feat: add stats/base/dists/planck/mean

lib/node_modules/@stdlib/stats/base/dists/planck/mean/README.md

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+<!--
+
+@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.
+
+-->
+
+# Mean
+
+> Planck distribution [expected value][expected-value].
+
+<!-- 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">
+
+The [expected value][expected-value] for a geometric random variable is
+
+<!-- <equation class="equation" label="eq:planck_expectation" align="center" raw="\mathbb{E}\left[ X \right] = \frac{1}{e^{\lambda} - 1}" alt="Expected value for a Planck distribution."> -->
+
+```math
+\mathbb{E}\left[ X \right] = \frac{1}{e^{\lambda} - 1}
+```
+
+<!-- </equation> -->
+
+where `lambda` is the shape parameter.
+
+</section>
+
+<!-- /.intro -->
+
+<!-- Package usage documentation. -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var mean = require( '@stdlib/stats/base/dists/planck/mean' );
+```
+
+#### mean( lambda )
+
+Returns the [expected value][expected-value] of a planck distribution with shape parameter `lambda`.
+
+```javascript
+var v = mean( 0.1 );
+// returns ~9.5083
+
+v = mean( 0.5 );
+// returns ~1.5415
+```
+
+If provided a shape parameter `lambda` which is negative or `NaN`, the function returns `NaN`.
+
+```javascript
+var v = mean( NaN );
+// returns NaN
+
+v = mean( -1.5 );
+// returns NaN
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- Package usage examples. -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var randu = require( '@stdlib/random/base/randu' );
+var mean = require( '@stdlib/stats/base/dists/planck/mean' );
+
+var lambda;
+var v;
+var i;
+
+for ( i = 0; i < 10; i++ ) {
+    lambda = randu();
+    v = mean( lambda );
+    console.log( 'lambda: %d, E(X;lambda): %d', lambda.toFixed( 4 ), v.toFixed( 4 ) );
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- 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">
+
+</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">
+
+[expected-value]: https://en.wikipedia.org/wiki/Expected_value
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/stats/base/dists/planck/mean/benchmark/benchmark.js

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+/**
+* @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 bench = require( '@stdlib/bench' );
+var randu = require( '@stdlib/random/base/randu' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var EPS = require( '@stdlib/constants/float64/eps' );
+var pkg = require( './../package.json' ).name;
+var mean = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var lambda;
+	var y;
+	var i;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		lambda = ( randu()*20.0 ) + EPS;
+		y = mean( lambda );
+		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/planck/mean/docs/repl.txt

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+
+{{alias}}( lambda )
+    Returns the expected value of a planck distribution with shape
+    parameter `lambda`.
+
+    If `lambda < 0`, the function returns `NaN`.
+
+    Parameters
+    ----------
+    lambda: number
+        Shape parameter.
+
+    Returns
+    -------
+    out: number
+        Expected value.
+
+    Examples
+    --------
+    > var v = {{alias}}( 0.1 )
+    ~9.5083
+    > v = {{alias}}( 0.5 )
+    ~1.5415
+
+    See Also
+    --------
+

lib/node_modules/@stdlib/stats/base/dists/planck/mean/docs/types/index.d.ts

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+/*
+* @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.
+*/
+
+// TypeScript Version: 4.1
+
+/**
+* Returns the expected value of a planck distribution.
+*
+* ## Notes
+*
+* -   If `lambda < 0`, the function returns `NaN`.
+*
+* @param lambda - shape parameter
+* @returns expected value
+*
+* @example
+* var v = mean( 0.1 );
+* // returns ~9.5083
+*
+* @example
+* var v = mean( 0.5 );
+* // returns ~1.5415
+*
+* @example
+* var v = mean( 1.1 );
+* // returns ~0.4989
+*
+* @example
+* var v = mean( NaN );
+* // returns NaN
+*/
+declare function mean( lambda: number ): number;
+
+
+// EXPORTS //
+
+export = mean;

lib/node_modules/@stdlib/stats/base/dists/planck/mean/docs/types/test.ts

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+/*
+* @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.
+*/
+
+import mean = require( './index' );
+
+
+// TESTS //
+
+// The function returns a number...
+{
+	mean( 0.3 ); // $ExpectType number
+}
+
+// The compiler throws an error if the function is provided a value other than a number...
+{
+	mean( true ); // $ExpectError
+	mean( false ); // $ExpectError
+	mean( null ); // $ExpectError
+	mean( undefined ); // $ExpectError
+	mean( '5' ); // $ExpectError
+	mean( [] ); // $ExpectError
+	mean( {} ); // $ExpectError
+	mean( ( x: number ): number => x ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided insufficient arguments...
+{
+	mean(); // $ExpectError
+}

lib/node_modules/@stdlib/stats/base/dists/planck/mean/examples/index.js

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+/**
+* @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';
+
+var randu = require( '@stdlib/random/base/randu' );
+var mean = require( './../lib' );
+
+var lambda;
+var v;
+var i;
+
+for ( i = 0; i < 10; i++ ) {
+	lambda = randu();
+	v = mean( lambda );
+	console.log( 'lambda: %d, E(X;lambda): %d', lambda.toFixed( 4 ), v.toFixed( 4 ) );
+}

lib/node_modules/@stdlib/stats/base/dists/planck/mean/lib/index.js

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+/**
+* @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';
+
+/**
+* Planck distribution expected value.
+*
+* @module @stdlib/stats/base/dists/planck/mean
+*
+* @example
+* var mean = require( '@stdlib/stats/base/dists/planck/mean' );
+*
+* var v = mean( 0.1 );
+* // returns ~9.5083
+*
+* v = mean( 0.5 );
+* // returns ~1.5415
+*/
+
+// MODULES //
+
+var mean = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = mean;