ndarray.js (1688B)
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 var ssumpw = require( '@stdlib/blas/ext/base/ssumpw' ).ndarray; 25 26 27 // MAIN // 28 29 /** 30 * Computes the arithmetic mean of a single-precision floating-point strided array using pairwise summation. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {Float32Array} x - input array 34 * @param {integer} stride - stride length 35 * @param {NonNegativeInteger} offset - starting index 36 * @returns {number} arithmetic mean 37 * 38 * @example 39 * var Float32Array = require( '@stdlib/array/float32' ); 40 * var floor = require( '@stdlib/math/base/special/floor' ); 41 * 42 * var x = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] ); 43 * var N = floor( x.length / 2 ); 44 * 45 * var v = smeanpw( N, x, 2, 1 ); 46 * // returns 1.25 47 */ 48 function smeanpw( N, x, stride, offset ) { 49 if ( N <= 0 ) { 50 return NaN; 51 } 52 if ( N === 1 || stride === 0 ) { 53 return x[ offset ]; 54 } 55 return float64ToFloat32( ssumpw( N, x, stride, offset ) / N ); 56 } 57 58 59 // EXPORTS // 60 61 module.exports = smeanpw;