ndarray.native.js (2337B)
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 Float64Array = require( '@stdlib/array/float64' ); 24 var addon = require( './dmeanvar.native.js' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the mean and variance of a double-precision floating-point strided array. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {number} correction - degrees of freedom adjustment 34 * @param {Float64Array} x - input array 35 * @param {integer} strideX - `x` stride length 36 * @param {NonNegativeInteger} offsetX - `x` starting index 37 * @param {Float64Array} out - output array 38 * @param {integer} strideOut - `out` stride length 39 * @param {NonNegativeInteger} offsetOut - `out` starting index 40 * @returns {Float64Array} output array 41 * 42 * @example 43 * var Float64Array = require( '@stdlib/array/float64' ); 44 * var floor = require( '@stdlib/math/base/special/floor' ); 45 * 46 * var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] ); 47 * var out = new Float64Array( 2 ); 48 * 49 * var N = floor( x.length / 2 ); 50 * 51 * var v = dmeanvar( N, 1, x, 2, 1, out, 1, 0 ); 52 * // returns <Float64Array>[ 1.25, 6.25 ] 53 */ 54 function dmeanvar( N, correction, x, strideX, offsetX, out, strideOut, offsetOut ) { // eslint-disable-line max-len 55 var viewOut; 56 var viewX; 57 if ( strideX < 0 ) { 58 offsetX += (N-1) * strideX; 59 } 60 if ( strideOut < 0 ) { 61 offsetOut += strideOut; 62 } 63 viewX = new Float64Array( x.buffer, x.byteOffset+(x.BYTES_PER_ELEMENT*offsetX), x.length-offsetX ); // eslint-disable-line max-len 64 viewOut = new Float64Array( out.buffer, out.byteOffset+(out.BYTES_PER_ELEMENT*offsetOut), out.length-offsetOut ); // eslint-disable-line max-len 65 addon( N, correction, viewX, strideX, viewOut, strideOut ); 66 return out; 67 } 68 69 70 // EXPORTS // 71 72 module.exports = dmeanvar;