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

PR-URL: #7022
Ref: #649

Co-authored-by: stdlib-bot <[email protected]>
Reviewed-by: Philipp Burckhardt <[email protected]>

Author: anandkaranubc

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

@@ -155,7 +155,7 @@ var heavisidef = require( '@stdlib/math/base/special/heavisidef' );
 var opts = {
     'dtype': 'float32'
 };
-var x = uniform( 101, -10.0, 10.0, opts );
+var x = uniform( 100, -10.0, 10.0, opts );
 
 logEachMap( 'H(%0.4f) = %0.4f', x, heavisidef );
 ```
@@ -164,6 +164,104 @@ logEachMap( 'H(%0.4f) = %0.4f', x, heavisidef );
 
 <!-- /.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/heavisidef.h"
+```
+
+#### stdlib_base_heavisidef( x, continuity )
+
+Evaluates the [Heaviside function][heaviside-function] for a single-precision floating-point number.
+
+```c
+float y = stdlib_base_heavisidef( 0.0f, STDLIB_BASE_HEAVISIDEF_CONTINUITY_HALF_MAXIMUM );
+// returns 0.5f
+
+y = stdlib_base_heavisidef( 0.0f, STDLIB_BASE_HEAVISIDEF_CONTINUITY_LEFT_CONTINUOUS );
+// returns 0.0f
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] float` input value.
+-   **continuity**: `[in] STDLIB_BASE_HEAVISIDEF_CONTINUITY` continuity option.
+
+The `continuity` parameter may be one of the following values:
+
+-   `STDLIB_BASE_HEAVISIDEF_CONTINUITY_HALF_MAXIMUM`: if `x == 0`, the function returns `0.5`.
+-   `STDLIB_BASE_HEAVISIDEF_CONTINUITY_LEFT_CONTINUOUS`: if `x == 0`, the function returns `0.0`.
+-   `STDLIB_BASE_HEAVISIDEF_CONTINUITY_RIGHT_CONTINUOUS`: if `x == 0`, the function returns `1.0`.
+-   `STDLIB_BASE_HEAVISIDEF_CONTINUITY_DISCONTINUOUS`: if `x == 0`, the function returns `NaN`.
+
+If provided a `continuity` argument which is not one of the enumeration constants listed above, the function returns `NaN` for `x == 0`, behaving like the discontinuous case.
+
+```c
+float stdlib_base_heavisidef( const float x, const STDLIB_BASE_HEAVISIDEF_CONTINUITY 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/heavisidef.h"
+#include <stdio.h>
+
+int main( void ) {
+    const float x[] = { -4.0f, -3.0f, -2.0f, -1.0f, 0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
+
+    float y;
+    int i;
+    for ( i = 0; i < 10; i++ ) {
+        y = stdlib_base_heavisidef( x[ i ], STDLIB_BASE_HEAVISIDEF_CONTINUITY_HALF_MAXIMUM );
+        printf( "H(%f) = %f\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/heavisidef/benchmark/benchmark.js

@@ -34,11 +34,13 @@ bench( pkg, function benchmark( b ) {
 	var y;
 	var i;
 
-	x = uniform( 100, -50.0, 50.0 );
+	x = uniform( 100, -50.0, 50.0, {
+		'dtype': 'float32'
+	});
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		y = heavisidef( x[ i % x.length ] );
+		y = heavisidef( x[ i%x.length ] );
 		if ( y > 1.0 ) {
 			b.fail( 'should not return a value greater than 1' );
 		}
@@ -56,11 +58,13 @@ bench( pkg+'::left-continuous', function benchmark( b ) {
 	var y;
 	var i;
 
-	x = uniform( 100, -50.0, 50.0 );
+	x = uniform( 100, -50.0, 50.0, {
+		'dtype': 'float32'
+	});
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		y = heavisidef( x[ i % x.length ], 'left-continuous' );
+		y = heavisidef( x[ i%x.length ], 'left-continuous' );
 		if ( isnanf( y ) ) {
 			b.fail( 'should not return NaN' );
 		}
@@ -78,11 +82,13 @@ bench( pkg+'::right-continuous', function benchmark( b ) {
 	var y;
 	var i;
 
-	x = uniform( 100, -50.0, 50.0 );
+	x = uniform( 100, -50.0, 50.0, {
+		'dtype': 'float32'
+	});
