Fixed floating point issue with asinh function #63698

Phosphorus15 · 2019-08-19T10:38:45Z

This should fixes #63271 , in which asinh(-0.0) returns 0.0 instead of -0.0.
according to @nagisa

IEEE-754 (2008), section 9.2.1:

For the functions expm1, exp2m1, exp10m1, logp1, log2p1, log10p1, sin, tan, sinPi, atanPi, asin, atan, sinh, tanh, asinh, and atanh, f(+0) is +0 and f(−0) is −0 with no exception.

and

sinh(±∞) and asinh(±∞) are ±∞ with no exception.

After ensuring that the function asinh is the only function affected (functions like sin, sinh are all based on cmath library or llvm intrinsics), and that atanh always gives the correct result. The only function to modify is asinh.

Pull from newest repo

rust-highfive · 2019-08-19T10:38:57Z

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @Mark-Simulacrum (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

Mark-Simulacrum · 2019-08-19T18:11:33Z

r? @nagisa perhaps?

Not sure who a good review here would be.

nagisa · 2019-08-19T19:15:03Z

You’ll probably want to use copysign instead and not do computations in abs(x) space only.

tesuji · 2019-08-20T04:44:16Z

src/libstd/f32.rs

-            (self + ((self * self) + 1.0).sqrt()).ln()
+        match self {
+            x if x == NEG_INFINITY => NEG_INFINITY,
+            x => (x + ((x * x) + 1.0).sqrt()).ln().copysign(self)


I would prefer to use if-else directly.

Yea, that sounds reasonable, maybe consider changing the original acosh BTW?

pub fn acosh(self) -> f64 { match self { x if x < 1.0 => NAN, x => (x + ((x * x) - 1.0).sqrt()).ln(), } }

nagisa · 2019-08-27T01:09:54Z

src/libstd/f64.rs

@@ -481,16 +481,16 @@ impl f64 {
    #[stable(feature = "rust1", since = "1.0.0")]
    #[inline]
    #[rustc_deprecated(since = "1.10.0",
-                       reason = "you probably meant `(self - other).abs()`: \
+    reason = "you probably meant `(self - other).abs()`: \


Sorry for changing the identation 😢 , it might because of my IDE's formatter.

nagisa · 2019-08-27T01:11:49Z

@bors r+ rollup

bors · 2019-08-27T01:11:50Z

📌 Commit e33d870 has been approved by nagisa

@nagisa

Fixed floating point issue with asinh function This should fixes rust-lang#63271 , in which `asinh(-0.0)` returns `0.0` instead of `-0.0`. according to @nagisa > > > IEEE-754 (2008), section 9.2.1: > > > For the functions expm1, exp2m1, exp10m1, logp1, log2p1, log10p1, sin, tan, sinPi, atanPi, asin, atan, sinh, tanh, asinh, and atanh, f(+0) is +0 and f(−0) is −0 with no exception. > > and > > > sinh(±∞) and asinh(±∞) are ±∞ with no exception. After ensuring that the function `asinh` is the only function affected (functions like `sin`, `sinh` are all based on `cmath` library or `llvm` intrinsics), and that `atanh` always gives the correct result. The only function to modify is `asinh`.

@nagisa

Fixed floating point issue with asinh function This should fixes rust-lang#63271 , in which `asinh(-0.0)` returns `0.0` instead of `-0.0`. according to @nagisa > > > IEEE-754 (2008), section 9.2.1: > > > For the functions expm1, exp2m1, exp10m1, logp1, log2p1, log10p1, sin, tan, sinPi, atanPi, asin, atan, sinh, tanh, asinh, and atanh, f(+0) is +0 and f(−0) is −0 with no exception. > > and > > > sinh(±∞) and asinh(±∞) are ±∞ with no exception. After ensuring that the function `asinh` is the only function affected (functions like `sin`, `sinh` are all based on `cmath` library or `llvm` intrinsics), and that `atanh` always gives the correct result. The only function to modify is `asinh`.

@ghost

Rollup of 4 pull requests Successful merges: - #62600 (libtest: add --show-output flag to print stdout of successful tests) - #63698 (Fixed floating point issue with asinh function) - #63761 (Propagate spans and attributes from proc macro definitions) - #63917 (Error when generator trait is not found) Failed merges: r? @ghost

