[petsc-users] How to read/write unstructured mesh in parallel

[Jed Brown]

On Tue, Nov 20, 2012 at 1:08 AM, Fande Kong <fd.kong at siat.ac.cn> wrote:

> It seems to be a good idea. I have another related question. If all
> processors read the same file at the same time, would it be very slow for
> conflicting access?


Yes, though it's much better if you use MPI-IO collective IO. The worst is
if every process reads a different file.


>
>
> On Mon, Nov 19, 2012 at 4:52 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
>
>> On Tue, Nov 20, 2012 at 12:38 AM, Fande Kong <fd.kong at siat.ac.cn> wrote:
>>
>>> I want to try very 'large' mesh.  I guess it should be bottleneck.
>>
>>
>> It's really worth profiling. Having every process read directly is no
>> more scalable (frequently less, actually) than having rank 1 read
>> incrementally and send to whoever should own it. You can do full parallel
>> IO, but the code depends on the mesh format.
>>
>
>
>
> --
> Fande Kong
> ShenZhen Institutes of Advanced Technology
> Chinese Academy of Sciences
>
>
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