sfill.js (1998B)
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 = 8; 24 25 26 // MAIN // 27 28 /** 29 * Fills a single-precision floating-point strided array with a specified scalar constant. 30 * 31 * @param {PositiveInteger} N - number of indexed elements 32 * @param {number} alpha - scalar 33 * @param {Float32Array} x - input array 34 * @param {integer} stride - index increment 35 * @returns {Float32Array} input array 36 * 37 * @example 38 * var Float32Array = require( '@stdlib/array/float32' ); 39 * 40 * var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] ); 41 * 42 * sfill( x.length, 5.0, x, 1 ); 43 * // x => <Float32Array>[ 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0 ] 44 */ 45 function sfill( N, alpha, x, stride ) { 46 var ix; 47 var i; 48 var m; 49 50 if ( N <= 0 ) { 51 return x; 52 } 53 // Use loop unrolling if the stride is equal to `1`... 54 if ( stride === 1 ) { 55 m = N % M; 56 57 // If we have a remainder, run a clean-up loop... 58 if ( m > 0 ) { 59 for ( i = 0; i < m; i++ ) { 60 x[ i ] = alpha; 61 } 62 } 63 if ( N < M ) { 64 return x; 65 } 66 for ( i = m; i < N; i += M ) { 67 x[ i ] = alpha; 68 x[ i+1 ] = alpha; 69 x[ i+2 ] = alpha; 70 x[ i+3 ] = alpha; 71 x[ i+4 ] = alpha; 72 x[ i+5 ] = alpha; 73 x[ i+6 ] = alpha; 74 x[ i+7 ] = alpha; 75 } 76 return x; 77 } 78 if ( stride < 0 ) { 79 ix = (1-N) * stride; 80 } else { 81 ix = 0; 82 } 83 for ( i = 0; i < N; i++ ) { 84 x[ ix ] = alpha; 85 ix += stride; 86 } 87 return x; 88 } 89 90 91 // EXPORTS // 92 93 module.exports = sfill;