time-to-botec

Benchmark sampling in different programming languages
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sincospi.js (2581B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2018 The Stdlib Authors.
      5 *
      6 * Licensed under the Apache License, Version 2.0 (the "License");
      7 * you may not use this file except in compliance with the License.
      8 * You may obtain a copy of the License at
      9 *
     10 *    http://www.apache.org/licenses/LICENSE-2.0
     11 *
     12 * Unless required by applicable law or agreed to in writing, software
     13 * distributed under the License is distributed on an "AS IS" BASIS,
     14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15 * See the License for the specific language governing permissions and
     16 * limitations under the License.
     17 */
     18 
     19 'use strict';
     20 
     21 // MODULES //
     22 
     23 var isnan = require( './../../../../base/assert/is-nan' );
     24 var isInfinite = require( './../../../../base/assert/is-infinite' );
     25 var abs = require( './../../../../base/special/abs' );
     26 var sincos = require( './../../../../base/special/sincos' );
     27 var floor = require( './../../../../base/special/floor' );
     28 var PI = require( '@stdlib/constants/float64/pi' );
     29 var copysign = require( './../../../../base/special/copysign' );
     30 
     31 
     32 // MAIN //
     33 
     34 /**
     35 * Simultaneously computes the sine and cosine of a number times π.
     36 *
     37 * @private
     38 * @param {(Array|TypedArray|Object)} out - destination array
     39 * @param {number} x - input value
     40 * @returns {(Array|TypedArray|Object)} two-element array containing sin(πx) and cos(πx)
     41 *
     42 * @example
     43 * var v = sincospi( [ 0.0, 0.0 ], 0.0 );
     44 * // returns [ 0.0, 1.0 ]
     45 *
     46 * @example
     47 * var v = sincospi( [ 0.0, 0.0 ], 0.5 );
     48 * // returns [ 1.0, 0.0 ]
     49 *
     50 * @example
     51 * var v = sincospi( [ 0.0, 0.0 ], 0.1 );
     52 * // returns [ ~0.309, ~0.951 ]
     53 *
     54 * @example
     55 * var v = sincospi( [ 0.0, 0.0 ], NaN );
     56 * // returns [ NaN, NaN ]
     57 */
     58 function sincospi( out, x ) {
     59 	var tmp;
     60 	var ix;
     61 	var ar;
     62 	var r;
     63 
     64 	if ( isnan( x ) || isInfinite( x ) ) {
     65 		out[ 0 ] = NaN;
     66 		out[ 1 ] = NaN;
     67 		return out;
     68 	}
     69 	r = x % 2.0;
     70 	ar = abs( r );
     71 	if ( ar === 0.0 || ar === 1.0 ) {
     72 		ix = floor( ar );
     73 		out[ 0 ] = copysign( 0.0, r );
     74 		out[ 1 ] = ( ix%2 === 1 ) ? -1.0 : 1.0;
     75 		return out;
     76 	}
     77 	if ( ar < 0.25 ) {
     78 		return sincos( out, PI*r );
     79 	}
     80 	if ( ar < 0.75 ) {
     81 		ar = 0.5 - ar;
     82 		sincos( out, PI*ar );
     83 		tmp = out[ 0 ];
     84 		out[ 0 ] = copysign( out[ 1 ], r );
     85 		out[ 1 ] = tmp;
     86 		return out;
     87 	}
     88 	if ( ar < 1.25 ) {
     89 		r = copysign( 1.0, r ) - r;
     90 		sincos( out, PI*r );
     91 		out[ 1 ] *= -1;
     92 		return out;
     93 	}
     94 	if ( ar < 1.75 ) {
     95 		ar -= 1.5;
     96 		sincos( out, PI*ar );
     97 		tmp = out[ 0 ];
     98 		out[ 0 ] = -copysign( out[ 1 ], r );
     99 		out[ 1 ] = tmp;
    100 		return out;
    101 	}
    102 	r -= copysign( 2.0, r );
    103 	return sincos( out, PI*r );
    104 }
    105 
    106 
    107 // EXPORTS //
    108 
    109 module.exports = sincospi;