feat(negative-binomial-variance): adding code required for negative binomial variance

Author: Aadish Jain

lib/node_modules/@stdlib/math/base/napi/binary/include/stdlib/math/base/napi/binary.h

@@ -616,6 +616,48 @@
 	};                                                                         \
 	NAPI_MODULE( NODE_GYP_MODULE_NAME, stdlib_math_base_napi_ll_d_init )
 
+/**
+* Macro for registering a Node-API module exporting an interface invoking a binary function accepting signed 64-bit integers and a double-precision floating-point and returning a double-precision floating-point number.
+*
+* @param fcn   binary function
+*
+* @example
+* #include <stdint.h>
+*
+* static double fcn( const int_64 x, const double y ) {
+*     // ...
+* }
+*
+* // ...
+*
+* // Register a Node-API module:
+* STDLIB_MATH_BASE_NAPI_MODULE_LD_D( fcn );
+*/
+#define STDLIB_MATH_BASE_NAPI_MODULE_LD_D( fcn )                               \
+	static napi_value stdlib_math_base_napi_ld_d_wrapper(                      \
+		napi_env env,                                                          \
+		napi_callback_info info                                                \
+	) {                                                                        \
+		return stdlib_math_base_napi_ld_d( env, info, fcn );                   \
+	};                                                                         \
+	static napi_value stdlib_math_base_napi_ld_d_init(                         \
+		napi_env env,                                                          \
+		napi_value exports                                                     \
+	) {                                                                        \
+		napi_value fcn;                                                        \
+		napi_status status = napi_create_function(                             \
+			env,                                                               \
+			"exports",                                                         \
+			NAPI_AUTO_LENGTH,                                                  \
+			stdlib_math_base_napi_ld_d_wrapper,                                \
+			NULL,                                                              \
+			&fcn                                                               \
+		);                                                                     \
+		assert( status == napi_ok );                                           \
+		return fcn;                                                            \
+	};                                                                         \
+	NAPI_MODULE( NODE_GYP_MODULE_NAME, stdlib_math_base_napi_ld_d_init )
+
 /**
 * Macro for registering a Node-API module exporting an interface invoking a binary function accepting signed 32-bit integers and returning a single-precision floating-point number.
 *
@@ -730,6 +772,11 @@ napi_value stdlib_math_base_napi_cf_c( napi_env env, napi_callback_info info, st
 */
 napi_value stdlib_math_base_napi_ll_d( napi_env env, napi_callback_info info, double (*fcn)( int64_t, int64_t ) );
 
+/**
+* Invokes a binary function accepting a signed 64-bit integer and a double-precision floating-point number and returning a double-precision floating-point number.
+*/
+napi_value stdlib_math_base_napi_ld_d( napi_env env, napi_callback_info info, double (*fcn)( int64_t, double ) );
+
 /**
 * Invokes a binary function accepting signed 32-bit integers and returning a single-precision floating-point number.
 */

lib/node_modules/@stdlib/math/base/napi/binary/src/main.c

@@ -87,6 +87,67 @@ napi_value stdlib_math_base_napi_dd_d( napi_env env, napi_callback_info info, do
 
 	return v;
 }
+/**
+* Invokes a binary function accepting a signed 64-bit integer and a double-precision floating-point number and returning double-precision floating-point numbers.
+*
+* ## Notes
+*
+* -   This function expects that the callback `info` argument provides access to the following JavaScript arguments:
+*
+*     -   `x`: input value.
+*     -   `y`: input value.
+*
+* @param env    environment under which the function is invoked
+* @param info   callback data
+* @param fcn    binary function
+* @return       function return value as a Node-API double-precision floating-point number
+*/
+napi_value stdlib_math_base_napi_ld_d( napi_env env, napi_callback_info info, double (*fcn)( int64_t, double ) ) {
+	napi_status status;
+
+	size_t argc = 2;
+	napi_value argv[ 2 ];
+	status = napi_get_cb_info( env, info, &argc, argv, NULL, NULL );
+	assert( status == napi_ok );
+
+	if ( argc < 2 ) {
+		status = napi_throw_error( env, NULL, "invalid invocation. Must provide two numbers." );
+		assert( status == napi_ok );
+		return NULL;
+	}
+
+	napi_valuetype vtype0;
+	status = napi_typeof( env, argv[ 0 ], &vtype0 );
+	assert( status == napi_ok );
+	if ( vtype0 != napi_number ) {
+		status = napi_throw_type_error( env, NULL, "invalid argument. First argument must be a number." );
+		assert( status == napi_ok );
+		return NULL;
+	}
+
+	napi_valuetype vtype1;
+	status = napi_typeof( env, argv[ 1 ], &vtype1 );
+	assert( status == napi_ok );
+	if ( vtype1 != napi_number ) {
+		status = napi_throw_type_error( env, NULL, "invalid argument. Second argument must be a number." );
+		assert( status == napi_ok );
+		return NULL;
+	}
+
+	int64_t x;
+	status = napi_get_value_int64( env, argv[ 0 ], &x );
+	assert( status == napi_ok );
+
+	double y;
+	status = napi_get_value_double( env, argv[ 1 ], &y );
+	assert( status == napi_ok );
+
+	napi_value v;
+	status = napi_create_double( env, fcn( x, y ), &v );
+	assert( status == napi_ok );
+
+	return v;
+}
 
