#6948 closed defect (fixed)
[with patch, positive review] powers of exp are over simplified
Reported by: | burcin | Owned by: | burcin |
---|---|---|---|
Priority: | critical | Milestone: | sage-4.1.2 |
Component: | symbolics | Keywords: | |
Cc: | Merged in: | Sage 4.1.2.alpha4 | |
Authors: | Burcin Erocal | Reviewers: | Karl-Dieter Crisman |
Report Upstream: | Work issues: | ||
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Francois Maltey wrote on sage-support:
var("a,b,c") exp(a)^2 # returns exp(2a) is right exp(a)^(1/2) # returns exp (a/2) is wrong, with a=2*i*pi we get -1=1 exp(a)^b # returns exp(a*b) is wrong
The thread is here:
http://groups.google.com/group/sage-support/browse_thread/thread/330a015bf640a4f3/0ddfdd5a4e021579
Attachments (2)
Change History (9)
Changed 13 years ago by
comment:1 Changed 13 years ago by
- Status changed from new to assigned
- Summary changed from powers of exp are over simplified to [with patch, waiting for new pynac] powers of exp are over simplified
comment:2 Changed 13 years ago by
- Summary changed from [with patch, waiting for new pynac] powers of exp are over simplified to [with patch, needs review] powers of exp are over simplified
New pynac package available at #6993.
comment:3 Changed 13 years ago by
- Summary changed from [with patch, needs review] powers of exp are over simplified to [with patch, needs work] powers of exp are over simplified
Nice, but does it actually fix the examples provided?
sage: exp(a)^(1/2) sqrt(e^a)
I guess that's okay. But
sage: exp(a)^(1/3) e^a^(1/3) sage: exp(a^(1/3)) e^(a^(1/3))
I think there are missing parentheses in the first example, particularly because it's not typeset. Even if that is a convention, which I'm not so sure of, the dictum is that it's better to be explicit.
I also get a doctest failure (not mentioned in the Pynac upgrade ticket) in product and quotient rule differentiation in calculus/tests.py, but it looks like that's the one in #6524, so it's properly speaking another issue, I guess.
comment:4 Changed 13 years ago by
- Summary changed from [with patch, needs work] powers of exp are over simplified to [with patch, needs review] powers of exp are over simplified
This package should fix this problem:
http://sage.math.washington.edu/home/burcin/pynac/pynac-0.1.9.p0.spkg
I'll attach a patch with some more doctests now.
Changed 13 years ago by
comment:5 Changed 13 years ago by
- Reviewers set to Karl-Dieter Crisman
- Summary changed from [with patch, needs review] powers of exp are over simplified to [with patch, positive review] powers of exp are over simplified
Positive review!
comment:6 Changed 13 years ago by
- Merged in set to Sage 4.1.2.alpha3
- Resolution set to fixed
- Status changed from assigned to closed
Merged both patches.
comment:7 Changed 13 years ago by
- Merged in changed from Sage 4.1.2.alpha3 to Sage 4.1.2.alpha4
There is no 4.1.2.alpha3. Sage 4.1.2.alpha3 was William Stein's release for working on making the notebook a standalone package.
This is fixed in my pynac tree, attachment:trac_6948-exp_power.patch is the corresponding patch for Sage. I will release a pynac spkg with some more fixes and post instructions for review.