sdsmeanors.js (1650B)
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 // MODULES // 22 23 var float64ToFloat32 = require( '@stdlib/number/float64/base/to-float32' ); 24 25 26 // MAIN // 27 28 /** 29 * Computes the arithmetic mean of a single-precision floating-point strided array using ordinary recursive summation with extended accumulation. 30 * 31 * @param {PositiveInteger} N - number of indexed elements 32 * @param {Float32Array} x - input array 33 * @param {integer} stride - stride length 34 * @returns {number} arithmetic mean 35 * 36 * @example 37 * var Float32Array = require( '@stdlib/array/float32' ); 38 * 39 * var x = new Float32Array( [ 1.0, -2.0, 2.0 ] ); 40 * var N = x.length; 41 * 42 * var v = sdsmeanors( N, x, 1 ); 43 * // returns ~0.3333 44 */ 45 function sdsmeanors( N, x, stride ) { 46 var sum; 47 var ix; 48 var i; 49 50 if ( N <= 0 ) { 51 return NaN; 52 } 53 if ( N === 1 || stride === 0 ) { 54 return x[ 0 ]; 55 } 56 if ( stride < 0 ) { 57 ix = (1-N) * stride; 58 } else { 59 ix = 0; 60 } 61 sum = 0.0; 62 for ( i = 0; i < N; i++ ) { 63 sum += x[ ix ]; 64 ix += stride; 65 } 66 return float64ToFloat32( sum / N ); 67 } 68 69 70 // EXPORTS // 71 72 module.exports = sdsmeanors;