Add additional float constants

[ghost]

Initial implementation of this ACP: rust-lang/libs-team#119. [Accepted]
Tracking issue: #103883

The values for the constants are copied from the libstdc++ source code.

[rustbot]

r? @joshtriplett

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[rustbot]

Hey! It looks like you've submitted a new PR for the library teams!

If this PR contains changes to any rust-lang/rust public library APIs then please comment with @rustbot label +T-libs-api -T-libs to tag it appropriately. If this PR contains changes to any unstable APIs please edit the PR description to add a link to the relevant API Change Proposal or create one if you haven't already. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary.

Examples of T-libs-api changes:

• Stabilizing library features
• Introducing insta-stable changes such as new implementations of existing stable traits on existing stable types
• Introducing new or changing existing unstable library APIs (excluding permanently unstable features / features without a tracking issue)
• Changing public documentation in ways that create new stability guarantees
• Changing observable runtime behavior of library APIs

[ghost]

@rustbot label +T-libs-api -T-libs

[leonardo-m]

SQRT_3 is useful.
Sometimes in rust code I have also defined:

const LN_3: f64 = 1.0986122886681098;

[ghost]

I've left the addition of ln(3) (and potential others) as an open question on the tracking issue: #103883

This PR just includes the ones in C++ but not Rust, as discussed in the ACP: rust-lang/libs-team#119 (comment)

[pitaj]

@rustbot label -S-waiting-on-review +S-waiting-on-ACP

[Dylan-DPC]

r? @thomcc

[thomcc]

This has ACP+ and these are unstable, so

@bors r+

[bors]

📌 Commit f7dec78 has been approved by thomcc

It is now in the queue for this repository.

[bors]

⌛ Testing commit f7dec78 with merge 1bd0430...

[bors]

☀️ Test successful - checks-actions
Approved by: thomcc
Pushing 1bd0430 to master...

[rust-timer]

Finished benchmarking commit (1bd0430): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.2%	[1.2%, 1.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.6%	[1.6%, 1.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.5%	[-4.5%, -2.6%]	2
All ❌✅ (primary)	1.6%	[1.6%, 1.6%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.9%	[1.3%, 2.4%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 631.432s -> 630.025s (-0.22%)
Artifact size: 316.28 MiB -> 316.26 MiB (-0.00%)