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3 changes: 3 additions & 0 deletions lib/node_modules/@stdlib/blas/ext/base/gnansumkbn2/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,7 @@ var v = gnansumkbn2.ndarray( 5, x, 2, 1 );
## Notes

- If `N <= 0`, both functions return `0.0`.
- Both functions support array-like objects having getter and setter accessors for array element access (e.g., [`@stdlib/array/base/accessor`][@stdlib/array/base/accessor])
- Depending on the environment, the typed versions ([`dnansumkbn2`][@stdlib/blas/ext/base/dnansumkbn2], [`snansumkbn2`][@stdlib/blas/ext/base/snansumkbn2], etc.) are likely to be significantly more performant.

</section>
Expand Down Expand Up @@ -185,6 +186,8 @@ console.log( v );

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

[@stdlib/array/base/accessor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/base/accessor

[@klein:2005a]: https://doi.org/10.1007/s00607-005-0139-x

<!-- <related-links> -->
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,12 @@

/// <reference types="@stdlib/types"/>

import { NumericArray } from '@stdlib/types/array';
import { NumericArray, Collection, AccessorArrayLike } from '@stdlib/types/array';

/**
* Input array.
*/
type InputArray = NumericArray | Collection<number> | AccessorArrayLike<number>;

/**
* Interface describing `gnansumkbn2`.
Expand All @@ -40,7 +45,7 @@ interface Routine {
* var v = gnansumkbn2( x.length, x, 1 );
* // returns 1.0
*/
( N: number, x: NumericArray, strideX: number ): number;
( N: number, x: InputArray, strideX: number ): number;

/**
* Computes the sum of strided array elements, ignoring `NaN` values and using a second-order iterative Kahan–Babuška algorithm and alternative indexing semantics.
Expand All @@ -57,7 +62,7 @@ interface Routine {
* var v = gnansumkbn2.ndarray( x.length, x, 1, 0 );
* // returns 1.0
*/
ndarray( N: number, x: NumericArray, strideX: number, offsetX: number ): number;
ndarray( N: number, x: InputArray, strideX: number, offsetX: number ): number;
}

/**
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
* limitations under the License.
*/

import AccessorArray = require( '@stdlib/array/base/accessor' );
import gnansumkbn2 = require( './index' );


Expand All @@ -26,6 +27,7 @@ import gnansumkbn2 = require( './index' );
const x = new Float64Array( 10 );

gnansumkbn2( x.length, x, 1 ); // $ExpectType number
gnansumkbn2( x.length, new AccessorArray( x ), 1 ); // $ExpectType number
}

// The compiler throws an error if the function is provided a first argument which is not a number...
Expand Down Expand Up @@ -85,6 +87,7 @@ import gnansumkbn2 = require( './index' );
const x = new Float64Array( 10 );

gnansumkbn2.ndarray( x.length, x, 1, 0 ); // $ExpectType number
gnansumkbn2.ndarray( x.length, new AccessorArray( x ), 1, 0 ); // $ExpectType number
}

// The compiler throws an error if the `ndarray` method is provided a first argument which is not a number...
Expand Down
114 changes: 114 additions & 0 deletions lib/node_modules/@stdlib/blas/ext/base/gnansumkbn2/lib/accessors.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,114 @@
/**
* @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 sum of 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).
*
* @private
* @param {PositiveInteger} N - number of indexed elements
* @param {Object} x - input array object
* @param {Collection} x.data - input array data
* @param {Array<Function>} x.accessors - array element accessors
* @param {integer} strideX - stride length for `x`
* @param {NonNegativeInteger} offsetX - starting index for `x`
* @returns {number} sum
*
* @example
* var toAccessorArray = require( '@stdlib/array/base/to-accessor-array' );
* var arraylike2object = require( '@stdlib/array/base/arraylike2object' );
*
* var x = toAccessorArray( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
*
* var v = gnansumkbn2( 4, arraylike2object( x ), 2, 1 );
* // returns 5.0
*/
function gnansumkbn2( N, x, strideX, offsetX ) {
var xbuf;
var xget;
var sum;
var ccs;
var cs;
var cc;
var ix;
var v;
var t;
var c;
var i;

// Cache reference to array data:
xbuf = x.data;

// Cache reference to the element accessors:
xget = x.accessors[ 0 ];

ix = offsetX;
if ( strideX === 0 ) {
if ( isnan( xget( xbuf, ix ) ) ) {
return 0.0;
}
return N * xget( xbuf, ix );
}
sum = 0.0;
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 = 0; i < N; i++ ) {
v = xget( xbuf, ix );
if ( isnan( v ) === false ) {
t = sum + v;
if ( abs( sum ) >= abs( v ) ) {
c = (sum-t) + v;
} else {
c = (v-t) + sum;
}
sum = t;
t = cs + c;
if ( abs( cs ) >= abs( c ) ) {
cc = (cs-t) + c;
} else {
cc = (c-t) + cs;
}
cs = t;
ccs += cc;
}
ix += strideX;
}
return sum + cs + ccs;
}


// EXPORTS //

module.exports = gnansumkbn2;
Original file line number Diff line number Diff line change
Expand Up @@ -20,8 +20,10 @@

// MODULES //

var arraylike2object = require( '@stdlib/array/base/arraylike2object' );
var isnan = require( '@stdlib/math/base/assert/is-nan' );
var abs = require( '@stdlib/math/base/special/abs' );
var accessors = require( './accessors.js' );


