On Thu, Jan 5, 2012 at 4:07 AM, Dominik Szczerba <span dir="ltr"><<a href="mailto:dominik@itis.ethz.ch">dominik@itis.ethz.ch</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Is it also possible that MaxAbs would be computed wrongly? I get a<br>
different value when I compute it myself.</blockquote><div><br></div><div>Yes, that is possible. Here is the code:</div><div><br></div><div> <a href="http://petsc.cs.iit.edu/petsc/petsc-dev/annotate/d1799f05bf01/src/mat/impls/aij/seq/aij.c#l2628">http://petsc.cs.iit.edu/petsc/petsc-dev/annotate/d1799f05bf01/src/mat/impls/aij/seq/aij.c#l2628</a></div>
<div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="HOEnZb"><font color="#888888"><br>
Dominik<br>
</font></span><div class="HOEnZb"><div class="h5"><br>
On Thu, Jan 5, 2012 at 1:02 AM, Barry Smith <<a href="mailto:bsmith@mcs.anl.gov">bsmith@mcs.anl.gov</a>> wrote:<br>
><br>
> On Jan 4, 2012, at 5:42 PM, Matthew Knepley wrote:<br>
><br>
>> On Wed, Jan 4, 2012 at 5:29 PM, Dominik Szczerba <<a href="mailto:dominik@itis.ethz.ch">dominik@itis.ethz.ch</a>> wrote:<br>
>> Do you think this issue can potentially explain a behavior I observe:<br>
>><br>
>> In my big block shell matrix there are two blocks submatrices: (say) B<br>
>> and B transposed. MaxAbs is exact same for both submatrices, MinAbs is<br>
>> zero for B (as expected), but small negative for the other<br>
>> (unexpected).<br>
>><br>
>> Now question: do I have a bug (that I do not immediately see) or this<br>
>> can be hopefully only a trick in MinAbs?<br>
>><br>
>> It was a bug in MinAbs. I am pushing the fix.<br>
><br>
> To 3.2 I hope. Please send the patch link for 3.2 as Satish did just a little while ago for another bug.<br>
><br>
> Barry<br>
><br>
>><br>
>> Matt<br>
>><br>
>> Thanks a lot.<br>
>><br>
>> On Wed, Jan 4, 2012 at 6:05 PM, Jed Brown <<a href="mailto:jedbrown@mcs.anl.gov">jedbrown@mcs.anl.gov</a>> wrote:<br>
>> > On Wed, Jan 4, 2012 at 11:02, Matthew Knepley <<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>> wrote:<br>
>> >><br>
>> >> Okay, here is what is wrong with the logic:<br>
>> >><br>
>> >> 1) Its not a shift, it ignores values < 1.0e-12<br>
>> ><br>
>> ><br>
>> > you wrote that in the commit message<br>
>> ><br>
>> >><br>
>> >><br>
>> >> 2) The problem is on line 2.17 of the diff where it takes the first value<br>
>> >> as minimum, but does not take the absolute value<br>
>> ><br>
>> ><br>
>> > good catch<br>
>><br>
>><br>
>><br>
>> --<br>
>> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>
>> -- Norbert Wiener<br>
><br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>
-- Norbert Wiener<br>