feat: add C implementation for math/base/special/heaviside

lib/node_modules/@stdlib/math/base/special/heaviside/README.md

@@ -2,7 +2,7 @@
 
 @license Apache-2.0
 
-Copyright (c) 2018 The Stdlib Authors.
+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.
@@ -164,6 +164,105 @@ logEachMap( 'H(%0.4f) = %0.4f', x, heaviside );
 
 <!-- /.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/math/base/special/heaviside.h"
+```
+
+#### stdlib_base_heaviside( x )
+
+Evaluate the [Heaviside function][heaviside-function].
+
+```c
+double out = stdlib_base_heaviside( 0.0, 0 );
+// returns 0.0
+
+out = stdlib_base_heaviside( 3.141592653589793 / 2.0, 0 );
+// returns 1.0
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **continuity**: `[in] int` input value.
+
+```c
+double stdlib_base_heaviside( const double x, int continuity );
+```
+
+</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/math/base/special/heaviside.h"
+#include <stdio.h>
+
+int main( void ) {
+    const double x[] = { 0.0, -0.523, 0.785, -1.047, 3.14 };
+
+    double y;
+    int i;
+    for ( i = 0; i < 5; i++ ) {
+        y = stdlib_base_heaviside( x[ i ], STDLIB_HEAVISIDE_CONTINUITY_HALF );
+        printf( "heaviside(%lf, half-maximum) = %lf\n", x[ i ], y );
+    }
+
+    for ( i = 0; i < 5; i++ ) {
+        y = stdlib_base_heaviside( x[ i ], STDLIB_HEAVISIDE_CONTINUITY_LEFT );
+        printf( "heaviside(%lf, left-continuous) = %lf\n", x[ i ], y );
+    }
+
+    for ( i = 0; i < 5; i++ ) {
+        y = stdlib_base_heaviside( x[ i ], STDLIB_HEAVISIDE_CONTINUITY_RIGHT );
+        printf( "heaviside(%lf, right-continuous) = %lf\n", x[ i ], y );
+    }
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
 <!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
 
 <section class="related">

lib/node_modules/@stdlib/math/base/special/heaviside/benchmark/benchmark.native.js

@@ -0,0 +1,61 @@
+/**
+* @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 resolve = require( 'path' ).resolve;
+var bench = require( '@stdlib/bench' );
+var uniform = require( '@stdlib/random/array/uniform' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var heaviside = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( heaviside instanceof Error )
+};
+
+
+// MAIN //
+
+bench( pkg+'::native', opts, function benchmark( b ) {
+	var x;
+	var y;
+	var i;
+
+	x = uniform( 100, -10.0, 10.0 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = heaviside( x[ i%x.length ] );
+		if ( isnan( y ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnan( y ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/math/base/special/heaviside/benchmark/c/Makefile

@@ -1,7 +1,7 @@
 #/
 # @license Apache-2.0
 #
-# Copyright (c) 2018 The Stdlib Authors.
+# 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.

lib/node_modules/@stdlib/math/base/special/heaviside/benchmark/c/benchmark.c

@@ -1,7 +1,7 @@
 /**
 * @license Apache-2.0
 *
-* Copyright (c) 2018 The Stdlib Authors.
+* 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.
@@ -21,9 +21,10 @@
 #include <math.h>
 #include <time.h>
 #include <sys/time.h>
+#include "stdlib/math/base/special/heaviside.h"
 
 #define NAME "heaviside"
-#define ITERATIONS 1000000
+#define ITERATIONS 10000
 #define REPEATS 3
 
 /**
@@ -83,25 +84,12 @@ static double rand_double( void ) {
 	return (double)r / ( (double)RAND_MAX + 1.0 );
 }
 
-/**
-* Computes the Heaviside function.
-*
-* @param x   input value
-* @return    function result
-*/
-double heaviside( double x ) {
-	if ( x >= 0.0 ) {
-		return 1.0;
-	}
-	return 0.0;
-}
-
 /**
 * Runs a benchmark.
 *
 * @return elapsed time in seconds
 */
-static double benchmark( void ) {
+static double benchmark( stdlib_heaviside_continuity_t continuity ) {
 	double elapsed;
 	double x[ 100 ];
 	double y;
@@ -114,7 +102,7 @@ static double benchmark( void ) {
 
 	t = tic();
 	for ( i = 0; i < ITERATIONS; i++ ) {
-		y = heaviside( x[ i%100 ] );
+		y = stdlib_base_heaviside( x[ i%100 ], continuity );
 		if ( y != y ) {
 			printf( "should not return NaN\n" );
 			break;
@@ -140,7 +128,23 @@ int main( void ) {
 	print_version();
 	for ( i = 0; i < REPEATS; i++ ) {
 		printf( "# c::%s\n", NAME );
-		elapsed = benchmark();
+		elapsed = benchmark(STDLIB_HEAVISIDE_CONTINUITY_LEFT);
+		print_results( elapsed );
+		printf( "ok %d benchmark finished\n", i+1 );
+	}
+	print_summary( REPEATS, REPEATS );
+
+	for ( i = 0; i < REPEATS; i++ ) {
+		printf( "# c::%s\n", NAME );
+		elapsed = benchmark(STDLIB_HEAVISIDE_CONTINUITY_HALF);
+		print_results( elapsed );
+		printf( "ok %d benchmark finished\n", i+1 );
+	}
+	print_summary( REPEATS, REPEATS );
+
+	for ( i = 0; i < REPEATS; i++ ) {
+		printf( "# c::%s\n", NAME );
+		elapsed = benchmark(STDLIB_HEAVISIDE_CONTINUITY_RIGHT);
 		print_results( elapsed );
 		printf( "ok %d benchmark finished\n", i+1 );
 	}