feat: update JavaScript implementation and add C ndarray implementation for blas/base/cscal

PR-URL: #2967
Ref: #2039
Co-authored-by: Athan Reines <[email protected]>
Reviewed-by: Athan Reines <[email protected]> 
Signed-off-by: Athan Reines <[email protected]>

Author: aman-095

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

@@ -251,7 +251,7 @@ Scales values from `CX` by `ca`.
 float cx[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
 const stdlib_complex64_t ca = stdlib_complex64( 2.0f, 2.0f );
 
-c_dscal( 4, ca, (void *)cx, 1 );
+c_cscal( 4, ca, (void *)cx, 1 );
 ```
 
 The function accepts the following arguments:
@@ -262,7 +262,32 @@ The function accepts the following arguments:
 -   **strideX**: `[in] CBLAS_INT` index increment for `CX`.
 
 ```c
-void c_dscal( const CBLAS_INT N, const stdlib_complex64_t ca, void *CX, const CBLAS_INT strideX );
+void c_cscal( const CBLAS_INT N, const stdlib_complex64_t ca, void *CX, const CBLAS_INT strideX );
+```
+
+#### c_cscal_ndarray( N, ca, \*CX, strideX, offsetX )
+
+Scales values from `CX` by `ca` using alternative indexing semantics.
+
+```c
+#include "stdlib/complex/float32/ctor.h"
+
+float cx[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
+const stdlib_complex64_t ca = stdlib_complex64( 2.0f, 2.0f );
+
+c_cscal( 4, ca, (void *)cx, 1, 0 );
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **ca**: `[in] stdlib_complex64_t` scalar constant.
+-   **CX**: `[inout] void*` input array.
+-   **strideX**: `[in] CBLAS_INT` index increment for `CX`.
+-   **offsetX**: `[in] CBLAS_INT` starting index for `CX`.
+
+```c
+void c_cscal_ndarray( const CBLAS_INT N, const stdlib_complex64_t ca, void *CX, const CBLAS_INT strideX, const CBLAS_INT offsetX );
 ```
 
 </section>
@@ -308,6 +333,14 @@ int main( void ) {
     for ( int i = 0; i < N; i++ ) {
         printf( "cx[ %i ] = %f + %fj\n", i, cx[ i*2 ], cx[ (i*2)+1 ] );
     }
+
+    // Scale the elements of the array:
+    c_cscal_ndarray( N, ca, (void *)cx, -strideX, 3 );
+
+    // Print the result:
+    for ( int i = 0; i < N; i++ ) {
+        printf( "cx[ %i ] = %f + %fj\n", i, cx[ i*2 ], cx[ (i*2)+1 ] );
+    }
 }
 ```
 

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

@@ -95,7 +95,7 @@ static float rand_float( void ) {
 * @param len          array length
 * @return elapsed time in seconds
 */
-static double benchmark( int iterations, int len ) {
+static double benchmark1( int iterations, int len ) {
 	stdlib_complex64_t ca;
 	float cx[ len*2 ];
 	double elapsed;
@@ -122,6 +122,40 @@ 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 ) {
+	stdlib_complex64_t ca;
+	float cx[ len*2 ];
+	double elapsed;
+	double t;
+	int i;
+
+	ca = stdlib_complex64( 1.0f, 0.0f );
+	for ( i = 0; i < len*2; i += 2 ) {
+		cx[ i ] = ( rand_float()*2.0f ) - 1.0f;
+		cx[ i+1 ] = ( rand_float()*2.0f ) - 1.0f;
+	}
+	t = tic();
+	for ( i = 0; i < iterations; i++ ) {
+		c_cscal_ndarray( len, ca, (void *)cx, 1, 0 );
+		if ( cx[ 0 ] != cx[ 0 ] ) {
+			printf( "should not return NaN\n" );
+			break;
+		}
+	}
+	elapsed = tic() - t;
+	if ( cx[ 0 ] != cx[ 0 ] ) {
+		printf( "should not return NaN\n" );
+	}
+	return elapsed;
+}
+
 /**
 * Main execution sequence.
 */
@@ -144,7 +178,14 @@ 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/cscal/docs/repl.txt

@@ -9,8 +9,7 @@
     Indexing is relative to the first index. To introduce an offset, use typed
     array views.
 
