74 lines
1.6 KiB
JavaScript
74 lines
1.6 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' );
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns an accumulator function which incrementally computes a sum of absolute values.
|
||
|
|
*
|
||
|
|
* @returns {Function} accumulator function
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var accumulator = incrsumabs();
|
||
|
|
*
|
||
|
|
* var sum = accumulator();
|
||
|
|
* // returns null
|
||
|
|
*
|
||
|
|
* sum = accumulator( 2.0 );
|
||
|
|
* // returns 2.0
|
||
|
|
*
|
||
|
|
* sum = accumulator( -5.0 );
|
||
|
|
* // returns 7.0
|
||
|
|
*
|
||
|
|
* sum = accumulator();
|
||
|
|
* // returns 7.0
|
||
|
|
*/
|
||
|
|
function incrsumabs() {
|
||
|
|
var sum = 0.0;
|
||
|
|
var FLG;
|
||
|
|
return accumulator;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* If provided a value, the accumulator function returns an updated sum. If not provided a value, the accumulator function returns the current sum.
|
||
|
|
*
|
||
|
|
* @private
|
||
|
|
* @param {number} [x] - new value
|
||
|
|
* @returns {(number|null)} sum or null
|
||
|
|
*/
|
||
|
|
function accumulator( x ) {
|
||
|
|
if ( arguments.length === 0 ) {
|
||
|
|
return ( FLG ) ? sum : null;
|
||
|
|
}
|
||
|
|
FLG = true;
|
||
|
|
sum += abs( x );
|
||
|
|
return sum;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = incrsumabs;
|