feat: add C ndarray implementation for blas/base/ddot

PR-URL: #2936
Ref: #2039
Reviewed-by: Athan Reines <kgryte@gmail.com>

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

@@ -227,6 +227,32 @@ The function accepts the following arguments:
 double c_ddot( const CBLAS_INT N, const double *X, const CBLAS_INT strideX, const double *Y, const CBLAS_INT strideY );
 ```
 
+#### c_ddot_ndarray( N, \*X, strideX, offsetX, \*Y, strideY, offsetY )
+
+Computes the dot product of two double-precision floating-point vectors using alternative indexing semantics.
+
+```c
+const double x[] = { 4.0, 2.0, -3.0, 5.0, -1.0 };
+const double y[] = { 2.0, 6.0, -1.0, -4.0, 8.0 };
+
+double v = c_ddot_ndarray( 5, x, -1, 4, y, -1, 4 );
+// returns -5.0
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] double*` first input array.
+-   **strideX**: `[in] CBLAS_INT` index increment for `X`.
+-   **offsetX**: `[in] CBLAS_INT` starting index for `X`.
+-   **Y**: `[in] double*` second input array.
+-   **strideY**: `[in] CBLAS_INT` index increment for `Y`.
+-   **offsetY**: `[in] CBLAS_INT` starting index for `Y`.
+
+```c
+double c_ddot_ndarray( const CBLAS_INT N, const double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, const double *Y, const CBLAS_INT strideY. const CBLAS_INT offsetY );
+```
+
 </section>
 
 <!-- /.usage -->
@@ -266,6 +292,12 @@ int main( void ) {
 
     // Print the result:
     printf( "dot product: %lf\n", d );
+
+    // Compute the dot product:
+    d = c_ddot_ndarray( N, x, strideX, 0, y, strideY, N-1 );
+
+    // Print the result:
+    printf( "dot product: %lf\n", d );
 }
 ```
 

lib/node_modules/@stdlib/blas/base/ddot/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[ len ];
@@ -122,6 +122,41 @@ 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[ len ];
+	double z;
+	double t;
+	int i;
+
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = ( rand_double()*20000.0 ) - 10000.0;
+		y[ i ] = ( rand_double()*20000.0 ) - 10000.0;
+	}
+	z = 0.0;
+	t = tic();
+	for ( i = 0; i < iterations; i++ ) {
+		z = c_ddot_ndarray( len, x, 1, 0, y, 1, 0 );
+		if ( z != z ) {
+			printf( "should not return NaN\n" );
+			break;
+		}
+	}
+	elapsed = tic() - t;
+	if ( z != z ) {
+		printf( "should not return NaN\n" );
+	}
+	return elapsed;
+}
+
 /**
 * Main execution sequence.
 */
@@ -144,7 +179,14 @@ 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/ddot/examples/c/example.c

@@ -36,4 +36,10 @@ int main( void ) {
 
 	// Print the result:
 	printf( "dot product: %lf\n", d );
+
+	// Compute the dot product:
+	d = c_ddot_ndarray( N, x, strideX, 0, y, strideY, N-1 );
+
+	// Print the result:
+	printf( "dot product: %lf\n", d );
 }

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

@@ -36,6 +36,11 @@ extern "C" {
 */
 double API_SUFFIX(c_ddot)( const CBLAS_INT N, const double *X, const CBLAS_INT strideX, const double *Y, const CBLAS_INT strideY );
 
+/**
+* Computes the dot product of two double-precision floating-point vectors using alternative indexing semantics.
+*/
+double API_SUFFIX(c_ddot_ndarray)( const CBLAS_INT N, const double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, const double *Y, const CBLAS_INT strideY, const CBLAS_INT offsetY );
+
 #ifdef __cplusplus
 }
 #endif

lib/node_modules/@stdlib/blas/base/ddot/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( './ddot.native.js' );
+var addon = require( './../src/addon.node' );
 
 
 // MAIN //
@@ -49,16 +47,7 @@ var addon = require( './ddot.native.js' );
 * // returns -5.0
 */
 function ddot( N, x, strideX, offsetX, y, strideY, offsetY ) {
-	var viewX;
-	var viewY;
-
-	offsetX = minViewBufferIndex( N, strideX, offsetX );
-	offsetY = minViewBufferIndex( N, strideY, offsetY );
-
-	viewX = offsetView( x, offsetX );
-	viewY = offsetView( y, offsetY );
-
-	return addon( N, viewX, strideX, viewY, strideY );
+	return addon.ndarray( N, x, strideX, offsetX, y, strideY, offsetY );
 }