71 lines
2.1 KiB
JavaScript
71 lines
2.1 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 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( './daxpy.native.js' );
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// MAIN //
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/**
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* Multiplies a vector `x` by a constant and adds the result to `y`.
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*
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* @param {PositiveInteger} N - number of elements
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* @param {number} alpha - scalar
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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 - starting `x` index
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* @param {Float64Array} y - destination array
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* @param {integer} strideY - `y` stride length
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* @param {NonNegativeInteger} offsetY - starting `y` index
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* @returns {Float64Array} `y`
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*
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* @example
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* var Float64Array = require( '@stdlib/array/float64' );
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*
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* var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
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* var y = new Float64Array( [ 1.0, 1.0, 1.0, 1.0, 1.0 ] );
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* var alpha = 5.0;
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*
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* daxpy( x.length, alpha, x, 1, 0, y, 1, 0 );
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* // y => <Float64Array>[ 6.0, 11.0, 16.0, 21.0, 26.0 ]
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*/
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function daxpy( N, alpha, x, strideX, offsetX, y, strideY, offsetY ) {
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var viewX;
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var viewY;
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if ( strideX < 0 ) {
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offsetX += (N-1) * strideX;
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}
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if ( strideY < 0 ) {
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offsetY += (N-1) * strideY;
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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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viewY = new Float64Array( y.buffer, y.byteOffset+(y.BYTES_PER_ELEMENT*offsetY), y.length-offsetY ); // eslint-disable-line max-len
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addon( N, alpha, viewX, strideX, viewY, strideY );
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return y;
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}
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// EXPORTS //
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module.exports = daxpy;
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