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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 | 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 30x 30x 30x 30x 30x 30x 30x 30x 30x 30x 30x 30x 4x 4x 26x 26x 26x 26x 30x 24x 31x 31x 5x 5x 5x 5x 5x 29x 22x 22x 4x 4x 4x 4x 4x 30x 2x 2x 26x 26x 30x 2081x 2081x 24x 24x 24x 24x 24x 2057x 2081x 2016x 2081x 41x 41x 2057x 2057x 2081x 2055x 2081x 2x 2x 2057x 2057x 2057x 2057x 2057x 2057x 2057x 26x 30x 3x 3x 3x 3x 3x | /**
* @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 f32 = require( '@stdlib/number/float64/base/to-float32' );
var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
var absf = require( '@stdlib/math/base/special/absf' );
// MAIN //
/**
* Computes the cumulative sum of single-precision floating-point strided array elements ignoring `NaN` values and 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 {number} sum - initial sum
* @param {Float32Array} x - input array
* @param {integer} strideX - stride length for `x`
* @param {NonNegativeInteger} offsetX - starting index for `x`
* @param {Float32Array} y - output array
* @param {integer} strideY - stride length `y`
* @param {NonNegativeInteger} offsetY - starting index for `y`
* @returns {Float32Array} output array
*
* @example
* var Float32Array = require( '@stdlib/array/float32' );
*
* var x = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, NaN, NaN ] );
* var y = new Float32Array( x.length );
*
* var v = snancusumkbn2( 4, 0.0, x, 2, 1, y, 1, 0 );
* // returns <Float32Array>[ 1.0, -1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0 ]
*/
function snancusumkbn2( N, sum, x, strideX, offsetX, y, strideY, offsetY ) {
var ccs;
var ix;
var iy;
var cs;
var cc;
var v;
var t;
var c;
var i;
if ( N <= 0 ) {
return y;
}
ix = offsetX;
iy = offsetY;
// In order to preserve the sign of zero which can be lost during compensated summation below, find the first non-zero element...
if ( sum === 0.0 ) {
for ( i = 0; i < N; i++ ) {
v = x[ ix ];
if ( isnanf( v ) ) {
y[ iy ] = sum;
ix += strideX;
iy += strideY;
continue;
}
if ( v !== 0.0 ) {
break;
}
sum = f32( sum + v );
y[ iy ] = sum;
ix += strideX;
iy += strideY;
}
} else {
i = 0;
}
ccs = 0.0; // second order correction term for lost low order bits
cs = 0.0; // first order correction term for lost low order bits
for ( ; i < N; i++ ) {
v = x[ ix ];
if ( isnanf( v ) ) {
y[ iy ] = f32( sum + f32( cs + ccs ) );
ix += strideX;
iy += strideY;
continue;
}
t = f32( sum + v );
if ( absf( sum ) >= absf( v ) ) {
c = f32( f32( sum - t ) + v );
} else {
c = f32( f32( v - t ) + sum );
}
sum = t;
t = f32( cs + c );
if ( absf( cs ) >= absf( c ) ) {
cc = f32( f32( cs - t ) + c );
} else {
cc = f32( f32( c - t ) + cs );
}
cs = t;
ccs = f32( ccs + cc );
y[ iy ] = f32( sum + f32( cs + ccs ) );
ix += strideX;
iy += strideY;
}
return y;
}
// EXPORTS //
module.exports = snancusumkbn2;
|