sincospi

Simultaneously compute the sine and cosine of a number times π.

Usage

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

sincospi( x )

Simultaneously computes the sine and cosine of a number times π more accurately than sincos(pi*x), especially for large x.

var v = sincospi( 0.0 );
// returns [ 0.0, 1.0 ]

v = sincospi( 0.5 );
// returns [ 1.0, 0.0 ]

v = sincospi( 0.1 );
// returns [ ~0.309, ~0.951 ]

v = sincospi( NaN );
// returns [ NaN, NaN ]

sincospi( x, out, stride, offset )

Simultaneously computes the sine and cosine of a number times π more accurately than sincos(pi*x), especially for large x, and assigns results to a provided output array.

var Float64Array = require( '@stdlib/array/float64' );

var out = new Float64Array( 2 );

var v = sincospi.assign( 0.0, out, 1, 0 );
// returns <Float64Array>[ 0.0, 1.0 ]

var bool = ( v === out );
// returns true

Examples

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

var x = linspace( 0.0, 2.0, 101 );

var i;
for ( i = 0; i < x.length; i++ ) {
    console.log( sincospi( x[ i ] ) );
}

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C APIs

Usage

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

stdlib_base_sincospi( x, &sine, &cosine )

Simultaneously computes the sine and cosine of a number times π more accurately than sincos(pi*x), especially for large x.

double cosine;
double sine;

stdlib_base_sincospi( 4.0, &sine, &cosine );

The function accepts the following arguments:

• x: [in] double input value.
• sine: [out] double* destination for the sine.
• cosine: [out] double* destination for the cosine.

void stdlib_base_sincospi( const double x, double *sine, double *cosine );

Examples

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

int main( void ) {
    const double x[] = { 0.0, 1.57, 3.14, 6.28 };

    double cosine;
    double sine;
    int i;
    for ( i = 0; i < 4; i++ ) {
        stdlib_base_sincospi( x[ i ], &sine, &cosine );
        printf( "x: %lf => sine: %lf, cosine: %lf\n", x[ i ], sine, cosine );
    }
}

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See Also

• @stdlib/math/base/special/cospi: compute cos(πx).
• @stdlib/math/base/special/sincos: simultaneously compute the sine and cosine of an angle measured in radians.
• @stdlib/math/base/special/sinpi: compute sin(πx).