feat: add C ndarray API and refactor blas/ext/base/snansum

lib/node_modules/@stdlib/blas/ext/base/snansum/README.md

@@ -36,7 +36,7 @@ limitations under the License.
 var snansum = require( '@stdlib/blas/ext/base/snansum' );
 ```
 
-#### snansum( N, x, stride )
+#### snansum( N, x, strideX )
 
 Computes the sum of single-precision floating-point strided array elements, ignoring `NaN` values.
 
@@ -53,9 +53,9 @@ The function has the following parameters:
 
 -   **N**: number of indexed elements.
 -   **x**: input [`Float32Array`][@stdlib/array/float32].
--   **stride**: index increment for `x`.
+-   **strideX**: stride length.
 
-The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to compute the sum of every other element in `x`,
+The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to compute the sum of every other element:
 
 ```javascript
 var Float32Array = require( '@stdlib/array/float32' );
@@ -80,7 +80,7 @@ var v = snansum( 4, x1, 2 );
 // returns 5.0
 ```
 
-#### snansum.ndarray( N, x, stride, offset )
+#### snansum.ndarray( N, x, strideX, offsetX )
 
 Computes the sum of single-precision floating-point strided array elements, ignoring `NaN` values and using alternative indexing semantics.
 
@@ -95,9 +95,9 @@ var v = snansum.ndarray( 4, x, 1, 0 );
 
 The function has the following additional parameters:
 
--   **offset**: starting index for `x`.
+-   **offsetX**: starting index.
 
-While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the `offset` parameter supports indexing semantics based on a starting index. For example, to calculate the sum of every other value in `x` starting from the second value
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to calculate the sum of every other element starting from the second element:
 
 ```javascript
 var Float32Array = require( '@stdlib/array/float32' );
@@ -135,7 +135,7 @@ var filledarrayBy = require( '@stdlib/array/filled-by' );
 var snansum = require( '@stdlib/blas/ext/base/snansum' );
 
 function rand() {
-    if ( bernoulli( 0.8 ) > 0 ) {
+    if ( bernoulli( 0.5 ) < 1 ) {
         return discreteUniform( 0, 100 );
     }
     return NaN;
@@ -152,6 +152,123 @@ console.log( v );
 
 <!-- /.examples -->
 
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- C usage documentation. -->
+
+<section class="usage">
+
+### Usage
+
+```c
+#include "stdlib/blas/ext/base/snansum.h"
+```
+
+#### stdlib_strided_snansum( N, \*X, strideX )
+
+Computes the sum of single-precision floating-point strided array elements, ignoring `NaN` values.
+
+```c
+const float x[] = { 1.0f, 2.0f, 0.0f/0.0f, 4.0f };
+
+float v = stdlib_strided_snansum( 4, x, 1 );
+// returns 7.0f
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] float*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length.
+
+```c
+float stdlib_strided_snansum( const CBLAS_INT N, const float *X, const CBLAS_INT strideX );
+```
+
+#### stdlib_strided_snansum_ndarray( N, \*X, strideX, offsetX )
+
+Computes the sum of single-precision floating-point strided array elements, ignoring `NaN` values and using alternative indexing semantics.
+
+```c
+const float x[] = { 1.0f, 2.0f, 0.0f/0.0f, 4.0f };
+
+float v = stdlib_strided_snansum_ndarray( 4, x, 1, 0 );
+// returns 7.0f
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] float*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length.
+-   **offsetX**: `[in] CBLAS_INT` starting index.
+
+```c
+float stdlib_strided_snansum_ndarray( const CBLAS_INT N, const float *X, const CBLAS_INT strideX, const CBLAS_INT offsetX );
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- C API usage examples. -->
+
+<section class="examples">
+
+### Examples
+
+```c
+#include "stdlib/blas/ext/base/snansum.h"
+#include <stdio.h>
+
+int main( void ) {
+    // Create a strided array:
+    const float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 0.0f/0.0f, 0.0f/0.0f };
+
+    // Specify the number of elements:
+    const int N = 5;
+
+    // Specify the stride length:
+    const int strideX = 2;
+
+    // Compute the sum:
+    float v = stdlib_strided_snansum( N, x, strideX );
+
+    // Print the result:
+    printf( "Sum: %f\n", v );
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
 <section class="references">
 
 </section>

lib/node_modules/@stdlib/blas/ext/base/snansum/benchmark/benchmark.js

@@ -32,6 +32,19 @@ var snansum = require( './../lib/snansum.js' );
 
 // FUNCTIONS //
 
+/**
+* Returns a random number.
+*
+* @private
+* @returns {number} random number
+*/
+function rand() {
+	if ( bernoulli( 0.5 ) < 1 ) {
+		return uniform( -10.0, 10.0 );
+	}
+	return NaN;
+}
+
 /**
 * Creates a benchmark function.
 *
@@ -43,13 +56,6 @@ function createBenchmark( len ) {
 	var x = filledarrayBy( len, 'float32', rand );
 	return benchmark;
 
