Changes between Initial Version and Version 6 of Ticket #13609


Ignore:
Timestamp:
11/21/12 15:54:50 (9 years ago)
Author:
burcin
Comment:

I uploaded a new patch with some text trac_13609-gf2_content.take2.patch. To demonstrate the content of the expressions involved, I wrapped GiNaC's content() method in #13736. This ticket now depends on the patch there.

Note that multiplying the numerator I give in the doctests by the content gives

sage: -num.content(c1)*num
c1 + z*c2 + z

which changes the original leading coefficient -1 by coercing it to GF(2^8).

This does not happen during normalization, since numeric::div_dyn() is used directly to modify the coefficients. There is a shortcut in that function to do nothing if we are dividing by 1. Perhaps I should back out the current fix in Pynac and change numeric::div_dyn() to disable the shortcut if the characteristic is not 0.

Comments?

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  • Ticket #13609

    • Property Status changed from new to needs_review
    • Property Authors changed from to Burcin Erocal
    • Property Component changed from PLEASE CHANGE to symbolics
    • Property Keywords pynac segfault added
    • Property Dependencies changed from to #13729, #13736
    • Property Owner changed from tbd to burcin
    • Property Reviewers changed from to Jean-Pierre Flori
  • Ticket #13609 – Description

    initial v6  
    5858
    5959Any idea of what is going wrong here?
     60
     61Apply [attachment:trac_13609-gf2_content.take2.patch]