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/**
* @license Apache-2.0
*
* Copyright (c) 2026 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 //
 
/**
* Computes the residual sum of squares of two double-precision floating-point strided arrays using an improved Kahan–Babuška algorithm.
*
* ## Method
*
* -   This implementation uses an "improved Kahan–Babuška algorithm", as described by Neumaier (1974).
*
* ## References
*
* -   Neumaier, Arnold. 1974. "Rounding Error Analysis of Some Methods for Summing Finite Sums." _Zeitschrift Für Angewandte Mathematik Und Mechanik_ 54 (1): 39–51. doi:[10.1002/zamm.19740540106](https://doi.org/10.1002/zamm.19740540106).
*
* @param {PositiveInteger} N - number of indexed elements
* @param {Float64Array} x - first input array
* @param {integer} strideX - stride length of `x`
* @param {NonNegativeInteger} offsetX - starting index of `x`
* @param {Float64Array} y - second input array
* @param {integer} strideY - stride length of `y`
* @param {NonNegativeInteger} offsetY - starting index of `y`
* @returns {number} residual sum of squares
*
* @example
* var Float64Array = require( '@stdlib/array/float64' );
*
* var x = new Float64Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0 ] );
* var y = new Float64Array( [ 2.0, 1.0, 2.0, 1.0, -2.0, 2.0, 3.0, 4.0 ] );
*
* var z = drsskbn( x.length, x, 1, 0, y, 1, 0 );
* // returns 72.0
*/
function drsskbn( N, x, strideX, offsetX, y, strideY, offsetY ) {
	var sum;
	var ix;
	var iy;
	var r;
	var v;
	var t;
	var c;
	var i;

	if ( N <= 0 ) {
		return 0.0;
	}
	ix = offsetX;
	iy = offsetY;
	sum = 0.0;
	c = 0.0;
	for ( i = 0; i < N; i++ ) {
		r = x[ ix ] - y[ iy ];
		v = r * r;
		t = sum + v;
		if ( abs( sum ) >= abs( v ) ) {
			c += ( sum - t ) + v;
		} else {
			c += ( v - t ) + sum;
		}
		sum = t;
		ix += strideX;
		iy += strideY;
	}
	return sum + c;
}
 
 
// EXPORTS //
 
module.exports = drsskbn;