feat: add C implementation for stats/base/dists/triangular/cdf

PR-URL: #4669
Closes: #4668

Co-authored-by: Philipp Burckhardt <[email protected]>
Reviewed-by: Philipp Burckhardt <[email protected]>
Signed-off-by: Philipp Burckhardt <[email protected]>

Author: 0PrashantYadav0

lib/node_modules/@stdlib/stats/base/dists/triangular/cdf/README.md

@@ -148,6 +148,110 @@ for ( i = 0; i < 25; i++ ) {
 
 <!-- /.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/stats/base/dists/triangular/cdf.h"
+```
+
+#### stdlib_base_dists_triangular_cdf( x, a, b, c )
+
+Evaluates the [cumulative distribution function][cdf] (CDF) for a [triangular][triangular-distribution] distribution with parameters `a` (lower limit), `b` (upper limit) and `c` (mode).
+
+```c
+double y = stdlib_base_dists_triangular_cdf( 0.5, -1.0, 1.0, 0.0 );
+// returns 0.875
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **a**: `[in] double` lower limit.
+-   **b**: `[in] double` upper limit.
+-   **c**: `[in] double` mode.
+
+```c
+double stdlib_base_dists_triangular_cdf( const double x, const double a, const double b, const double c );
+```
+
+</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/stats/base/dists/triangular/cdf.h"
+#include "stdlib/constants/float64/eps.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+
+static double random_uniform( const double min, const double max ) {
+    double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
+    return min + ( v*(max-min) );
+}
+
+int main( void ) {
+    double a;
+    double b;
+    double c;
+    double x;
+    double y;
+    int i;
+
+    for ( i = 0; i < 25; i++ ) {
+        x = random_uniform( 0.0, 30.0 );
+        a = random_uniform( 0.0, 10.0 );
+        b = random_uniform( a, 40.0 ) + STDLIB_CONSTANT_FLOAT64_EPS;
+        c = a + random_uniform( 0.0, b - a );
+        y = stdlib_base_dists_triangular_cdf( x, a, b, c );
+        printf( "x: %lf, a: %lf, b: %lf, c: %lf, F(x;a,b,c): %lf\n", x, a, b, c, 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/stats/base/dists/triangular/cdf/benchmark/benchmark.js

@@ -21,7 +21,8 @@
 // MODULES //
 
 var bench = require( '@stdlib/bench' );
-var randu = require( '@stdlib/random/base/randu' );
+var Float64Array = require( '@stdlib/array/float64' );
+var uniform = require( '@stdlib/random/base/uniform' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var EPS = require( '@stdlib/constants/float64/eps' );
 var pkg = require( './../package.json' ).name;
@@ -34,17 +35,26 @@ bench( pkg, function benchmark( b ) {
 	var mode;
 	var min;
 	var max;
+	var len;
 	var x;
 	var y;
 	var i;
 
+	len = 100;
+	x = new Float64Array( len );
+	min = new Float64Array( len );
+	max = new Float64Array( len );
+	mode = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = uniform( 0.0, 30.0 );
+		min[ i ] = uniform( 0.0, 10.0 );
+		max[ i ] = uniform( min[ i ] + EPS, min[ i ] + 40.0 );
+		mode[ i ] = uniform( min[ i ], max[ i ] );
+	}
+
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		x = randu() * 30.0;
-		min = randu() * 10.0;
-		max = min + ( randu() * 40.0 ) + EPS;
-		mode = min + ( ( max - min ) * randu() );
-		y = cdf( x, min, max, mode );
+		y = cdf( x[ i % len ], min[ i % len ], max[ i % len ], mode[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}
@@ -62,6 +72,7 @@ bench( pkg+':factory', function benchmark( b ) {
 	var mode;
 	var min;
 	var max;
+	var len;
 	var x;
 	var y;
 	var i;
@@ -70,11 +81,15 @@ bench( pkg+':factory', function benchmark( b ) {
 	max = 1.5;
 	mode = 0.5;
 	mycdf = cdf.factory( min, max, mode );
+	len = 100;
+	x = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = uniform( -2.0, 2.0 );
+	}
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		x = ( randu()*2.0 ) - 2.0;
-		y = mycdf( x );
+		y = mycdf( x[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}

lib/node_modules/@stdlib/stats/base/dists/triangular/cdf/benchmark/benchmark.native.js

@@ -0,0 +1,77 @@
+/**
+* @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 Float64Array = require( '@stdlib/array/float64' );
+var uniform = require( '@stdlib/random/base/uniform' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var EPS = require( '@stdlib/constants/float64/eps' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var cdf = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( cdf instanceof Error )
+};
+
+
+// MAIN //
+
+bench( pkg+'::native', opts, function benchmark( b ) {
+	var mode;
+	var min;
+	var max;
+	var len;
+	var x;
+	var y;
+	var i;
+
+	len = 100;
+	x = new Float64Array( len );
+	min = new Float64Array( len );
+	max = new Float64Array( len );
+	mode = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = uniform( 0.0, 30.0 );
+		min[ i ] = uniform( 0.0, 10.0 );
+		max[ i ] = uniform( min[ i ] + EPS, min[ i ] + 40.0 );
+		mode[ i ] = uniform( min[ i ], max[ i ] );
+	}
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = cdf( x[ i%len ], min[ i%len ], max[ i%len ], mode[ i%len ] );
+		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();
+});