time-to-botec/squiggle/node_modules/@stdlib/blas/base/dasum/lib/ndarray.js

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/**
* @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 {integer} stride - `x` stride length
* @param {NonNegativeInteger} offset - starting `x` index
* @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, 0 );
* // returns 15.0
*/
function dasum( N, x, stride, offset ) {
var sum;
var ix;
var m;
var i;
sum = 0.0;
if ( N <= 0 ) {
return sum;
}
ix = offset;
// 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[ix] );
ix += stride;
}
}
if ( N < M ) {
return sum;
}
for ( i = m; i < N; i += M ) {
sum += abs( x[ix] ) + abs( x[ix+1] ) + abs( x[ix+2] ) + abs( x[ix+3] ) + abs( x[ix+4] ) + abs( x[ix+5] ); // eslint-disable-line max-len
ix += M;
}
return sum;
}
for ( i = 0; i < N; i++ ) {
sum += abs( x[ix] );
ix += stride;
}
return sum;
}
// EXPORTS //
module.exports = dasum;