Changes between Initial Version and Version 1 of Ticket #6196


Ignore:
Timestamp:
2020-11-08T23:52:20Z (4 years ago)
Author:
Francesco Casella
Comment:

Legend:

Unmodified
Added
Removed
Modified

  • Ticket #6196 – Description

    initial v1  
    1717It is immediate to see that the term {{{transformer.conv2.terminal_p.i[1]}}} appears both in {{{transformer.conv3.terminal_p.i[1]}}} and in {{{transformer.conv1.terminal_p.i[1]}}}, so when those two are subtracted to compute the residual, its sensitivity w.r.t. its unknown is zero.
    1818
    19 I don't know what criterion is used to perform linear tearing, but it's obviously not a good one. Linear systems should be solved with proper pivoting, solving some equations according only to structural information but disregarding the coefficient values can be very dangerous.
     19I don't know what criterion is used to perform linear tearing, but it's obviously not a good one. Linear systems should be solved with proper pivoting; solving some equations according only to structural information but disregarding the coefficient values can be very dangerous.
    2020
    2121Until this issue is solved, I would recommend to disable linear tearing by default. This will sure enough solve a lot of problems in the testsuite. BTW, now that we have sparse solvers to deal with large linear systems, the usefulness of linear tearing is probably quite limited.