feat: add implementation for math/base/special/exp10f

[Deepak91168]

Resolves #6711

Description

What is the purpose of this pull request?

This pull request:

• Implements the base-10 exponential function for single-precision floating-point numbers.
• Adds the exp10f package to the @stdlib/math/base/special namespace.
• Includes TypeScript definitions, C implementation, tests, benchmarks, examples, and documentation for the function.

Related Issues

Does this pull request have any related issues?

No

This pull request:

• resolves [RFC]: Add implementation for math/base/special/exp10f #6711

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 TESTS_FILTER=".*/@stdlib/math/base/special/exp10f/.*"
exp10f.test.log

➜ make benchmark-c-files FILES="$(pwd)/lib/node_modules/@stdlib/math/base/special/exp10f/benchmark/c/native/benchmark.c"
exp10f.c_examples.log

➜ make benchmark BENCHMARKS_FILTER=".*/@stdlib/math/base/special/exp10f/.*"
exp10f.benchmark.log

Checklist

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

• Read, understood, and followed the contributing guidelines.

---

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/exp10f	$\color{green}167/167$ $\color{green}+100.00\%$	$\color{green}5/5$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}167/167$ $\color{green}+100.00\%$
math/base/special	$\color{green}2319/2319$ $\color{green}+100.00\%$	$\color{green}1/1$ $\color{green}+100.00\%$	$\color{green}0/0$ $\color{green}+100.00\%$	$\color{green}2319/2319$ $\color{green}+100.00\%$

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

[Deepak91168]

⚠️ Note for reviewers: The CI failure is caused by an unrelated issue in /math/base/special/factorial/benchmark/c/native (missing #include <stdint.h>). This PR does not touch that file.
Please do let me know any changes :)

Workflow link

make[1]: Entering directory '/home/runner/work/stdlib/stdlib/lib/node_modules/@stdlib/math/base/special/factorial/benchmark/c/native'
benchmark.c: In function ‘benchmark’:
benchmark.c:94:9: error: unknown type name ‘int32_t’
   94 |         int32_t x;
      |         ^~~~~~~
benchmark.c:25:1: note: ‘int32_t’ is defined in header ‘<stdint.h>’; did you forget to ‘#include <stdint.h>’?
   24 | #include <sys/time.h>
  +++ |+#include <stdint.h>
   25 | 
benchmark.c:101:22: error: ‘int32_t’ undeclared (first use in this function)
  101 |                 x = (int32_t)floor( 33.0 * rand_double() );
      |                      ^~~~~~~
benchmark.c:101:22: note: ‘int32_t’ is defined in header ‘<stdint.h>’; did you forget to ‘#include <stdint.h>’?
benchmark.c:101:22: note: each undeclared identifier is reported only once for each function it appears in
benchmark.c:101:30: error: expected ‘;’ before ‘floor’
  101 |                 x = (int32_t)floor( 33.0 * rand_double() );
      |                              ^~~~~
      |                              ;
benchmark.c: At top level:
benchmark.c:82:15: warning: ‘rand_double’ defined but not used [-Wunused-function]
   82 | static double rand_double( void ) {
      |               ^~~~~~~~~~~
make[1]: *** [Makefile:124: benchmark.out] Error 1
make[1]: Leaving directory '/home/runner/work/stdlib/stdlib/lib/node_modules/@stdlib/math/base/special/factorial/benchmark/c/native'
Error when attempting to compile benchmark.
ERROR: An error was encountered during execution.

make: *** [/home/runner/work/stdlib/stdlib/tools/make/lib/benchmark/c.mk:84: benchmark-c-files] Error 1

[anandkaranubc]

This is not how we would ideally want the implementation to be. Not quoting anything on how precise/accurate it is. But this implementation is not specific to single-precision floating-point arithmetic.

[anandkaranubc]

Like an example is sin and sinf

https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/sin
https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/sinf

You can notice how different the implementations are, and not a one-to-one port. Hope it helps!

[anandkaranubc]

@Deepak91168 Did you follow any reference implementation for this? It looks like a direct port of exp10, with all the 64-bit types converted to 32-bit ones in the C implementation.

[anandkaranubc]

For the current implementation, I suggest exploring other libraries such as FreeBSD, Cephes, Julia, and Boost to see if they offer a specific single-precision exp10 implementation.

[Deepak91168]

@Deepak91168 Did you follow any reference implementation for this? It looks like a direct port of exp10, with all the 64-bit types converted to 32-bit ones in the C implementation.

Thank you for reviewing! Yes, you're right — this was originally a direct port of the double-precision exp10, and I now understand that this approach doesn’t align with what’s expected. While working on it, I had also looked at the invf implementation, which uses a similar workaround via float math. But I now realize that such techniques aren't appropriate here.

For the current implementation, I suggest exploring other libraries such as FreeBSD, Cephes, Julia, and Boost to see if they offer a specific single-precision exp10 implementation.

I’ve found exp10f implementation provided by Cephes, which follows a proper strategy using argument reduction and polynomial approximation specific to floats:
Cephes Single Precision

Sorry for the earlier oversight — I appreciate your guidance. I’ll now rework the implementation accordingly by refering Cephes closely. Please let me know if this direction sounds good to you, or if there's anything else I should consider.

[anandkaranubc]

@Deepak91168 No worries at all. It's totally fine, and honestly, it's great that you caught this early on. Realising it now saves a lot of effort later, and it's all part of the learning process. Referring to Cephes sounds like a solid plan, especially since it’s tailored for single precision. Let me know if you’d like a second pair of eyes once you’ve made updates. Happy to help!

As a quick sanity check, it might also be helpful to look at another reference implementation and compare it with Cephes. If not, Cephes is definitely a good reference.