feat: add C implementation for stats/base/dists/discrete-uniform/logcdf

PR-URL: #4644
Closes: #3552

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

Author: 0PrashantYadav0

lib/node_modules/@stdlib/stats/base/dists/discrete-uniform/logcdf/README.md

@@ -122,31 +122,136 @@ y = myLogCDF( 8.0 );
 <!-- eslint no-undef: "error" -->
 
 ```javascript
-var randint = require( '@stdlib/random/base/discrete-uniform' );
-var randu = require( '@stdlib/random/base/randu' );
+var uniform = require( '@stdlib/random/array/uniform' );
+var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
 var logcdf = require( '@stdlib/stats/base/dists/discrete-uniform/logcdf' );
 
-var randa = randint.factory( 0, 10 );
-var randb = randint.factory();
+var x;
 var a;
 var b;
-var x;
 var v;
 var i;
 
-for ( i = 0; i < 10; i++ ) {
-    x = randu() * 15.0;
-    a = randa();
-    b = randb( a, a+randa() );
-    v = logcdf( x, a, b );
-    console.log( 'x: %d, a: %d, b: %d, ln(F(x;a,b)): %d', x.toFixed( 4 ), a.toFixed( 4 ), b.toFixed( 4 ), v.toFixed( 4 ) );
+x = uniform( 10, -10.0, 10.0 );
+a = discreteUniform( 10, -10, 0 );
+b = discreteUniform( 10, 0, 10 );
+
+for ( i = 0; i < x.length; i++ ) {
+    v = logcdf( x[ i ], a[ i ], b[ i ] );
+    console.log( 'x: %d, a: %d, b: %d, ln(F(x;a,b)): %d', x[ i ].toFixed( 4 ), a[ i ], b[ i ], v.toFixed( 4 ) );
+}
+```
+
+</section>
+
+<!-- /.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/discrete-uniform/logcdf.h"
+```
+
+#### stdlib_base_dists_discrete_uniform_logcdf( x, a, b )
+
+Evaluates the natural logarithm of the [cumulative distribution function][cdf] (CDF) for a [discrete uniform][discrete-uniform-distribution] distribution with parameters `a` (minimum support) and `b` (maximum support).
+
+```c
+double out = stdlib_base_dists_discrete_uniform_logcdf( 9.0, 0, 10 );
+// returns ~-0.095
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **a**: `[in] int32_t` minimum support.
+-   **b**: `[in] int32_t` maximum support.
+
+```c
+double stdlib_base_dists_discrete_uniform_logcdf( const double x, const int32_t a, const int32_t b );
+```
+
+</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/discrete-uniform/logcdf.h"
+#include "stdlib/math/base/special/round.h"
+#include <stdint.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 ) {
+    int32_t a;
+    int32_t b;
+    double x;
+    double y;
+    int i;
+
+    for ( i = 0; i < 10; i++ ) {
+        x = random_uniform( -10.0, 10.0 );
+        a = stdlib_base_round( random_uniform( 0.0, 5.0 ) );
+        b = stdlib_base_round( random_uniform( a, a + 5.0 ) );
+        y = stdlib_base_dists_discrete_uniform_logcdf( x, a, b );
+        printf( "x:%lf, a: %d, b: %d, ln(F(X;a,b)): %lf\n", x, a, b, y );
+    }
 }
 ```
 
 </section>
 
 <!-- /.examples -->
 
+</section>
+
+<!-- /.c -->
+
+<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="references">
+
+</section>
+
+<!-- /.references -->
+
 <!-- 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/discrete-uniform/logcdf/benchmark/benchmark.js

@@ -21,9 +21,8 @@
 // MODULES //
 
 var bench = require( '@stdlib/bench' );
-var Float64Array = require( '@stdlib/array/float64' );
-var uniform = require( '@stdlib/random/base/uniform' );
-var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
+var uniform = require( '@stdlib/random/array/uniform' );
+var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var pkg = require( './../package.json' ).name;
 var logcdf = require( './../lib' );
@@ -40,14 +39,9 @@ bench( pkg, function benchmark( b ) {
 	var i;
 
 	len = 100;
-	x = new Float64Array( len );
-	min = new Float64Array( len );
-	max = new Float64Array( len );
-	for ( i = 0; i < len; i++ ) {
-		x[ i ] = uniform( -10.0, 10.0 );
-		min[ i ] = discreteUniform( -20, 0 );
-		max[ i ] = discreteUniform( min[ i ], min[ i ] + 40 );
-	}
+	x = uniform( len, -10.0, 10.0 );
+	min = discreteUniform( len, -10, 0 );
+	max = discreteUniform( len, 0, 10 );
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
@@ -77,10 +71,7 @@ bench( pkg+':factory', function benchmark( b ) {
 	max = 2;
 	mylogcdf = logcdf.factory( min, max );
 	len = 100;
-	x = new Float64Array( len );
-	for ( i = 0; i < len; i++ ) {
-		x[ i ] = uniform( -2.0, 0.0 );
-	}
+	x = uniform( len, -2.0, 0.0 );
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {

lib/node_modules/@stdlib/stats/base/dists/discrete-uniform/logcdf/benchmark/benchmark.native.js

@@ -0,0 +1,67 @@
+/**
+* @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 logcdf = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( logcdf instanceof Error )
+};
+
+
+// MAIN //
+
+bench( pkg+'::native', opts, function benchmark( b ) {
+	var min;
+	var max;
+	var len;
+	var x;
+	var y;
+	var i;
+
+	len = 100;
+	x = uniform( len, -10.0, 10.0 );
+	min = uniform( len, -10.0, 0.0 );
+	max = uniform( len, 0.0, 10.0 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = logcdf( x[ i % len ], min[ i % len ], max[ 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();
+});