio2( 128.0, y );
// returns 81

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

var y2 = y[ 1 ];
// returns ~3.618e-17

When x is NaN or infinite, the function returns zero and sets the elements of y to NaN.

var y = new Array( 2 );
var n = rempio2( NaN, y );
// returns 0

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

var y2 = y[ 1 ];
// returns NaN

y = new Array( 2 );
n = rempio2( Infinity, y );
// returns 0

y1 = y[ 0 ];
// returns NaN

y2 = y[ 1 ];
// returns NaN

Notes

  • For input values larger than 2^20*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/math/utils/linspace' );
var rempio2 = require( '@stdlib/math/base/special/rempio2' );

var x = linspace( 0.0, 100.0, 100 );
var y = new Array( 2 );
var n;
var i;

for ( i = 0; i < x.length; i++ ) {
    n = rempio2( x[ i ], y );
    console.log( '%d - %dπ/2 = %d + %d', x[ i ], n, y[ 0 ], y[ 1 ] );
}