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| A bug in a ring with matrix ordering https://www.singular.uni-kl.de/forum/viewtopic.php?f=10&t=2899 |
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| Author: | kwankyu [ Wed Jan 08, 2020 4:11 am ] |
| Post subject: | A bug in a ring with matrix ordering |
Let us create a ring with a matrix ordering: {{{ > intmat m[3][3] = 3, 0, 1, 0, 1, 0, 0, 0, 1; > ring R = 0, (x,y,z), M(m); > x > 1; 1 > y > 1; 1 > z > 1; 1 }}} Hence the monomial ordering of R is a well-ordering, and the value of internal attribute `OrdSgn` of R should be 1. But presently `OrdSgn` of R is set to -1. There seems to be a bug in the implementation of `rCheckOrdSgn` function in `libpolys/polys/monomials/ring.cc` file. This bug was revealed while fixing a bug of Sage tracked in #28954. |
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| Author: | hannes [ Fri Jan 10, 2020 3:55 pm ] |
| Post subject: | Re: A bug in a ring with matrix ordering |
fixed with git commit 3484489a559567285e5422a2a18fd88fb5a60600 Author: Hans Schoenemann <hannes@mathematik.uni-kl.de> Date: Fri Jan 10 14:53:21 2020 +0100 fix: OrdSgn for matrix orderings with 0 in first row |
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| Author: | kwankyu [ Mon Jan 13, 2020 5:41 am ] |
| Post subject: | Re: A bug in a ring with matrix ordering |
I checked that the patch works well in Sage. Thank you! |
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