Opened 3 years ago
Closed 3 years ago
#24883 closed defect (fixed)
Endless symbolic computation
Reported by:  ipasquinelli  Owned by:  

Priority:  major  Milestone:  sage8.4 
Component:  symbolics  Keywords:  days93, days94 
Cc:  rws, vdelecroix  Merged in:  
Authors:  Irene Pasquinelli  Reviewers:  Ralf Stephan, Travis Scrimshaw 
Report Upstream:  N/A  Work issues:  
Branch:  4d0c51e (Commits, GitHub, GitLab)  Commit:  4d0c51eab2f477499b6f7c64b5e7d179f8063cf2 
Dependencies:  #24838  Stopgaps: 
Description (last modified by )
I tried calculating
a=e^(I*pi/4)+1 b=1e^(I*pi/4) a*b
and both expressions a*b and a/b don't stop computing.
I tried both on sage8.1 for Windows and on sage8.2.beta6 on Ubuntu (native Ubuntu desktop on Windows10).
Change History (23)
comment:1 Changed 3 years ago by
comment:2 Changed 3 years ago by
Alternative computation that terminates:
UCF = UniversalCyclotomicField() a = UCF.zeta(8) + 1 b = 1  UCF.zeta(8) a * b
comment:3 Changed 3 years ago by
 Description modified (diff)
comment:4 Changed 3 years ago by
I can confirm it on archlinux with compiled sage8.2.beta6, sage8.2.beta5 and sage8.1. However, with the sagemath 8.111 from the archlinux community repository it does work.
sage: a = 1 + e^(I*pi/4) sage: b = 1  e^(I*pi/4) sage: a*b 1/4*((I + 1)*sqrt(2)  2)*((I + 1)*sqrt(2)  2) sage: a/b 1/2*((I + 1)*sqrt(2)  2)/((1/2*I + 1/2)*sqrt(2) + 1)
comment:5 Changed 3 years ago by
Confirmed in beta6. The loop is in Pynac. Thanks for the report.
comment:6 followup: ↓ 7 Changed 3 years ago by
Actually there were changes in pynac0.7.17 that appear to have fixed it. With #24838:
sage: sage: a = 1 + e^(I*pi/4) ....: sage: b = 1  e^(I*pi/4) ....: sage: a*b ....: 1/4*((I + 1)*sqrt(2)  2)*((I + 1)*sqrt(2)  2)
We might doctest this in this ticket, though.
comment:7 in reply to: ↑ 6 Changed 3 years ago by
comment:8 Changed 3 years ago by
Ralf, Irene is working on this ticket (she is learning how to develop). We will have a branch in a minute. Thanks for pointing #24838.
comment:9 Changed 3 years ago by
 Branch set to u/ipasquinelli/24883
 Commit set to efe5f145b805b60d72a12eaf9c57a5109e0c786a
 Status changed from new to needs_review
comment:10 Changed 3 years ago by
 Dependencies set to #24838
comment:11 Changed 3 years ago by
 Reviewers set to Ralf Stephan
I think this is fine, but we may have to wait for setting positive until #24838 gets positive.
comment:12 Changed 3 years ago by
 Branch changed from u/ipasquinelli/24883 to public/24883
comment:13 Changed 3 years ago by
 Commit changed from efe5f145b805b60d72a12eaf9c57a5109e0c786a to 699c0a2215c0b2472a70170b89947d28021deb05
comment:14 Changed 3 years ago by
 Keywords days94 added
 Milestone changed from sage8.2 to sage8.3
 Reviewers changed from Ralf Stephan to Ralf Stephan, Travis Scrimshaw
 Status changed from needs_review to positive_review
LGTM.
comment:16 Changed 3 years ago by
Problem actually comes from an earlier doctest:
sage: e = x+1 <= x2
(I tested this by copy/pasting the doctest).
So we probably need to use exp
.
comment:17 Changed 3 years ago by
 Commit changed from 699c0a2215c0b2472a70170b89947d28021deb05 to cb24f9a42dbddb869f40479b513e21c52d1200ae
Branch pushed to git repo; I updated commit sha1. New commits:
cb24f9a  24883: improve usage of ambigous symbol in doctest

comment:18 Changed 3 years ago by
 Status changed from needs_work to needs_review
comment:19 Changed 3 years ago by
 Milestone changed from sage8.3 to sage8.4
update milestone 8.3 > 8.4
comment:20 Changed 3 years ago by
 Status changed from needs_review to positive_review
Forgot about this. LGTM.
comment:21 followup: ↓ 22 Changed 3 years ago by
 Commit changed from cb24f9a42dbddb869f40479b513e21c52d1200ae to 4d0c51eab2f477499b6f7c64b5e7d179f8063cf2
 Status changed from positive_review to needs_review
Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:
4d0c51e  Merge with sage8.3

comment:22 in reply to: ↑ 21 Changed 3 years ago by
 Status changed from needs_review to positive_review
comment:23 Changed 3 years ago by
 Branch changed from public/24883 to 4d0c51eab2f477499b6f7c64b5e7d179f8063cf2
 Resolution set to fixed
 Status changed from positive_review to closed
Could you add your architecture/sage version in the ticket description? I can confirm the behavior on archlinux with compiled sage8.2.beta6.