Opened 8 years ago
Last modified 6 years ago
#14229 needs_work enhancement
Remove vacuous solutions from solve — at Version 6
Reported by: | ppurka | Owned by: | burcin |
---|---|---|---|
Priority: | major | Milestone: | sage-6.4 |
Component: | symbolics | Keywords: | |
Cc: | kcrisman, jondo | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | port to upstream |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
Sometimes solve and its variants tend to report vacuous solutions. A recent one from ask.sagemath is the following:
sage: x,y = var('x,y') sage: solve([x^2*y^2 <= x^2*y, x^2*y^2 > x^2*y],[x,y]) [[x == 0, 1 < y, 0 != 0], [x == 0, y < 0, 0 != 0]]
Shouldn't we remove these meaningless solutions? The attached patch contains a potential solution. If it seems reasonable, then similar changes could be introduced in solve_ineq
.
The output of the above command after this patch is as expected:
sage: x,y = var('x,y') sage: solve([x^2*y^2 <= x^2*y, x^2*y^2 > x^2*y],[x,y]) []
If you can translate this to maxima proper, please feel free to do so and submit a patch upstream.
Change History (7)
Changed 8 years ago by
comment:1 Changed 8 years ago by
- Description modified (diff)
comment:2 Changed 8 years ago by
- Description modified (diff)
comment:3 Changed 8 years ago by
- Cc kcrisman added
comment:4 Changed 8 years ago by
- Status changed from new to needs_review
comment:5 Changed 8 years ago by
This kind of change should really be made to maxima, not to sage's postprocessing of what maxima returns.
comment:6 Changed 8 years ago by
- Description modified (diff)
- Status changed from needs_review to needs_work
- Work issues set to port to upstream
If someone knows how to translate this to maxima, please feel free to put this upstream. Thanks! [ I can not spend time in learning maxima right now. :( ]
Apply to devel/sage