73 lines
2.3 KiB
JavaScript
73 lines
2.3 KiB
JavaScript
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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2020 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var Float64Array = require( '@stdlib/array/float64' );
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var addon = require( './dmeanvar.native.js' );
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// MAIN //
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/**
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* Computes the mean and variance of a double-precision floating-point strided array.
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*
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* @param {PositiveInteger} N - number of indexed elements
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* @param {number} correction - degrees of freedom adjustment
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* @param {Float64Array} x - input array
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* @param {integer} strideX - `x` stride length
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* @param {NonNegativeInteger} offsetX - `x` starting index
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* @param {Float64Array} out - output array
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* @param {integer} strideOut - `out` stride length
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* @param {NonNegativeInteger} offsetOut - `out` starting index
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* @returns {Float64Array} output array
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*
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* @example
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* var Float64Array = require( '@stdlib/array/float64' );
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* var floor = require( '@stdlib/math/base/special/floor' );
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*
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* var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
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* var out = new Float64Array( 2 );
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*
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* var N = floor( x.length / 2 );
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*
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* var v = dmeanvar( N, 1, x, 2, 1, out, 1, 0 );
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* // returns <Float64Array>[ 1.25, 6.25 ]
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*/
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function dmeanvar( N, correction, x, strideX, offsetX, out, strideOut, offsetOut ) { // eslint-disable-line max-len
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var viewOut;
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var viewX;
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if ( strideX < 0 ) {
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offsetX += (N-1) * strideX;
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}
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if ( strideOut < 0 ) {
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offsetOut += strideOut;
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}
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viewX = new Float64Array( x.buffer, x.byteOffset+(x.BYTES_PER_ELEMENT*offsetX), x.length-offsetX ); // eslint-disable-line max-len
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viewOut = new Float64Array( out.buffer, out.byteOffset+(out.BYTES_PER_ELEMENT*offsetOut), out.length-offsetOut ); // eslint-disable-line max-len
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addon( N, correction, viewX, strideX, viewOut, strideOut );
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return out;
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}
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// EXPORTS //
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module.exports = dmeanvar;
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