-    If `N` or `strideX` is less than or equal to `0`, the function returns `cx`
-    unchanged.
+    If `N` is less than or equal to `0`, the function returns `cx` unchanged.
 
 
     Parameters

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

@@ -40,4 +40,12 @@ int main( void ) {
 	for ( int i = 0; i < N; i++ ) {
 		printf( "cx[ %i ] = %f + %fj\n", i, cx[ i*2 ], cx[ (i*2)+1 ] );
 	}
+
+	// Scale the elements of the array:
+	c_cscal_ndarray( N, ca, (void *)cx, -strideX, 3 );
+
+	// Print the result:
+	for ( int i = 0; i < N; i++ ) {
+		printf( "cx[ %i ] = %f + %fj\n", i, cx[ i*2 ], cx[ (i*2)+1 ] );
+	}
 }

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

@@ -37,6 +37,11 @@ extern "C" {
 */
 void API_SUFFIX(c_cscal)( const CBLAS_INT N, const stdlib_complex64_t ca, void *CX, const CBLAS_INT strideX );
 
+/**
+* Scales a single-precision complex floating-point vector by a single-precision complex floating-point constant using alternative indexing semantics.
+*/
+void API_SUFFIX(c_cscal_ndarray)( const CBLAS_INT N, const stdlib_complex64_t ca, void *CX, const CBLAS_INT strideX, const CBLAS_INT offsetX );
+
 #ifdef __cplusplus
 }
 #endif

lib/node_modules/@stdlib/blas/base/cscal/lib/cscal.js

@@ -20,7 +20,8 @@
 
 // MODULES //
 
-var cmulf = require( '@stdlib/complex/float32/base/mul' );
+var stride2offset = require( '@stdlib/strided/base/stride2offset' );
+var ndarray = require( './ndarray.js' );
 
 
 // MAIN //
@@ -55,26 +56,8 @@ var cmulf = require( '@stdlib/complex/float32/base/mul' );
 * // returns 6.0
 */
 function cscal( N, ca, cx, strideX ) {
-	var ix;
-	var i;
-
-	if ( N <= 0 || strideX <= 0 ) {
-		return cx;
-	}
-	if ( strideX === 1 ) {
-		// Code for stride equal to `1`...
-		for ( i = 0; i < N; i++ ) {
-			cx.set( cmulf( ca, cx.get( i ) ), i );
-		}
-		return cx;
-	}
-	// Code for stride not equal to `1`...
-	ix = 0;
-	for ( i = 0; i < N; i++ ) {
-		cx.set( cmulf( ca, cx.get( ix ) ), ix );
-		ix += strideX;
-	}
-	return cx;
+	var ox = stride2offset( N, strideX );
+	return ndarray( N, ca, cx, strideX, ox );
 }
 
 

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

@@ -59,7 +59,7 @@ function cscal( N, ca, cx, strideX, offsetX ) {
 	var ix;
 	var i;
 
-	if ( N <= 0 || strideX <= 0 ) {
+	if ( N <= 0 ) {
 		return cx;
 	}
 	ix = offsetX;

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

@@ -21,7 +21,6 @@
 // MODULES //
 
 var reinterpret = require( '@stdlib/strided/base/reinterpret-complex64' );
-var minViewBufferIndex = require( '@stdlib/strided/base/min-view-buffer-index' );
 var addon = require( './../src/addon.node' );
 
 
@@ -58,10 +57,8 @@ var addon = require( './../src/addon.node' );
 * // returns 6.0
 */
 function cscal( N, ca, cx, strideX, offsetX ) {
-	var viewCX;
-	offsetX = minViewBufferIndex( N, strideX, offsetX );
-	viewCX = reinterpret( cx, offsetX );
-	addon( N, ca, viewCX, strideX );
+	var viewCX = reinterpret( cx, 0 );
+	addon.ndarray( N, ca, viewCX, strideX, offsetX );
 	return cx;
 }