87 lines
1.8 KiB
JavaScript
87 lines
1.8 KiB
JavaScript
/**
|
|
* @license Apache-2.0
|
|
*
|
|
* Copyright (c) 2018 The Stdlib Authors.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
'use strict';
|
|
|
|
// MODULES //
|
|
|
|
var abs = require( '@stdlib/math/base/special/abs' );
|
|
|
|
|
|
// VARIABLES //
|
|
|
|
var M = 6;
|
|
|
|
|
|
// MAIN //
|
|
|
|
/**
|
|
* Computes the sum of absolute values.
|
|
*
|
|
* @param {PositiveInteger} N - number of values to sum
|
|
* @param {Float64Array} x - input array
|
|
* @param {PositiveInteger} stride - `x` stride length
|
|
* @returns {number} sum
|
|
*
|
|
* @example
|
|
* var Float64Array = require( '@stdlib/array/float64' );
|
|
*
|
|
* var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0 ] );
|
|
*
|
|
* var s = dasum( x.length, x, 1 );
|
|
* // returns 15.0
|
|
*/
|
|
function dasum( N, x, stride ) {
|
|
var sum;
|
|
var m;
|
|
var i;
|
|
|
|
sum = 0.0;
|
|
if ( N <= 0 || stride <= 0 ) {
|
|
return sum;
|
|
}
|
|
// Use unrolled loops if the stride is equal to `1`...
|
|
if ( stride === 1 ) {
|
|
m = N % M;
|
|
|
|
// If we have a remainder, run a clean-up loop...
|
|
if ( m > 0 ) {
|
|
for ( i = 0; i < m; i++ ) {
|
|
sum += abs( x[i] );
|
|
}
|
|
}
|
|
if ( N < M ) {
|
|
return sum;
|
|
}
|
|
for ( i = m; i < N; i += M ) {
|
|
sum += abs(x[i]) + abs(x[i+1]) + abs(x[i+2]) + abs(x[i+3]) + abs(x[i+4]) + abs(x[i+5]); // eslint-disable-line max-len
|
|
}
|
|
return sum;
|
|
}
|
|
N *= stride;
|
|
for ( i = 0; i < N; i += stride ) {
|
|
sum += abs( x[i] );
|
|
}
|
|
return sum;
|
|
}
|
|
|
|
|
|
// EXPORTS //
|
|
|
|
module.exports = dasum;
|