feat: refactor JavaScript implementation and add C ndarray implemen…

…tation for `blas/base/dasum`

PR-URL: #2942
Ref: #2039
Reviewed-by: Athan Reines <kgryte@gmail.com>

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

@@ -97,7 +97,7 @@ var sum = dasum( 3, x1, 2 );
 // returns 12.0
 ```
 
-If either `N` or `stride` is less than or equal to `0`, the function returns `0`.
+If `N` is less than or equal to `0`, the function returns `0`.
 
 #### dasum.ndarray( N, x, stride, offset )
 
@@ -217,6 +217,28 @@ The function accepts the following arguments:
 double c_dasum( const CBLAS_INT N, const double *X, const CBLAS_INT stride );
 ```
 
+#### c_dasum_ndarray( N, \*X, stride, offset )
+
+Computes the sum of absolute values using alternative indexing semantics.
+
+```c
+const double x[] = { 1.0, 2.0, 3.0, 4.0 };
+
+double v = c_dasum_ndarray( 4, x, -1, 3 );
+// returns 10.0
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] double*` input array.
+-   **stride**: `[in] CBLAS_INT` index increment for `X`.
+-   **offset**: `[in] CBLAS_INT` starting index for `X`.
+
+```c
+double c_dasum_ndarray( const CBLAS_INT N, const double *X, const CBLAS_INT stride, const CBLAS_INT offset );
+```
+
 </section>
 
