Opened 4 years ago
Last modified 6 weeks ago
#8728 new defect
Incorrect integral from Maxima
Reported by: | kcrisman | Owned by: | burcin |
---|---|---|---|
Priority: | major | Milestone: | sage-6.4 |
Component: | calculus | Keywords: | |
Cc: | Merged in: | ||
Authors: | Reviewers: | ||
Report Upstream: | Fixed upstream, but not in a stable release. | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
From #sage-devel:
Boulemans left the chat room. (Read error: Connection reset by peer) [11:58am] Boule joined the chat room. [11:58am] Boule: (laptop shutdown due to power supply) [11:59am] Boule: e, T, w = var("e T w"); assume(1 = e^2)>0; integrate(cos(w+T)/(1+e*cos(T))^2,T,0,2*pi) should give -2*pi e cos w/(1-e^2)^3/2 instead of 0 [11:59am] Boule: can someone help? [12:00pm] wjp: yeah, sage seems to have some trouble with this integral. You could try http://groups.google.com/group/sage-support since the right people don't seem to be here currently [12:00pm] Boule: ok, thanx [12:08pm] kcrisman: By the way, I just tried this and get a hang in Maxima. Can you type the exact commands which lead to an answer of 0? [12:08pm] kcrisman: If I plug something (.5, .75) in for e in Maxima in Sage, I do get zero as an output. [12:12pm] Boule: don't know maxima, but with numerical values for e and w at wolfram-alfa, it gives something different than 0 [12:13pm] wjp: *nod* maple gives non-zeros too [12:13pm] kcrisman: Can you give the *exact* sequence of commands which yield zero in Sage itself? [12:14pm] Boule: e = var('e') [12:14pm] Boule: T = var('T') [12:14pm] Boule: w = var('w') [12:14pm] baali1 joined the chat room. [12:14pm] baali left the chat room. (Quit: Leaving.) [12:15pm] Boule: assume(1-e^2>0) [12:15pm] Boule: integrate(cos(w+T)/(1+e*cos(T))^2,T,0,2*pi) [12:15pm] kcrisman: Okay, that's what I thought. [12:16pm] kcrisman: Okay, it takes a while but I do get 0.
Change History (16)
comment:1 follow-up: ↓ 6 Changed 4 years ago by jason
comment:2 Changed 4 years ago by jason
#8729 may point to a solution.
comment:3 Changed 4 years ago by kcrisman
Hmm, I forgot about this, and it's true it never got implemented, did it?
comment:4 Changed 4 years ago by jason
It was fixed about two weeks ago in maxima. There was a new release of maxima a few days ago---I'm trying to make an spkg right now.
comment:5 Changed 4 years ago by kcrisman
Sweet. I haven't been keeping up on the Maxima list lately, thanks.
comment:6 in reply to: ↑ 1 Changed 4 years ago by jason
Replying to jason:
I wonder if this is another manifestation of this bug:
sage: integrate(sqrt(sin(x)^2+cos(x)^2), x,0,2*pi) pi
I just checked; this ticket isn't the same bug.
comment:7 Changed 4 years ago by jason
The upgrade to maxima 5.21.1 does not fix this. After #8731:
sage: e, T, w = var("e T w") sage: assume(1-e^2>0) sage: integrate(cos(w+T)/(1+e*cos(T))^2,T,0,2*pi) 0
comment:8 Changed 4 years ago by kcrisman
Maxima 5.23.2 still has this, and we still haven't reported it.
Maxima 5.23.2 http://maxima.sourceforge.net using Lisp SBCL 1.0.24 Distributed under the GNU Public License. See the file COPYING. Dedicated to the memory of William Schelter. The function bug_report() provides bug reporting information. (%i1) assume(1-e^2>0); 2 (%o1) [e < 1] (%i3) integrate(cos(w+T)/(1+e*cos(T))^2,T,0,2*%pi); (%o3) 0
This is now Maxima bug 3211975.
comment:9 Changed 3 years ago by kcrisman
- Report Upstream changed from Not yet reported upstream; Will do shortly. to Fixed upstream, but not in a stable release.
According to the bug report, this is now fixed. However, some examples may still throw a Lisp error, so we should check out whether that will affect us before saying we're totally fixed when we upgrade.
comment:10 Changed 2 years ago by kcrisman
Maxima 5.28 is now out.
comment:11 Changed 20 months ago by kcrisman
See #13973 where this should (?) be fixed, just need a doctest here?
comment:12 Changed 13 months ago by jdemeyer
- Milestone changed from sage-5.11 to sage-5.12
comment:13 Changed 8 months ago by vbraun_spam
- Milestone changed from sage-6.1 to sage-6.2
comment:14 Changed 5 months ago by vbraun_spam
- Milestone changed from sage-6.2 to sage-6.3
comment:15 Changed 4 months ago by pbruin
In Maxima 5.33.0 (see #13973):
(%i1) assume(e^2<1); 2 (%o1) [e < 1] (%i2) integrate(cos(w+T)/(1+e*cos(T))^2, T, 0, 2*%pi); 2 Is abs(e) - sqrt(1 - e ) - 1 positive, negative or zero? negative; ! 2 ! Is !sqrt(1 - e ) - 1! - abs(e) positive, negative or zero? negative; 2 2 %pi e sqrt(1 - e ) cos(w) (%o2) - --------------------------- 4 2 e - 2 e + 1
This appears to be the correct answer. Note that the answers to both questions are "negative" for all e with -1 < e < 1, so it would be nice if Maxima didn't ask those questions.
comment:16 Changed 6 weeks ago by vbraun_spam
- Milestone changed from sage-6.3 to sage-6.4
I wonder if this is another manifestation of this bug: