feat: add accessor array support to blas/base/gasum

PR-URL: #5439
Closes: stdlib-js/metr-issue-tracker#22
Reviewed-by: Athan Reines <[email protected]>

Author: headlessNode

lib/node_modules/@stdlib/blas/base/gasum/README.md

@@ -135,6 +135,7 @@ sum = gasum.ndarray( 3, x, -1, x.length-1 );
 
 -   If `N <= 0`, both functions return `0`.
 -   `gasum()` corresponds to the [BLAS][blas] level 1 function [`dasum`][dasum] with the exception that this implementation works with any array type, not just Float64Arrays. Depending on the environment, the typed versions ([`dasum`][@stdlib/blas/base/dasum], [`sasum`][@stdlib/blas/base/sasum], etc.) are likely to be significantly more performant.
+-   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]).
 
 </section>
 
@@ -199,6 +200,8 @@ console.log( y );
 
 [@stdlib/blas/base/sasum]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/blas/base/sasum
 
+[@stdlib/array/base/accessor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/base/accessor
+
 <!-- <related-links> -->
 
 <!-- </related-links> -->

lib/node_modules/@stdlib/blas/base/gasum/docs/types/index.d.ts

@@ -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 `gasum`.
@@ -40,7 +45,7 @@ interface Routine {
 	* var z = gasum( x.length, x, 1 );
 	* // returns 15.0
 	*/
-	( N: number, x: NumericArray, stride: number ): number;
+	( N: number, x: InputArray, stride: number ): number;
 
 	/**
 	* Computes the sum of the absolute values using alternative indexing semantics.
@@ -57,7 +62,7 @@ interface Routine {
 	* var z = gasum.ndarray( x.length, x, 1, 0 );
 	* // returns 21.0
 	*/
-	ndarray( N: number, x: NumericArray, stride: number, offset: number ): number;
+	ndarray( N: number, x: InputArray, stride: number, offset: number ): number;
 }
 
 /**

lib/node_modules/@stdlib/blas/base/gasum/docs/types/test.ts

@@ -16,6 +16,7 @@
 * limitations under the License.
 */
 
+import AccessorArray = require( '@stdlib/array/base/accessor' );
 import gasum = require( './index' );
 
 
@@ -26,6 +27,7 @@ import gasum = require( './index' );
 	const x = new Float64Array( 10 );
 
 	gasum( x.length, x, 1 ); // $ExpectType number
+	gasum( 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...
@@ -86,6 +88,7 @@ import gasum = require( './index' );
 	const x = new Float64Array( 10 );
 
 	gasum.ndarray( x.length, x, 1, 0 ); // $ExpectType number
+	gasum.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...

lib/node_modules/@stdlib/blas/base/gasum/lib/accessors.js

@@ -0,0 +1,101 @@
+/**
+* @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 abs = require( '@stdlib/math/base/special/abs' );
+
+
+// VARIABLES //
+
+var M = 6;
+
+
+// MAIN //
+
+/**
+* Computes the sum of absolute values.
+*
+* @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} stride - index increment
+* @param {NonNegativeInteger} offset - starting index
+* @returns {number} sum
+*
+* @example
+* var toAccessorArray = require( '@stdlib/array/base/to-accessor-array' );
+* var arraylike2object = require( '@stdlib/array/base/arraylike2object' );
+*
+* var x = [ 1.0, -2.0, 3.0, -4.0, 5.0 ];
+*
+* var s = gasum( x.length, arraylike2object( toAccessorArray( x ) ), 1, 0 );
+* // returns 15.0
+*/
+function gasum( N, x, stride, offset ) {
+	var buf;
+	var get;
+	var sum;
+	var ix;
+	var m;
+	var i;
+
+	buf = x.data;
+	get = x.accessors[ 0 ];
+
+	sum = 0.0;
+	ix = offset;
+	if ( stride === 0 ) {
+		sum = abs( get( buf, ix ) * N );
+		return sum;
+	}
+
+	// Use unrolled loops if the stride is equal to `1`...
+	if ( stride === 1 ) {
+		m = N % M;
+
+		// If we have a remainder, run a clean-up loop...
+		if ( m > 0 ) {
+			for ( i = 0; i < m; i++ ) {
+				sum += abs( get( buf, ix ) );
+				ix += stride;
+			}
+		}
+		if ( N < M ) {
+			return sum;
+		}
+		for ( i = m; i < N; i += M ) {
+			sum += abs( get( buf, ix ) ) + abs( get( buf, ix+1 ) ) + abs( get( buf, ix+2 ) ) + abs( get( buf, ix+3 ) ) + abs( get( buf, ix+4 ) ) + abs( get( buf, ix+5 ) ); // eslint-disable-line max-len
+			ix += M;
+		}
+		return sum;
+	}
+	for ( i = 0; i < N; i++ ) {
+		sum += abs( get( buf, ix ) );
+		ix += stride;
+	}
+	return sum;
+}
+
+
+// EXPORTS //
+
+module.exports = gasum;

