Changes between Initial Version and Version 1 of Ticket #25076, comment 35


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Timestamp:
04/02/18 14:47:55 (3 years ago)
Author:
SimonKing
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  • Ticket #25076, comment 35

    initial v1  
    1111So, given the poor performance I demonstrated, there is an issue here that goes beyond what was fixed in #24742, and it is related with what the ticket description of this ticket says.
    1212
    13 In addition, I notice that the current implementation of _mul_long for Matrix_gfpn_dense doesn't convert an integer into GF(p^n,'x') by reduction modulo p, but by some conversion used by !MeatAxe. For instance, 4 would be converted to the number x+1 in GF(9,'x'). I didn't notice it before since in my cohomology applications I work with matrices over prime fields, where the different conversions happen to coincide.
     13In addition, I notice that the current implementation of _mul_long for Matrix_gfpn_dense doesn't convert an integer into `GF(p^n,'x')` by reduction modulo p, but by some conversion used by !MeatAxe. For instance, 4 would be converted to the number x+1 in GF(9,'x'). I didn't notice it before since in my cohomology applications I work with matrices over prime fields, where the different conversions happen to coincide.
    1414
    1515Hence, if this ticket is about to "Fix Matrix_gfpn_dense*int", then here one should