feat: add c implementation for stats/base/dists/signrank/pdf

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Author: Lokeshranjan8

lib/node_modules/@stdlib/stats/base/dists/signrank/pdf/README.md

@@ -126,6 +126,102 @@ for ( i = 0; i < 10; 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/signrank/pdf.h"
+```
+
+#### stdlib_base_dists_signrank_cdf( x, n )
+
+Evaluates the probability density function (PDF) of the Wilcoxon signed rank test statistic with `n` observations.
+
+```c
+double out = stdlib_base_dists_signrank_pdf( 7.0, 9 );
+// returns ~0.01
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **n**: `[in] double` number of observations.
+
+```c
+double stdlib_base_dists_signrank_cdf( double x, const double n );
+```
+
+</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/signrank/pdf.h"
+#include "stdlib/math/base/special/ceil.h"
+#include <stdlib.h>
+#include <stdio.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 n;
+    double x;
+    double y;
+    int i;
+
+    for ( i = 0; i < 25; i++ ) {
+        x = random_uniform( 0, 30.0 );
+        n = stdlib_base_ceil(random_uniform( 1, 30.0 ));
+        y = stdlib_base_dists_signrank_pdf( x, n );
+        printf( "x: %lf, n: %lf, F(x;n): %lf\n", x, n, 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/signrank/pdf/benchmark/benchmark.js

@@ -20,53 +20,44 @@
 
 // MODULES //
 
+var resolve = require( 'path' ).resolve;
 var bench = require( '@stdlib/bench' );
+var Float64Array = require( '@stdlib/array/float64' );
 var randu = require( '@stdlib/random/base/randu' );
 var ceil = require( '@stdlib/math/base/special/ceil' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var tryRequire = require( '@stdlib/utils/try-require' );
 var pkg = require( './../package.json' ).name;
-var pdf = require( './../lib' );
 
 
-// MAIN //
+// VARIABLES //
 
-bench( pkg, function benchmark( b ) {
-	var n;
-	var x;
-	var y;
-	var i;
+var pdf = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( pdf instanceof Error )
+};
 
-	b.tic();
-	for ( i = 0; i < b.iterations; i++ ) {
-		x = randu() * 20.0;
-		n = ceil( randu()*20.0 );
-		y = pdf( x, n );
-		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();
-});
 
-bench( pkg+':factory', function benchmark( b ) {
-	var mypdf;
+// MAIN //
+
+bench( pkg, opts, function benchmark( b ) {
+	var len;
 	var n;
 	var x;
 	var y;
 	var i;
 
-	n = 20;
-	mypdf = pdf.factory( n );
+	len = 100;
+	x = new Float64Array( len );
+	n = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = ( randu() * 30.0 );
+		n[ i ] = ceil( randu() * 30.0 );
+	}
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		x = randu() * 20.0;
-		y = mypdf( x );
+		y = pdf( x[ i % len ], n[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}

lib/node_modules/@stdlib/stats/base/dists/signrank/pdf/benchmark/benchmark.native.js

@@ -0,0 +1,89 @@
+/**
+* @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 bench = require( '@stdlib/bench' );
+var Float64Array = require( '@stdlib/array/float64' );
+var uniform = require( '@stdlib/random/array/uniform' );
+var randu = require( '@stdlib/random/base/randu' );
+var ceil = require( '@stdlib/math/base/special/ceil' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var pkg = require( './../package.json' ).name;
+var pdf = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var len;
+	var n;
+	var x;
+	var y;
+	var i;
+
+	len = 100;
+	x = new Float64Array( len );
+	n = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = ( randu() * 30.0 );
+		n[ i ] = ceil( randu() * 30.0 );
+	}
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = pdf( x[ i % len ], n[ 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();
+});
+
+bench( pkg+':factory', function benchmark( b ) {
+	var mypdf;
+	var n;
+	var x;
+	var y;
+	var i;
+
+	n = 20;
+	mypdf = pdf.factory( n );
+	x = uniform( 100, -2.0, 2.0 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = mypdf( 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();
+});