[petsc-dev] [Fortran] MatLoad() error: MatLoad is not supported for type: mpiaij!

[Barry Smith]

  Jed,

    Thanks for your help on this.

    So is the current problem (with the MatLoad) essentially solved? and we can close this case.

   Barry

On Sep 3, 2010, at 1:01 PM, Jed Brown wrote:

> On Fri, 3 Sep 2010 12:53:07 -0500, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> 
>> On Sep 3, 2010, at 12:52 PM, Jed Brown wrote:
>> 
>>> On Fri, 3 Sep 2010 11:57:59 -0500, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>>> 
>>>> Jed,
>>>> 
>>>>   Any sorting algorithm that gives good performance is what we need. The particular algorithm class doesn't matter.
>>> 
>>> The issue is the possibility/probability of hitting a bad-case for
>>> quicksort.  Robust quicksorts usually do something different if they
>>> detect that pivot choice is going poorly (like do a lot of work to
>>> choose a good pivot or switch to heapsort).  Heapsort usually costs
>>> slightly more than quicksort, but I think most users would be willing to
>>> pay that in exchange for guaranteed O(n log n) performance (as far as I
>>> know, sorting is never an especially performance-sensitive kernel in
>>> PETSc, but it's a big deal if 1 second turns into hours occasionally
>>> (e.g. when the mesh is changed)).
>> 
>>   Ok, when we add drop tolerance ILU this requires something like a sort and we found the sort was really making the factorization slow.
> 
> Okay, I'll keep that in mind and hopefully get around to putting in a
> robust sort with good constants.
> 
> Jed