Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 | 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x | /**
* @license Apache-2.0
*
* Copyright (c) 2025 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 isnan = require( '@stdlib/math/base/assert/is-nan' );
var abs = require( '@stdlib/math/base/special/abs' );
// MAIN //
/**
* Computes the cumulative sum of double-precision floating-point strided array elements ignoring `NaN` values and using an improved Kahan–Babuška algorithm.
*
* @param {PositiveInteger} N - number of indexed elements
* @param {number} sum - initial sum
* @param {Float64Array} x - input array
* @param {integer} strideX - stride length for `x`
* @param {NonNegativeInteger} offsetX - starting index for `x`
* @param {Float64Array} y - output array
* @param {integer} strideY - stride length `y`
* @param {NonNegativeInteger} offsetY - starting index for `y`
* @returns {Float64Array} output array
*
* @example
* var Float64Array = require( '@stdlib/array/float64' );
*
* var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, NaN, NaN ] );
* var y = new Float64Array( x.length );
*
* var v = dnancusumkbn( 4, 0.0, x, 2, 1, y, 1, 0 );
* // returns <Float64Array>[ 1.0, -1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0 ]
*/
function dnancusumkbn( N, sum, x, strideX, offsetX, y, strideY, offsetY ) {
var ix;
var iy;
var s;
var v;
var t;
var c;
var i;
if ( N <= 0 ) {
return y;
}
ix = offsetX;
iy = offsetY;
s = sum;
// In order to preserve the sign of zero which can be lost during compensated summation below, find the first non-zero element...
if ( s === 0.0 ) {
for ( i = 0; i < N; i++ ) {
v = x[ ix ];
if ( isnan( v ) ) {
y[ iy ] = s;
ix += strideX;
iy += strideY;
continue;
}
if ( v !== 0.0 ) {
break;
}
s += v;
y[ iy ] = s;
ix += strideX;
iy += strideY;
}
} else {
i = 0;
}
c = 0.0;
for ( ; i < N; i++ ) {
v = x[ ix ];
if ( isnan( v ) ) {
y[ iy ] = s + c;
ix += strideX;
iy += strideY;
continue;
}
t = s + v;
if ( abs( s ) >= abs( v ) ) {
c += (s-t) + v;
} else {
c += (v-t) + s;
}
s = t;
y[ iy ] = s + c;
ix += strideX;
iy += strideY;
}
return y;
}
// EXPORTS //
module.exports = dnancusumkbn;
|