Adds an expm1 function for complex values. #6539
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
|
||
| function expm1(z::Complex) | ||
| zr,zi = reim(z) | ||
| if isfinite(zr) && !isfinite(zi) return Complex(oftype(zr, NaN), oftype(zi, NaN)) end |
There was a problem hiding this comment.
To reduce the number of comparisons in the common case of finite values, it would be better to check for infinities only once in this case. i.e.
if isfinite(zr)
if isfinite(zi)
....
else
....
end
else # infinite or NaN zr
....
end
There was a problem hiding this comment.
That's true, and it would make it much easier to understand.
|
I've refactored both |
|
I'm not sure why travis broke, but it appears to be unrelated to the PR. |
…that cos(x) - 1 = -2*sin(x/2)^2 There is some cancellation error when real(z) ~ imag(z)^2/2 for small z, but otherwise is fairly stable.
|
I've squashed the commits: is there anything holding this back? |
| wi = er*(isfinite(zi) ? sin(zi) : zi) | ||
| Complex(wr, wi) | ||
| if isnan(zr) | ||
| Complex(zr, zi==zero(zi) ? zi : zr) |
There was a problem hiding this comment.
Not important but just FYI, zero() is not necessary in this context (since it's an argument and not a return value).
JeffBezanson
added a commit
that referenced
this pull request
May 20, 2014
Adds an expm1 function for complex values.
This was referenced May 21, 2014
Merged
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Partially addresses #3141. It uses the property that
There is some cancellation error when
real(z)~imag(z)^2/2for smallz, but otherwise is fairly stable.I also removed some unnecessary branching conditions from the complex
exp.