feat: add assign and strided methods to csignumf

[Deepak91168]

Resolves #6507

Description

What is the purpose of this pull request?

This pull request: introduces additional functionality and documentation for the @stdlib/math/base/special/csignumf package. Specifically, it:

• Implements two new methods:
  • csignumf.assign(re, im, out, strideOut, offsetOut) for assigning the result of the signum function to an output array.
  • csignumf.strided(z, sz, oz, out, so, oo) for evaluating the signum function on strided array data.
• Adds corresponding test files:
  • test.assign.js
  • test.strided.js
• Adds performance benchmarks:
  • benchmark.assign.js
  • benchmark.strided.js
• Updates the documentation to include usage examples and interface descriptions for the new methods.

Related Issues

No

Does this pull request have any related issues?

This pull request:

• resolves [RFC]: add assign and strided methods to math/base/special/csignumf #6507

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

Output of

➜ make test TEST_FILTER=".*/@stdlib/math/base/special/csignumf.*"

Last Few lines

➜ make benchmark BENCHMARKS_FILTER=".*/@stdlib/math/base/special/csignumf.*"
Click here for complete benchmark.log

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/csignumf	$\color{green}376/376$ $\color{green}+100.00\%$	$\color{green}11/11$ $\color{green}+100.00\%$	$\color{green}4/4$ $\color{green}+100.00\%$	$\color{green}376/376$ $\color{green}+100.00\%$
ndarray/base/zeros	$\color{green}124/124$ $\color{green}+100.00\%$	$\color{green}7/7$ $\color{green}+100.00\%$	$\color{green}1/1$ $\color{green}+100.00\%$	$\color{green}124/124$ $\color{green}+100.00\%$

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