feat: add implementation of stats/base/dists/halfnormal/logcdf

lib/node_modules/@stdlib/stats/base/dists/halfnormal/logcdf/README.md

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+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2026 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.
+
+-->
+
+# Logarithm of Cumulative Distribution Function
+
+> Evaluate the natural logarithm of the cumulative distribution function (CDF) for a [half-normal][half-normal-distribution] distribution.
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var logcdf = require( '@stdlib/stats/base/dists/halfnormal/logcdf' );
+```
+
+#### logcdf( x, sigma )
+
+Evaluates the natural logarithm of the [cumulative distribution function][cdf] (CDF) for a [half-normal][half-normal-distribution] distribution with parameter `sigma` (standard deviation).
+
+```javascript
+var y = logcdf( 2.0, 1.0 );
+// returns ~-0.0466
+
+y = logcdf( 1.0, 2.0 );
+// returns ~-0.960
+
+```
+
+If provided `NaN` as any argument, the function returns `NaN`.
+
+```javascript
+var y = logcdf( NaN, 1.0 );
+// returns NaN
+
+y = logcdf( 0.0, NaN );
+// returns NaN
+```
+
+If provided `sigma < 0`, the function returns `NaN`.
+
+```javascript
+var y = logcdf( 2.0, -1.0 );
+// returns NaN
+```
+
+If provided `sigma = 0`, the function returns `NaN`.
+
+```javascript
+var y = logcdf( 2.0, 0.0 );
+// returns NaN
+```
+
+#### logcdf.factory( sigma )
+
+Returns a `function` for evaluating the [cumulative distribution function][cdf] (CDF) of a [half-normal][half-normal-distribution] distribution with parameter `sigma` (standard deviation).
+
+```javascript
+var mylogcdf = logcdf.factory( 2.0 );
+
+var y = mylogcdf( 1.0 );
+// returns ~-0.960
+
+y = mylogcdf( 4.0 );
+// returns ~-0.0466
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var uniform = require( '@stdlib/random/array/uniform' );
+var logEachMap = require( '@stdlib/console/log-each-map' );
+var logcdf = require( '@stdlib/stats/base/dists/halfnormal/logcdf' );
+
+var opts = {
+    'dtype': 'float64'
+};
+var sigma = uniform( 10, 0.1, 20.0, opts );
+var x = uniform( 10, 0.0, 10.0, opts );
+
+logEachMap( 'x: %lf, σ: %lf, ln(F(x;σ)): %lf', x, sigma, logcdf );
+```
+
+</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/halfnormal/logcdf.h"
+```
+
+#### stdlib_base_dists_halfnormal_logcdf( x, sigma )
+
+Evaluates the natural logarithm of the [cumulative distribution function][cdf] (CDF) for a [half-normal][half-normal-distribution] distribution with parameter `sigma` (standard deviation).
+
+```c
+double out = stdlib_base_dists_halfnormal_logcdf( 2.0, 1.0 );
+// returns ~-0.046
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **sigma**: `[in] double` standard deviation.
+
+```c
+double stdlib_base_dists_halfnormal_logcdf( const double x, const double sigma );
+```
+
+</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/halfnormal/logcdf.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 sigma;
+     double x;
+     double y;
+     int i;
+
+     for ( i = 0; i < 10; i++ ) {
+          x = random_uniform( 0.0, 10.0 );
+          sigma = random_uniform( 0.1, 20.0 );
+          y = stdlib_base_dists_halfnormal_logcdf( x, sigma );
+          printf( "x: %lf, σ: %lf, ln(F(x;σ)): %lf\n", x, sigma, y );
+     }
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="links">
+
+[cdf]: https://en.wikipedia.org/wiki/Cumulative_distribution_function
+
+[half-normal-distribution]: https://en.wikipedia.org/wiki/Half-normal_distribution
+
+</section>
+
+<!-- /.links -->
+

lib/node_modules/@stdlib/stats/base/dists/halfnormal/logcdf/benchmark/benchmark.js

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+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 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 uniform = require( '@stdlib/random/array/uniform' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var EPS = require( '@stdlib/constants/float64/eps' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var logcdf = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var sigma;
+	var len;
+	var x;
+	var y;
+	var i;
+
+	len = 100;
+	x = uniform( len, -10.0, 10.0 );
+	sigma = uniform( len, EPS, 20.0 + EPS );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = logcdf( x[ i % len ], sigma[ 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( format( '%s::factory', pkg ), function benchmark( b ) {
+	var mylogcdf;
+	var sigma;
+	var x;
+	var y;
+	var i;
+
+	sigma = 1.5;
+	mylogcdf = logcdf.factory( sigma );
+	x = uniform( 100, -3.0, 6.0 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = mylogcdf( 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/stats/base/dists/halfnormal/logcdf/benchmark/benchmark.native.js

@@ -0,0 +1,68 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 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 EPS = require( '@stdlib/constants/float64/eps' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var logcdf = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( logcdf instanceof Error )
+};
+
+
+// MAIN //
+
+bench( format( '%s::native', pkg ), opts, function benchmark( b ) {
+	var sigma;
+	var len;
+	var x;
+	var y;
+	var i;
+
+	len = 100;
+	x = uniform( len, -10.0, 10.0 );
+	sigma = uniform( len, EPS, 20.0 + EPS );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		y = logcdf( x[ i % len ], sigma[ 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();
+});