sswap.js (2346B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2020 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 // VARIABLES // 22 23 var M = 3; 24 25 26 // MAIN // 27 28 /** 29 * Interchanges two single-precision floating-point vectors. 30 * 31 * @param {PositiveInteger} N - number of values to swap 32 * @param {Float32Array} x - first input array 33 * @param {integer} strideX - `x` stride length 34 * @param {Float32Array} y - second input array 35 * @param {integer} strideY - `y` stride length 36 * @returns {Float32Array} `y` 37 * 38 * @example 39 * var Float32Array = require( '@stdlib/array/float32' ); 40 * 41 * var x = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] ); 42 * var y = new Float32Array( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] ); 43 * 44 * sswap( x.length, x, 1, y, 1 ); 45 * // x => <Float32Array>[ 6.0, 7.0, 8.0, 9.0, 10.0 ] 46 * // y => <Float32Array>[ 1.0, 2.0, 3.0, 4.0, 5.0 ] 47 */ 48 function sswap( N, x, strideX, y, strideY ) { 49 var tmp; 50 var ix; 51 var iy; 52 var m; 53 var i; 54 var j; 55 if ( N <= 0 ) { 56 return y; 57 } 58 // Use unrolled loops if both strides are equal to `1`... 59 if ( strideX === 1 && strideY === 1 ) { 60 m = N % M; 61 62 // If we have a remainder, run a clean-up loop... 63 if ( m > 0 ) { 64 for ( i = 0; i < m; i++ ) { 65 tmp = x[ i ]; 66 x[ i ] = y[ i ]; 67 y[ i ] = tmp; 68 } 69 } 70 if ( N < M ) { 71 return y; 72 } 73 for ( i = m; i < N; i += M ) { 74 tmp = x[ i ]; 75 x[ i ] = y[ i ]; 76 y[ i ] = tmp; 77 78 j = i + 1; 79 tmp = x[ j ]; 80 x[ j ] = y[ j ]; 81 y[ j ] = tmp; 82 83 j += 1; 84 tmp = x[ j ]; 85 x[ j ] = y[ j ]; 86 y[ j ] = tmp; 87 } 88 return y; 89 } 90 if ( strideX < 0 ) { 91 ix = (1-N) * strideX; 92 } else { 93 ix = 0; 94 } 95 if ( strideY < 0 ) { 96 iy = (1-N) * strideY; 97 } else { 98 iy = 0; 99 } 100 for ( i = 0; i < N; i++ ) { 101 tmp = x[ ix ]; 102 x[ ix ] = y[ iy ]; 103 y[ iy ] = tmp; 104 ix += strideX; 105 iy += strideY; 106 } 107 return y; 108 } 109 110 111 // EXPORTS // 112 113 module.exports = sswap;