62 lines
1.5 KiB
C
62 lines
1.5 KiB
C
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/**
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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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#include "stdlib/blas/base/dasum.h"
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#include <math.h>
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/**
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* Computes the sum of absolute values.
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*
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* @param N number of elements to sum
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* @param X input array
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* @param stride stride length
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* @return sum of absolute values
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*/
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double c_dasum( const int N, const double *X, const int stride ) {
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double sum;
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int m;
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int i;
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sum = 0.0;
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if ( N <= 0 || stride <= 0 ) {
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return sum;
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}
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// If the stride is equal to `1`, use unrolled loops...
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if ( stride == 1 ) {
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m = N % 6;
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// If we have a remainder, run a clean-up loop...
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if ( m > 0 ) {
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for ( i = 0; i < m; i++ ) {
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sum += fabs( X[i] );
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}
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}
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if ( N < 6 ) {
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return sum;
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}
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for ( i = m; i < N; i += 6 ) {
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sum += fabs( X[i] ) + fabs( X[i+1] ) + fabs( X[i+2] ) + fabs( X[i+3] ) + fabs( X[i+4] ) + fabs( X[i+5] );
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}
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return sum;
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}
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for ( i = 0; i < N*stride; i += stride ) {
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sum += fabs( X[i] );
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}
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return sum;
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}
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