feat: add Wald distribution mean package #9502

manit2004 · 2026-01-02T13:11:36Z

Progresses #209

Description

This is a WIP pull request. Currently the core functionalities of Wald Distribution mean package has been implemented. Feedback needed on this implementation.

Tests, docs, examples and benchmark is yet to added, pending approval of the core implementation.

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This pull request has the following related issues:

RFC: add the Wald distribution #209

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I have used this Wiki page as a reference.

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Read, understood, and followed the contributing guidelines.

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Planeshifter · 2026-01-04T06:42:09Z

lib/node_modules/@stdlib/stats/base/dists/wald/mean/lib/main.js

+* @example
+* var y = mean( 0.0, 1.0 );
+* // returns NaN
+*
+* @example
+* var y = mean( 1.0, 0.0 );
+* // returns NaN


First examples should always showcase valid inputs (this is something that should be addressed in various files).

Planeshifter · 2026-01-04T06:42:42Z

lib/node_modules/@stdlib/stats/base/dists/wald/mean/lib/main.js

+// MAIN //
+
+/**
+* Returns the expected value for a wald distribution with mean `mu` and standard deviation `sigma`.


Suggested change

* Returns the expected value for a wald distribution with mean `mu` and standard deviation `sigma`.

* Returns the expected value for a Wald distribution with mean `mu` and standard deviation `sigma`.

Planeshifter · 2026-01-04T06:44:13Z

lib/node_modules/@stdlib/stats/base/dists/wald/mean/lib/native.js

+// MAIN //
+
+/**
+* Evaluates the expected value for a Wald distribution with mean `mu` and standard deviation `sigma`.


Suggested change

* Evaluates the expected value for a Wald distribution with mean `mu` and standard deviation `sigma`.

* Returns the expected value for a Wald distribution with mean `mu` and standard deviation `sigma`.

Planeshifter

As in #9324, the Wald distribution has a second shape parameter lambda and not standard deviation sigma, so this will have to be updated across this PR.

stdlib-bot · 2026-01-04T13:45:51Z

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/wald/mean	$\color{green}184/184$ $\color{green}+0.00%$	$\color{green}10/10$ $\color{green}+0.00%$	$\color{green}2/2$ $\color{green}+0.00%$	$\color{green}184/184$ $\color{green}+0.00%$

The above coverage report was generated for the changes in this PR.

Planeshifter

Thanks for the edits!

The PR is currently missing README.md, benchmarks, and also contains extraneous changes to normal/mean that should be reverted.

lib/node_modules/@stdlib/stats/base/dists/wald/mean/docs/repl.txt

lib/node_modules/@stdlib/stats/base/dists/wald/mean/src/main.c

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

Signed-off-by: Philipp Burckhardt <[email protected]>

Planeshifter · 2026-01-07T04:33:32Z

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

+* y = mean( 4.0, 2.0 );
+* // returns 4.0
+*
+* var y = mean( 0.0, 1.0 );


Suggested change

* y = mean( 4.0, 2.0 );

* // returns 4.0

*

* var y = mean( 0.0, 1.0 );

* var y = mean( 4.0, 2.0 );

* // returns 4.0

*

* y = mean( 0.0, 1.0 );

Planeshifter · 2026-01-07T04:34:40Z

lib/node_modules/@stdlib/stats/base/dists/wald/mean/docs/repl.txt

+    > y = {{alias}}( 4.0, 2.0 )
+    4.0
+    > var y = {{alias}}( 0.0, 1.0 )
+    NaN
+    > var y = {{alias}}( 1.0, 0.0 )
+    NaN


Suggested change

> y = {{alias}}( 4.0, 2.0 )

4.0

> var y = {{alias}}( 0.0, 1.0 )

NaN

> var y = {{alias}}( 1.0, 0.0 )

NaN

> var y = {{alias}}( 4.0, 2.0 )

4.0

> y = {{alias}}( 0.0, 1.0 )

NaN

> y = {{alias}}( 1.0, 0.0 )

NaN

Planeshifter · 2026-01-07T04:36:52Z

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

+
+<section class="intro">
+
+The [expected value][mean] for a [wald][wald-distribution] random variable with mean `μ` and shape parameter `λ > 0` is


Since the distribution is named after a person, Abraham Wald, we should capitalize it here and elsewhere and use "Wald distribution".

Planeshifter · 2026-01-07T04:38:09Z

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

+
+The [expected value][mean] for a [wald][wald-distribution] random variable with mean `μ` and shape parameter `λ > 0` is
+
+<!-- <equation class="equation" label="eq:wald_expectation" align="center" raw="\mathbb{E}\left[ X \right] = \mu" alt="Expected value for a normal distribution."> -->


Incorrectly referring to normal distribution here and below.

Planeshifter · 2026-01-07T04:39:09Z

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

+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		mu = ( randu()*100.0 ) + EPS;


Let's update the benchmark files to use the random array functions like in the example code to move the random number generation out of the benchmarking loop.

Consult other stats packages for how this should look these days.

Planeshifter · 2026-01-07T04:40:55Z

lib/node_modules/@stdlib/stats/base/dists/wald/mean/examples/c/example.c

+#ifndef STDLIB_CONSTANT_FLOAT64_EPS
+#define STDLIB_CONSTANT_FLOAT64_EPS 2.22044604925031308e-16
+#endif


Not needed; let's just use the same example as in the README.md and use 0.1 instead of STDLIB_CONSTANT_FLOAT64_EPS for the minimum value. In general, the example block in the README.md should match what is in the example files.

Planeshifter

Left a bunch more comments.

lib/node_modules/@stdlib/stats/base/dists/wald/mean/docs/repl.txt

Signed-off-by: Philipp Burckhardt <[email protected]>

Planeshifter

LGTM! Thanks for cleaning the PR up and getting it into a good shape!

stdlib-bot · 2026-01-07T19:42:40Z

PR Commit Message

feat: add Wald distribution mean package

PR-URL: https://github.com/stdlib-js/stdlib/pull/9502
Closes: https://github.com/stdlib-js/stdlib/issues/209

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

Please review the above commit message and make any necessary adjustments.

mean package core implemented

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	* Returns the expected value for a wald distribution with mean `mu` and standard deviation `sigma`.
	* Returns the expected value for a Wald distribution with mean `mu` and standard deviation `sigma`.

	* Evaluates the expected value for a Wald distribution with mean `mu` and standard deviation `sigma`.
	* Returns the expected value for a Wald distribution with mean `mu` and standard deviation `sigma`.


		<section class="intro">

		The [expected value][mean] for a [wald][wald-distribution] random variable with mean `μ` and shape parameter `λ > 0` is


		The [expected value][mean] for a [wald][wald-distribution] random variable with mean `μ` and shape parameter `λ > 0` is

		<!-- <equation class="equation" label="eq:wald_expectation" align="center" raw="\mathbb{E}\left[ X \right] = \mu" alt="Expected value for a normal distribution."> -->

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feat: add Wald distribution mean package #9502

feat: add Wald distribution mean package #9502

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