 <!-- /.usage -->
@@ -254,6 +276,12 @@ int main( void ) {
 
     // Print the result:
     printf( "sum: %lf\n", sum );
+
+    // Compute the sum of absolute values:
+    sum = c_dasum_ndarray( N, x, -strideX, N-1 );
+
+    // Print the result:
+    printf( "sum: %lf\n", sum );
 }
 ```
 

lib/node_modules/@stdlib/blas/base/dasum/benchmark/c/benchmark.length.c

@@ -94,7 +94,7 @@ static double rand_double( void ) {
 * @param len          array length
 * @return elapsed time in seconds
 */
-static double benchmark( int iterations, int len ) {
+static double benchmark1( int iterations, int len ) {
 	double elapsed;
 	double x[ len ];
 	double y;
@@ -120,6 +120,39 @@ static double benchmark( int iterations, int len ) {
 	return elapsed;
 }
 
+/**
+* Runs a benchmark.
+*
+* @param iterations   number of iterations
+* @param len          array length
+* @return elapsed time in seconds
+*/
+static double benchmark2( int iterations, int len ) {
+	double elapsed;
+	double x[ len ];
+	double y;
+	double t;
+	int i;
+
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = ( rand_double()*20000.0 ) - 10000.0;
+	}
+	y = 0.0;
+	t = tic();
+	for ( i = 0; i < iterations; i++ ) {
+		y = c_dasum_ndarray( len, x, 1, 0 );
+		if ( y != y ) {
+			printf( "should not return NaN\n" );
+			break;
+		}
+	}
+	elapsed = tic() - t;
+	if ( y != y ) {
+		printf( "should not return NaN\n" );
+	}
+	return elapsed;
+}
+
 /**
 * Main execution sequence.
 */
@@ -142,7 +175,14 @@ int main( void ) {
 		for ( j = 0; j < REPEATS; j++ ) {
 			count += 1;
 			printf( "# c::%s:len=%d\n", NAME, len );
-			elapsed = benchmark( iter, len );
+			elapsed = benchmark1( iter, len );
+			print_results( iter, elapsed );
+			printf( "ok %d benchmark finished\n", count );
+		}
+		for ( j = 0; j < REPEATS; j++ ) {
+			count += 1;
+			printf( "# c::%s:ndarray:len=%d\n", NAME, len );
+			elapsed = benchmark2( iter, len );
 			print_results( iter, elapsed );
 			printf( "ok %d benchmark finished\n", count );
 		}

lib/node_modules/@stdlib/blas/base/dasum/docs/repl.txt

@@ -10,7 +10,7 @@
     Indexing is relative to the first index. To introduce an offset, use typed
     array views.
 
-    If `N` or `stride` is less than or equal to `0`, the function returns `0`.
+    If `N` is less than or equal to `0`, the function returns `0`.
 
     Parameters
     ----------

lib/node_modules/@stdlib/blas/base/dasum/examples/c/example.c

@@ -34,4 +34,10 @@ int main( void ) {
 
 	// Print the result:
 	printf( "sum: %lf\n", sum );
+
+	// Compute the sum of absolute values:
+	sum = c_dasum_ndarray( N, x, -strideX, N-1 );
+
+	// Print the result:
+	printf( "sum: %lf\n", sum );
 }

lib/node_modules/@stdlib/blas/base/dasum/include/stdlib/blas/base/dasum.h

@@ -36,6 +36,11 @@ extern "C" {
 */
 double API_SUFFIX(c_dasum)( const CBLAS_INT N, const double *X, const CBLAS_INT stride );
 
+/**
+* Computes the sum of absolute values using alternative indexing semantics.
+*/
+double API_SUFFIX(c_dasum_ndarray)( const CBLAS_INT N, const double *X, const CBLAS_INT stride, const CBLAS_INT offset );
+
 #ifdef __cplusplus
 }
 #endif

lib/node_modules/@stdlib/blas/base/dasum/lib/dasum.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 //
@@ -35,7 +31,7 @@ var M = 6;
 *
 * @param {PositiveInteger} N - number of indexed elements
 * @param {Float64Array} x - input array
-* @param {PositiveInteger} stride - `x` stride length
+* @param {integer} stride - `x` stride length
 * @returns {number} sum
 *
 * @example
@@ -47,37 +43,8 @@ var M = 6;
 * // returns 15.0
 */
 function dasum( 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;
+	var ox = stride2offset( N, stride );
+	return ndarray( N, x, stride, ox );
 }
 
 

lib/node_modules/@stdlib/blas/base/dasum/lib/dasum.native.js

@@ -30,7 +30,7 @@ var addon = require( './../src/addon.node' );
 *
 * @param {PositiveInteger} N - number of indexed elements
 * @param {Float64Array} x - input array
-* @param {PositiveInteger} stride - `x` stride length
+* @param {integer} stride - `x` stride length
 * @returns {number} sum
 *
 * @example

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

@@ -23,11 +23,6 @@
 var abs = require( '@stdlib/math/base/special/abs' );
 
 
-// VARIABLES //
-
-var M = 6;
-
-
 // MAIN //
 
 /**
@@ -36,7 +31,7 @@ var M = 6;
 * @param {PositiveInteger} N - number of indexed elements
 * @param {Float64Array} x - input array
 * @param {integer} stride - `x` stride length
-* @param {NonNegativeInteger} offset - starting `x` index
+* @param {NonNegativeInteger} offset - starting index for `x`
 * @returns {number} sum
 *
 * @example
@@ -50,35 +45,13 @@ var M = 6;
 function dasum( N, x, stride, offset ) {
 	var sum;
 	var ix;
-	var m;
 	var i;
 
 	sum = 0.0;
 	if ( N <= 0 ) {
 		return sum;
 	}
 	ix = offset;
-
-	// 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[ix] );
-				ix += stride;
-			}
-		}
-		if ( N < M ) {
-			return sum;
-		}
-		for ( i = m; i < N; i += M ) {
-			sum += abs( x[ix] ) + abs( x[ix+1] ) + abs( x[ix+2] ) + abs( x[ix+3] ) + abs( x[ix+4] ) + abs( x[ix+5] ); // eslint-disable-line max-len
-			ix += M;
-		}
-		return sum;
-	}
 	for ( i = 0; i < N; i++ ) {
 		sum += abs( x[ix] );
 		ix += stride;

lib/node_modules/@stdlib/blas/base/dasum/lib/ndarray.native.js

@@ -20,9 +20,7 @@
 
 // MODULES //
 
-var minViewBufferIndex = require( '@stdlib/strided/base/min-view-buffer-index' );
-var offsetView = require( '@stdlib/strided/base/offset-view' );
-var addon = require( './dasum.native.js' );
+var addon = require( './../src/addon.node' );
 
 
 // MAIN //
@@ -33,7 +31,7 @@ var addon = require( './dasum.native.js' );
 * @param {PositiveInteger} N - number of indexed elements
 * @param {Float64Array} x - input array
 * @param {integer} stride - `x` stride length
-* @param {NonNegativeInteger} offset - starting `x` index
+* @param {NonNegativeInteger} offset - starting index for `x`
 * @returns {number} sum
 *
 * @example
@@ -45,13 +43,7 @@ var addon = require( './dasum.native.js' );
 * // returns 15.0
 */
 function dasum( N, x, stride, offset ) {
-	var view;
-	offset = minViewBufferIndex( N, stride, offset );
-	if ( stride < 0 ) {
-		stride *= -1;
-	}
-	view = offsetView( x, offset );
-	return addon( N, view, stride );
+	return addon.ndarray( N, x, stride, offset );
 }