text: /**
  * @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 float64ToFloat32 = require( '@stdlib/number-float64-base-to-float32' );
  var abs = require( '@stdlib/math-base-special-abs' );
  
  
  // MAIN //
  
  /**
  * Adds a constant to each single-precision floating-point strided array element and computes the sum 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 {number} alpha - constant
  * @param {Float32Array} x - input array
  * @param {integer} stride - stride length
  * @returns {number} sum
  *
  * @example
  * var Float32Array = require( '@stdlib/array-float32' );
  *
  * var x = new Float32Array( [ 1.0, -2.0, 2.0 ] );
  * var N = x.length;
  *
  * var v = sapxsumkbn( N, 5.0, x, 1 );
  * // returns 16.0
  */
  function sapxsumkbn( N, alpha, x, stride ) {
  	var sum;
  	var ix;
  	var v;
  	var t;
  	var c;
  	var i;
  
  	if ( N <= 0 ) {
  		return 0.0;
  	}
  	if ( N === 1 || stride === 0 ) {
  		return float64ToFloat32( alpha + x[ 0 ] );
  	}
  	if ( stride < 0 ) {
  		ix = (1-N) * stride;
  	} else {
  		ix = 0;
  	}
  	sum = 0.0;
  	c = 0.0;
  	for ( i = 0; i < N; i++ ) {
  		v = float64ToFloat32( alpha + x[ ix ] );
  		t = float64ToFloat32( sum + v );
  		if ( abs( sum ) >= abs( v ) ) {
  			c = float64ToFloat32( c + float64ToFloat32( float64ToFloat32( sum-t ) + v ) ); // eslint-disable-line max-len
  		} else {
  			c = float64ToFloat32( c + float64ToFloat32( float64ToFloat32( v-t ) + sum ) ); // eslint-disable-line max-len
  		}
  		sum = t;
  		ix += stride;
  	}
  	return float64ToFloat32( sum + c );
  }
  
  
  // EXPORTS //
  
  module.exports = sapxsumkbn;
  