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		y = heavisidef( x[ i % x.length ], 'right-continuous' );
+		y = heavisidef( x[ i%x.length ], 'right-continuous' );
 		if ( isnanf( y ) ) {
 			b.fail( 'should not return NaN' );
 		}
@@ -100,11 +106,13 @@ bench( pkg+'::half-maximum', function benchmark( b ) {
 	var y;
 	var i;
 
-	x = uniform( 100, -50.0, 50.0 );
+	x = uniform( 100, -50.0, 50.0, {
+		'dtype': 'float32'
+	});
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		y = heavisidef( x[ i % x.length ], 'half-maximum' );
+		y = heavisidef( x[ i%x.length ], 'half-maximum' );
 		if ( isnanf( y ) ) {
 			b.fail( 'should not return NaN' );
 		}

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

@@ -0,0 +1,63 @@
+/**
+* @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 isnanf = require( '@stdlib/math/base/assert/is-nanf' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var heavisidef = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( heavisidef instanceof Error )
+};
+
+
+// MAIN //
+
+bench( pkg+'::native', opts, function benchmark( b ) {
+	var x;
+	var y;
+	var i;
+
+	x = uniform( 100, -50.0, 50.0, {
+		'dtype': 'float32'
+	});
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = heavisidef( x[ i%x.length ] );
+		if ( isnanf( y ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnanf( y ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

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

@@ -0,0 +1,127 @@
+#/
+# @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.
+#/
+
+
+# VARIABLES #
+
+ifndef VERBOSE
+	QUIET := @
+else
+	QUIET :=
+endif
+
+# Determine the OS ([1][1], [2][2]).
+#
+# [1]: https://en.wikipedia.org/wiki/Uname#Examples
+# [2]: http://stackoverflow.com/a/27776822/2225624
+OS ?= $(shell uname)
+ifneq (, $(findstring MINGW,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring MSYS,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring CYGWIN,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring Windows_NT,$(OS)))
+	OS := WINNT
+endif
+endif
+endif
+endif
+
+# Define the program used for compiling C source files:
+ifdef C_COMPILER
+	CC := $(C_COMPILER)
+else
+	CC := gcc
+endif
+
+# Define the command-line options when compiling C files:
+CFLAGS ?= \
+	-std=c99 \
+	-O3 \
+	-Wall \
+	-pedantic
+
+# Determine whether to generate position independent code ([1][1], [2][2]).
+#
+# [1]: https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#Code-Gen-Options
+# [2]: http://stackoverflow.com/questions/5311515/gcc-fpic-option
+ifeq ($(OS), WINNT)
+	fPIC ?=
+else
+	fPIC ?= -fPIC
+endif
+
+# List of C targets:
+c_targets := benchmark.out
+
+
+# RULES #
+
+#/
+# Compiles C source files.
+#
+# @param {string} [C_COMPILER] - C compiler
+# @param {string} [CFLAGS] - C compiler flags
+# @param {(string|void)} [fPIC] - compiler flag indicating whether to generate position independent code
+#
+# @example
+# make
+#
+# @example
+# make all
+#/
+all: $(c_targets)
+
+.PHONY: all
+
+#/
+# Compiles C source files.
+#
+# @private
+# @param {string} CC - C compiler
+# @param {string} CFLAGS - C compiler flags
+# @param {(string|void)} fPIC - compiler flag indicating whether to generate position independent code
+#/
+$(c_targets): %.out: %.c
+	$(QUIET) $(CC) $(CFLAGS) $(fPIC) -o $@ $< -lm
+
+#/
+# Runs compiled benchmarks.
+#
+# @example
+# make run
+#/
+run: $(c_targets)
+	$(QUIET) ./$<
+
+.PHONY: run
+
+#/
+# Removes generated files.
+#
+# @example
+# make clean
+#/
+clean:
+	$(QUIET) -rm -f *.o *.out
+
+.PHONY: clean