// MAIN //
Expand Down Expand Up @@ -58,11 +60,16 @@ function gnansumkbn2( N, x, strideX, offsetX ) {
var v;
var t;
var c;
var o;
var i;

if ( N <= 0 ) {
return 0.0;
}
o = arraylike2object( x );
if ( o.accessorProtocol ) {
return accessors( N, o, strideX, offsetX );
}
ix = offsetX;
if ( strideX === 0 ) {
if ( isnan( x[ ix ] ) ) {
Expand Down
106 changes: 106 additions & 0 deletions lib/node_modules/@stdlib/blas/ext/base/gnansumkbn2/test/test.main.js
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@

var tape = require( 'tape' );
var Float64Array = require( '@stdlib/array/float64' );
var toAccessorArray = require( '@stdlib/array/base/to-accessor-array' );
var gnansumkbn2 = require( './../lib' );


Expand Down Expand Up @@ -73,6 +74,41 @@ tape( 'the function calculates the sum of strided array elements (ignoring NaN v
t.end();
});

tape( 'the function calculates the sum of strided array elements (ignoring NaN values, accessors)', function test( t ) {
var x;
var v;

x = [ 1.0, -2.0, -4.0, 5.0, 0.0, NaN, 3.0, 0.0, -3.0, 3.0 ];
v = gnansumkbn2( x.length, toAccessorArray( x ), 1 );
t.strictEqual( v, 3.0, 'returns expected value' );

x = [ 1.0, -2.0, -4.0, NaN, 5.0, 0.0, 3.0 ];
v = gnansumkbn2( x.length, toAccessorArray( x ), 1 );
t.strictEqual( v, 3.0, 'returns expected value' );

x = [ -4.0, NaN, -4.0 ];
v = gnansumkbn2( x.length, toAccessorArray( x ), 1 );
t.strictEqual( v, -8.0, 'returns expected value' );

x = [ NaN, 4.0 ];
v = gnansumkbn2( x.length, toAccessorArray( x ), 1 );
t.strictEqual( v, 4.0, 'returns expected value' );

x = [ NaN, NaN ];
v = gnansumkbn2( x.length, toAccessorArray( x ), 1 );
t.strictEqual( v, 0.0, 'returns expected value' );

x = [ NaN ];
v = gnansumkbn2( x.length, toAccessorArray( x ), 1 );
t.strictEqual( v, 0.0, 'returns expected value' );

x = [ 1.0, 1.0e100, 1.0, -1.0e100 ];
v = gnansumkbn2( x.length, toAccessorArray( x ), 1 );
t.strictEqual( v, 2.0, 'returns expected value' );

t.end();
});

tape( 'if provided an `N` parameter less than or equal to `0`, the function returns `0.0`', function test( t ) {
var x;
var v;
Expand Down Expand Up @@ -123,6 +159,29 @@ tape( 'the function supports a `stride` parameter', function test( t ) {
t.end();
});

tape( 'the function supports a `stride` parameter (accessors)', function test( t ) {
var x;
var v;

x = [
1.0, // 0
2.0,
2.0, // 1
-7.0,
-2.0, // 2
3.0,
4.0, // 3
2.0,
NaN, // 4
NaN
];

v = gnansumkbn2( 5, toAccessorArray( x ), 2 );

t.strictEqual( v, 5.0, 'returns expected value' );
t.end();
});

tape( 'the function supports a negative `stride` parameter', function test( t ) {
var x;
var v;
Expand All @@ -146,6 +205,29 @@ tape( 'the function supports a negative `stride` parameter', function test( t )
t.end();
});

tape( 'the function supports a negative `stride` parameter (accessors)', function test( t ) {
var x;
var v;

x = [
NaN, // 4
NaN,
1.0, // 3
2.0,
2.0, // 2
-7.0,
-2.0, // 1
3.0,
4.0, // 0
2.0
];

v = gnansumkbn2( 5, toAccessorArray( x ), -2 );

t.strictEqual( v, 5.0, 'returns expected value' );
t.end();
});

tape( 'if provided a `stride` parameter equal to `0`, the function returns the sum of the first element repeated N times', function test( t ) {
var x;
var v;
Expand All @@ -158,6 +240,18 @@ tape( 'if provided a `stride` parameter equal to `0`, the function returns the s
t.end();
});

tape( 'if provided a `stride` parameter equal to `0`, the function returns the sum of the first element repeated N times (accessors)', function test( t ) {
var x;
var v;

x = [ 1.0, -2.0, -4.0, 5.0, 3.0 ];

v = gnansumkbn2( x.length, toAccessorArray( x ), 0 );
t.strictEqual( v, 5.0, 'returns expected value' );

t.end();
});

tape( 'if provided a `stride` parameter equal to `0` and the first element is NaN, the function returns 0', function test( t ) {
var x;
var v;
Expand All @@ -170,6 +264,18 @@ tape( 'if provided a `stride` parameter equal to `0` and the first element is Na
t.end();
});

tape( 'if provided a `stride` parameter equal to `0` and the first element is NaN, the function returns 0 (accessors)', function test( t ) {
var x;
var v;

x = [ NaN, -2.0, -4.0, 5.0, 3.0 ];

v = gnansumkbn2( x.length, toAccessorArray( x ), 0 );
t.strictEqual( v, 0.0, 'returns expected value' );

t.end();
});

tape( 'the function supports view offsets', function test( t ) {
var x0;
var x1;
Expand Down
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