 /**
 * Invokes a binary function accepting and returning single-precision floating-point numbers.

lib/node_modules/@stdlib/stats/base/dists/negative-binomial/variance/README.md

@@ -137,6 +137,103 @@ 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/negative-binomial/variance.h"
+```
+
+#### stdlib_base_dists_negative_binomial_variance( r, p )
+
+Returns the variance of a negative binomial distribution with parameters `r` (number of successes until experiment is stopped) and `p` (success probability).
+
+```c
+double v = stdlib_base_dists_negative_binomial_variance( 100, 0.2 );
+// returns ~2000.0
+```
+
+The function accepts the following arguments:
+
+-   **r**: `[in] int` number of successes until experiment is stopped.
+-   **p**: `[in] double` success probability.
+
+```c
+double stdlib_base_dists_negative_binomial_variance( const int64_t r, const double p );
+```
+
+</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/negative-binomial/variance.h"
+#include <stdlib.h>
+#include <stdint.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 ) {
+    int64_t r;
+    double p;
+    double v;
+    int i;
+
+
+    for ( i = 0; i < 10; i++ ) {
+        r = (int64_t)random_uniform( -1.0, 100.0 );
+        p = random_uniform( 0.0, 1.0 );
+        v = stdlib_base_dists_negative_binomial_variance( r, p );
+        printf( "r: %ld, p: %lf, Var(X;r,p): %lf\n", r, p, v );
+    }
+}
+```
+
+</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">

lib/node_modules/@stdlib/stats/base/dists/negative-binomial/variance/benchmark/benchmark.js

@@ -21,35 +21,70 @@
 // MODULES //
 
 var bench = require( '@stdlib/bench' );
-var ceil = require( '@stdlib/math/base/special/ceil' );
+var Float64Array = require( '@stdlib/array/float64' );
+var uniform = require( '@stdlib/random/array/uniform' );
 var randu = require( '@stdlib/random/base/randu' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
-var EPS = require( '@stdlib/constants/float64/eps' );
+var floor = require( '@stdlib/math/base/special/floor' );
 var pkg = require( './../package.json' ).name;
 var variance = require( './../lib' );
 
 
 // MAIN //
 
-bench( pkg, function benchmark( b ) {
+bench(pkg, function benchmark(b) {
+	var len;
 	var r;
 	var p;
 	var y;
 	var i;
 
+	len = 100;
+	r = new Float64Array(len);
+	p = new Float64Array(len);
+	for (i = 0; i < len; i++) {
+		r[i] = floor((randu() * 10.0) + 1.0); // Treat r as int64_t
+		p[i] = (randu() * 0.8) + 0.1;
+	}
+
+	b.tic();
+	for (i = 0; i < b.iterations; i++) {
+		y = variance(r[i % len], p[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 myvariance;
+	var r;
+	var p;
+	var y;
+	var i;
+	var x = uniform(100, 1.0, 10.0);
+
+	r = 5;
+	p = 0.5;
+	myvariance = variance.factory(r, p);
+
 	b.tic();
-	for ( i = 0; i < b.iterations; i++ ) {
-		r = ceil( randu()*100.0 );
-		p = ( randu()*1.0 ) + EPS;
-		y = variance( r, p );
-		if ( isnan( y ) ) {
-			b.fail( 'should not return NaN' );
+	for (i = 0; i < b.iterations; i++) {
+		y = myvariance(x[i % x.length]);
+		if (isnan(y)) {
+			b.fail('should not return NaN');
 		}
 	}
 	b.toc();
-	if ( isnan( y ) ) {
-		b.fail( 'should not return NaN' );
+	if (isnan(y)) {
+		b.fail('should not return NaN');
 	}
-	b.pass( 'benchmark finished' );
+	b.pass('benchmark finished');
 	b.end();
 });

lib/node_modules/@stdlib/stats/base/dists/negative-binomial/variance/benchmark/benchmark.native.js

@@ -0,0 +1,71 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 randu = require( '@stdlib/random/base/randu' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var floor = require( '@stdlib/math/base/special/floor' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var variance = tryRequire(resolve(__dirname, './../lib/native.js'));
+var opts = {
+	'skip': (variance instanceof Error)
+};
+
+
+// MAIN //
+
+bench(pkg + '::native', opts, function benchmark(b) {
+	var len;
+	var r;
+	var p;
+	var y;
+	var i;
+
+	len = 100;
+	r = new Float64Array(len);
+	p = new Float64Array(len);
+	for (i = 0; i < len; i++) {
+		r[i] = floor((randu() * 10.0) + 1.0);
+		p[i] = (randu() * 0.8) + 0.1;
+	}
+
+	b.tic();
+	for (i = 0; i < b.iterations; i++) {
+		y = variance(r[i % len], p[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();
+});