80 lines
1.7 KiB
JavaScript
80 lines
1.7 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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// MAIN //
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/**
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* Computes the sum along a matrix dimension.
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*
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* @param {Matrix} mat - input matrix
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* @param {number} [dim=2] - matrix dimension along which to compute the sum. If `dim=1`, compute along matrix rows. If `dim=2`, compute along matrix columns.
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* @returns {(Int32Array|number)} sums or 0
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*/
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function sum( mat, dim ) {
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var out;
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var s0;
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var s1;
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var s;
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var M;
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var N;
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var o;
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var i;
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var j;
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var k;
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if ( dim === 1 ) {
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// Compute along the rows...
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M = mat.shape[ 1 ];
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N = mat.shape[ 0 ];
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s0 = mat.strides[ 1 ];
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s1 = mat.strides[ 0 ];
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} else {
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// Compute along the columns...
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M = mat.shape[ 0 ];
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N = mat.shape[ 1 ];
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s0 = mat.strides[ 0 ];
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s1 = mat.strides[ 1 ];
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}
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if ( M === 0 || N === 0 ) {
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return 0;
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}
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out = new Float64Array( M );
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o = mat.offset;
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for ( i = 0; i < M; i++ ) {
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k = o + ( i*s0 );
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s = 0;
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for ( j = 0; j < N; j++ ) {
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s += mat.data[ k + ( j*s1 ) ];
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}
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out[ i ] = s;
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}
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return out;
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}
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// EXPORTS //
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module.exports = sum;
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