I reinit a fe object with only the same elem kind. Hence, that aspect  
of reallocating memory space due to changing elem types does not seem  
to be a problem.

Why would non-affine maps affect the memory footprint regarding  
caching of information?

Since my mesh geometry does not change during the course of the  
computation, I think storing the N, dN/dx, dN/dy and dN/dz for the  
different quadrature points should work. (I do not need second order  
derivatives). I can either do this external to the fe object (by  
wrapping it in some code that gets this information for each element  
and stores it), or I can simply store the entire fe object for each  
element and initialize it only once.

I am curious about this: doesn't any nonlinear transient computation  
require this information per element per iteration? Am I the first one  
to consider caching this information? How do the CPU/memory overheads  
for your problems work out?

Regards,
Manav




On Oct 18, 2008, at 3:56 PM, John Peterson wrote:

> On Sat, Oct 18, 2008 at 1:04 PM, Manav Bhatia  
> <[EMAIL PROTECTED]> wrote:
>> Hi,
>>
>>   For my application requiring the solution of a nonlinear transient
>> system, I am doing a reinit of the fe object per elem per nonlinear
>> iteration. For larger systems this has started to be a major CPU time
>> expense.
>>
>>   I am now considering saving one fe per elem in memory so that I do
>> not have to do these reinits. Ofcourse, I will be committing a
>> considerable amount of memory as well.
>>
>>   I am writing to ask if anyone has tried this, and could share his/
>> her experiences or comment on this.
>
> I think it depends which part of reinit is taking up the most time.
> If it is the derivative calculations then I'm not sure how much info
> you can really cache.  I'm assuming here you have elements with
> non-affine maps...
>
> If you have a hybrid mesh (a mixture of geometric element types) you
> will probably gain some performance if you loop over all elements of a
> given type instead of switching back and forth repeatedly between
> geometric element types.
>
> -- 
> John


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