#719 closed bug (fixed)
reduce (integers, mixed ordering) does not terminate
Reported by: | ren | Owned by: | ren |
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Priority: | major | Milestone: | 4-1-0 and higher |
Component: | dontKnow | Version: | 4-0-2 |
Keywords: | Cc: |
Description (last modified by )
Here is a suspicious example of reduce not terminating:
ring r = integer,(t,x(1..5)),ws(1,-1,-1,-1,-1,-1); poly h = 3*t*x(2)*x(4)-21*t*x(1)*x(5)-12*t^2*x(1)*x(2)-2*t^2*x(1)*x(3)-6*t^2*x(1)*x(4); ideal G = x(2)+6*x(4)+7*x(5)+4*t*x(2), x(2)+8*x(3)+7*x(5)+t*x(2), t*x(1)+3*t*x(2)+t^2*x(1), t*x(4)+21*t*x(5)+12*t^2*x(2)+2*t^2*x(3)+7*t^2*x(4), 2-t; G = std(G); reduce(h,G);
What makes it suspicious is, if you are using a debug version and enable option "teach" (see attachment), you notice that it keeps reducing the same degree 2 monomials in x but with increasing degree in t, which keeps increasing because of 2-t.
This is not what I would expect. I'd expect some leading ideal to stabilize and the algorithm to terminate.
Attachments (1)
Change History (9)
Changed 8 years ago by
Attachment: | reduceBugShort.out added |
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comment:1 Changed 8 years ago by
Description: | modified (diff) |
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comment:2 Changed 8 years ago by
Description: | modified (diff) |
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comment:3 Changed 8 years ago by
Resolution: | → fixed |
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Status: | new → closed |
comment:5 Changed 8 years ago by
Resolution: | fixed |
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Status: | closed → reopened |
still does not terminate, mistakenly checked an easier computation (which did not terminate in Singular but in Adi's version).
comment:6 Changed 8 years ago by
Description: | modified (diff) |
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comment:7 Changed 8 years ago by
Owner: | changed from somebody to ren |
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Status: | reopened → new |
comment:8 Changed 7 years ago by
Resolution: | → fixed |
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Status: | new → closed |
fixed with 67e0dc31cecb425433f640594911fc9df2b15076 tests: New/stdZtests.tst
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output with "option(teach);"