lib/node_modules/@stdlib/blas/base/gasum/lib/main.js

@@ -20,12 +20,8 @@
 
 // MODULES //
 
-var abs = require( '@stdlib/math/base/special/abs' );
-
-
-// VARIABLES //
-
-var M = 6;
+var stride2offset = require( '@stdlib/strided/base/stride2offset' );
+var ndarray = require( './ndarray.js' );
 
 
 // MAIN //
@@ -42,40 +38,10 @@ var M = 6;
 * var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0 ] );
 *
 * var s = gasum( x.length, x, 1 );
-* // 15.0
+* // returns 15.0
 */
 function gasum( N, x, stride ) {
-	var sum;
-	var m;
-	var i;
-
-	sum = 0.0;
-	if ( N <= 0 || stride <= 0 ) {
-		return sum;
-	}
-	// Use unrolled loops if the stride is equal to `1`...
-	if ( stride === 1 ) {
-		m = N % M;
-
-		// If we have a remainder, run a clean-up loop...
-		if ( m > 0 ) {
-			for ( i = 0; i < m; i++ ) {
-				sum += abs( x[i] );
-			}
-		}
-		if ( N < M ) {
-			return sum;
-		}
-		for ( i = m; i < N; i += M ) {
-			sum += abs(x[i]) + abs(x[i+1]) + abs(x[i+2]) + abs(x[i+3]) + abs(x[i+4]) + abs(x[i+5]); // eslint-disable-line max-len
-		}
-		return sum;
-	}
-	N *= stride;
-	for ( i = 0; i < N; i += stride ) {
-		sum += abs( x[i] );
-	}
-	return sum;
+	return ndarray( N, x, stride, stride2offset( N, stride ) );
 }
 
 

lib/node_modules/@stdlib/blas/base/gasum/lib/ndarray.js

@@ -21,6 +21,8 @@
 // MODULES //
 
 var abs = require( '@stdlib/math/base/special/abs' );
+var arraylike2object = require( '@stdlib/array/base/arraylike2object' );
+var accessors = require( './accessors.js' );
 
 
 // VARIABLES //
@@ -43,19 +45,29 @@ var M = 6;
 * var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0 ] );
 *
 * var s = gasum( x.length, x, 1, 0 );
-* // 15.0
+* // returns 15.0
 */
 function gasum( N, x, stride, offset ) {
 	var sum;
 	var ix;
 	var m;
 	var i;
+	var o;
 
 	sum = 0.0;
 	if ( N <= 0 ) {
 		return sum;
 	}
+	o = arraylike2object( x );
+	if ( o.accessorProtocol ) {
+		return accessors( N, o, stride, offset );
+	}
+
 	ix = offset;
+	if ( stride === 0 ) {
+		sum = abs( x[ix] * N );
+		return sum;
+	}
 
 	// Use unrolled loops if the stride is equal to `1`...
 	if ( stride === 1 ) {