65 lines
1.6 KiB
JavaScript
65 lines
1.6 KiB
JavaScript
|
/**
|
|||
|
|
* @license Apache-2.0
|
|||
|
|
*
|
|||
|
|
* Copyright (c) 2020 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 gsumkbn2 = require( '@stdlib/blas/ext/base/gsumkbn2' );
|
|||
|
|
|
|||
|
|
|
|||
|
|
// MAIN //
|
|||
|
|
|
|||
|
|
/**
|
|||
|
|
* Computes the arithmetic mean of a strided array using a second-order iterative Kahan–Babuška algorithm.
|
|||
|
|
*
|
|||
|
|
* ## Method
|
|||
|
|
*
|
|||
|
|
* - This implementation uses a second-order iterative Kahan–Babuška algorithm, as described by Klein (2005).
|
|||
|
|
*
|
|||
|
|
* ## References
|
|||
|
|
*
|
|||
|
|
* - Klein, Andreas. 2005. "A Generalized Kahan-Babuška-Summation-Algorithm." _Computing_ 76 (3): 279–93. doi:[10.1007/s00607-005-0139-x](https://doi.org/10.1007/s00607-005-0139-x).
|
|||
|
|
*
|
|||
|
|
* @param {PositiveInteger} N - number of indexed elements
|
|||
|
|
* @param {NumericArray} x - input array
|
|||
|
|
* @param {integer} stride - stride length
|
|||
|
|
* @returns {number} arithmetic mean
|
|||
|
|
*
|
|||
|
|
* @example
|
|||
|
|
* var x = [ 1.0, -2.0, 2.0 ];
|
|||
|
|
* var N = x.length;
|
|||
|
|
*
|
|||
|
|
* var v = meankbn2( N, x, 1 );
|
|||
|
|
* // returns ~0.3333
|
|||
|
|
*/
|
|||
|
|
function meankbn2( N, x, stride ) {
|
|||
|
|
if ( N <= 0 ) {
|
|||
|
|
return NaN;
|
|||
|
|
}
|
|||
|
|
if ( N === 1 || stride === 0 ) {
|
|||
|
|
return x[ 0 ];
|
|||
|
|
}
|
|||
|
|
return gsumkbn2( N, x, stride ) / N;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
// EXPORTS //
|
|||
|
|
|
|||
|
|
module.exports = meankbn2;
|