Pkgsrc changes: * Remove patch which no longer applies (but what about RPATH?) * Adapt a few patches to changed files upstream. Upstream changes: Version 1.39.0 (2019-11-07) =========================== Language -------- - [You can now create `async` functions and blocks with `async fn`, `async move {}`, and `async {}` respectively, and you can now call `.await` on async expressions.][63209] - [You can now use certain attributes on function, closure, and function pointer parameters.][64010] These attributes include `cfg`, `cfg_attr`, `allow`, `warn`, `deny`, `forbid` as well as inert helper attributes used by procedural macro attributes applied to items. e.g. ```rust fn len( #[cfg(windows)] slice: &[u16], #[cfg(not(windows))] slice: &[u8], ) -> usize { slice.len() } ``` - [You can now take shared references to bind-by-move patterns in the `if` guards of `match` arms.][63118] e.g. ```rust fn main() { let array: Box<[u8; 4]> = Box::new([1, 2, 3, 4]); match array { nums // ---- `nums` is bound by move. if nums.iter().sum::<u8>() == 10 // ^------ `.iter()` implicitly takes a reference to `nums`. => { drop(nums); // ----------- Legal as `nums` was bound by move and so we have ownership. } _ => unreachable!(), } } ``` Compiler -------- - [Added tier 3\* support for the `i686-unknown-uefi` target.][64334] - [Added tier 3 support for the `sparc64-unknown-openbsd` target.][63595] - [rustc will now trim code snippets in diagnostics to fit in your terminal.] [63402] **Note** Cargo currently doesn't use this feature. Refer to [cargo#7315][cargo/7315] to track this feature's progress. - [You can now pass `--show-output` argument to test binaries to print the output of successful tests.][62600] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [`Vec::new` and `String::new` are now `const` functions.][64028] - [`LinkedList::new` is now a `const` function.][63684] - [`str::len`, `[T]::len` and `str::as_bytes` are now `const` functions.][63770] - [The `abs`, `wrapping_abs`, and `overflowing_abs` numeric functions are now `const`.][63786] Stabilized APIs --------------- - [`Pin::into_inner`] - [`Instant::checked_duration_since`] - [`Instant::saturating_duration_since`] Cargo ----- - [You can now publish git dependencies if supplied with a `version`.] [cargo/7237] - [The `--all` flag has been renamed to `--workspace`.][cargo/7241] Using `--all` is now deprecated. Misc ---- - [You can now pass `-Clinker` to rustdoc to control the linker used for compiling doctests.][63834] Compatibility Notes ------------------- - [Code that was previously accepted by the old borrow checker, but rejected by the NLL borrow checker is now a hard error in Rust 2018.][63565] This was previously a warning, and will also become a hard error in the Rust 2015 edition in the 1.40.0 release. - [`rustdoc` now requires `rustc` to be installed and in the same directory to run tests.][63827] This should improve performance when running a large amount of doctests. - [The `try!` macro will now issue a deprecation warning.][62672] It is recommended to use the `?` operator instead. - [`asinh(-0.0)` now correctly returns `-0.0`.][63698] Previously this returned `0.0`. [62600]: rust-lang/rust#62600 [62672]: rust-lang/rust#62672 [63118]: rust-lang/rust#63118 [63209]: rust-lang/rust#63209 [63402]: rust-lang/rust#63402 [63565]: rust-lang/rust#63565 [63595]: rust-lang/rust#63595 [63684]: rust-lang/rust#63684 [63698]: rust-lang/rust#63698 [63770]: rust-lang/rust#63770 [63786]: rust-lang/rust#63786 [63827]: rust-lang/rust#63827 [63834]: rust-lang/rust#63834 [63927]: rust-lang/rust#63927 [63933]: rust-lang/rust#63933 [63934]: rust-lang/rust#63934 [63938]: rust-lang/rust#63938 [63940]: rust-lang/rust#63940 [63941]: rust-lang/rust#63941 [63945]: rust-lang/rust#63945 [64010]: rust-lang/rust#64010 [64028]: rust-lang/rust#64028 [64334]: rust-lang/rust#64334 [cargo/7237]: rust-lang/cargo#7237 [cargo/7241]: rust-lang/cargo#7241 [cargo/7315]: rust-lang/cargo#7315 [`Pin::into_inner`]: https://doc.rust-lang.org/std/pin/struct.Pin.html#method.into_inner [`Instant::checked_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_duration_since [`Instant::saturating_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.saturating_duration_since

Phosphorus15 added 3 commits August 19, 2019 00:34

Merge pull request #1 from rust-lang/master

92f08b7

Pull from newest repo

Added negative cases for asinh according to IEEE-754.

c456934

test cases for both f32 and f64 on asinh(-0.0)

64e3a10

rust-highfive assigned Mark-Simulacrum Aug 19, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Aug 19, 2019

rust-highfive assigned nagisa and unassigned Mark-Simulacrum Aug 19, 2019

Mark-Simulacrum added relnotes Marks issues that should be documented in the release notes of the next release. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. labels Aug 19, 2019

Centril added this to the 1.39 milestone Aug 19, 2019

Used copysign to avoid unnecessary branches.

535efa4

tesuji reviewed Aug 20, 2019

View reviewed changes

Refined implementations of asinh and acosh

e33d870

nagisa reviewed Aug 27, 2019

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nagisa approved these changes Aug 27, 2019

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 27, 2019

Centril mentioned this pull request Aug 27, 2019

Rollup of 5 pull requests #63936

Closed

Centril mentioned this pull request Aug 27, 2019

Rollup of 4 pull requests #63940

Merged

bors merged commit e33d870 into rust-lang:master Aug 27, 2019

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Fixed floating point issue with asinh function #63698

Fixed floating point issue with asinh function #63698

Phosphorus15 commented Aug 19, 2019 •

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nagisa Aug 27, 2019

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nagisa commented Aug 27, 2019

bors commented Aug 27, 2019

Fixed floating point issue with asinh function #63698

Fixed floating point issue with asinh function #63698

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