-	function rand() {
-		if ( bernoulli( 0.8 ) > 0 ) {
-			return uniform( -10.0, 10.0 );
-		}
-		return NaN;
-	}
-
 	function benchmark( b ) {
 		var v;
 		var i;

lib/node_modules/@stdlib/blas/ext/base/snansum/benchmark/benchmark.native.js

@@ -41,6 +41,19 @@ var opts = {
 
 // FUNCTIONS //
 
+/**
+* Returns a random number.
+*
+* @private
+* @returns {number} random number
+*/
+function rand() {
+	if ( bernoulli( 0.5 ) < 1 ) {
+		return uniform( -10.0, 10.0 );
+	}
+	return NaN;
+}
+
 /**
 * Creates a benchmark function.
 *
@@ -52,13 +65,6 @@ function createBenchmark( len ) {
 	var x = filledarrayBy( len, 'float32', rand );
 	return benchmark;
 
-	function rand() {
-		if ( bernoulli( 0.8 ) > 0 ) {
-			return uniform( -10.0, 10.0 );
-		}
-		return NaN;
-	}
-
 	function benchmark( b ) {
 		var v;
 		var i;

lib/node_modules/@stdlib/blas/ext/base/snansum/benchmark/benchmark.ndarray.js

@@ -32,6 +32,19 @@ var snansum = require( './../lib/ndarray.js' );
 
 // FUNCTIONS //
 
+/**
+* Returns a random number.
+*
+* @private
+* @returns {number} random number
+*/
+function rand() {
+	if ( bernoulli( 0.5 ) < 1 ) {
+		return uniform( -10.0, 10.0 );
+	}
+	return NaN;
+}
+
 /**
 * Creates a benchmark function.
 *
@@ -43,13 +56,6 @@ function createBenchmark( len ) {
 	var x = filledarrayBy( len, 'float32', rand );
 	return benchmark;
 
-	function rand() {
-		if ( bernoulli( 0.8 ) > 0 ) {
-			return uniform( -10.0, 10.0 );
-		}
-		return NaN;
-	}
-
 	function benchmark( b ) {
 		var v;
 		var i;

lib/node_modules/@stdlib/blas/ext/base/snansum/benchmark/benchmark.ndarray.native.js

@@ -41,6 +41,19 @@ var opts = {
 
 // FUNCTIONS //
 
+/**
+* Returns a random number.
+*
+* @private
+* @returns {number} random number
+*/
+function rand() {
+	if ( bernoulli( 0.5 ) < 1 ) {
+		return uniform( -10.0, 10.0 );
+	}
+	return NaN;
+}
+
 /**
 * Creates a benchmark function.
 *
@@ -52,13 +65,6 @@ function createBenchmark( len ) {
 	var x = filledarrayBy( len, 'float32', rand );
 	return benchmark;
 
-	function rand() {
-		if ( bernoulli( 0.8 ) > 0 ) {
-			return uniform( -10.0, 10.0 );
-		}
-		return NaN;
-	}
-
 	function benchmark( b ) {
 		var v;
 		var i;

lib/node_modules/@stdlib/blas/ext/base/snansum/benchmark/c/benchmark.length.c

@@ -94,7 +94,7 @@ 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 ) {
 	double elapsed;
 	float x[ len ];
 	float v;
@@ -111,6 +111,7 @@ static double benchmark( int iterations, int len ) {
 	v = 0.0f;
 	t = tic();
 	for ( i = 0; i < iterations; i++ ) {
+		// cppcheck-suppress uninitvar
 		v = stdlib_strided_snansum( len, x, 1 );
 		if ( v != v ) {
 			printf( "should not return NaN\n" );
@@ -124,6 +125,44 @@ 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;
+	float x[ len ];
+	float v;
+	double t;
+	int i;
+
+	for ( i = 0; i < len; i++ ) {
+		if ( rand_float() < 0.2f ) {
+			x[ i ] = 0.0f / 0.0f; // NaN
+		} else {
+			x[ i ] = ( rand_float()*20000.0f ) - 10000.0f;
+		}
+	}
+	v = 0.0f;
+	t = tic();
+	for ( i = 0; i < iterations; i++ ) {
+		// cppcheck-suppress uninitvar
+		v = stdlib_strided_snansum_ndarray( len, x, 1, 0 );
+		if ( v != v ) {
+			printf( "should not return NaN\n" );
+			break;
+		}
+	}
+	elapsed = tic() - t;
+	if ( v != v ) {
+		printf( "should not return NaN\n" );
+	}
+	return elapsed;
+}
+
 /**
 * Main execution sequence.
 */
@@ -146,7 +185,18 @@ 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 ( i = MIN; i <= MAX; i++ ) {
+		len = pow( 10, i );
+		iter = ITERATIONS / pow( 10, i-1 );
+		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 );
 		}