Opened 11 years ago
Last modified 6 years ago
#9548 new defect
Sage does not support infinities with complex direction
Reported by: | fredrik.johansson | Owned by: | AlexGhitza |
---|---|---|---|
Priority: | major | Milestone: | sage-wishlist |
Component: | algebra | Keywords: | |
Cc: | Merged in: | ||
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
This should do something reasonable:
sage: Infinity * I --------------------------------------------------------------------------- ArithmeticError Traceback (most recent call last) /home/fredrik/sage/<ipython console> in <module>() /home/fredrik/sage/local/lib/python2.6/site-packages/sage/structure/element.so in sage.structure.element.RingElement.__mul__ (sage/structure/element.c:11428)() /home/fredrik/sage/local/lib/python2.6/site-packages/sage/structure/coerce.so in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:6123)() /home/fredrik/sage/local/lib/python2.6/site-packages/sage/structure/element.so in sage.structure.element.RingElement.__mul__ (sage/structure/element.c:11356)() /home/fredrik/sage/local/lib/python2.6/site-packages/sage/symbolic/expression.so in sage.symbolic.expression.Expression._mul_ (sage/symbolic/expression.cpp:11042)() ArithmeticError: x*Infinity with non real x encountered.
Change History (3)
comment:1 Changed 7 years ago by
- Milestone set to sage-wishlist
comment:2 Changed 6 years ago by
This may be a stupid question but now that we have complex (unsigned) infinity, shouldn't that be the result of I*Infinity
?
comment:3 Changed 6 years ago by
I don't know. It would definitely be useful to be able to write things like integrals from 0 to i∞, (1+i)∞, or exp(iθ)∞. Whether I*infinity
should return on of these “directional” infinities or unsigned infinity is another question. Without thinking, I'd say I*PlusInfinity()
should return the former and I*UnsignedInfinity()
the latter.
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I*Infinity
now returns an element of the symbolic ring. I'm leaving the ticket open (as a wishlist item), though, since it would probably make sense to make infinities with complex direction more similar to ±∞.