[overture] Re: data overflow
- From: Petr Hotmar <petr.hotmar@xxxxxxxxx>
- To: overture@xxxxxxxxxxxxx
- Date: Thu, 3 Jun 2010 16:53:06 -0400
I would like to understand better if and how I can control filling of
coefficient matrices and prevent generation of any additional unwanted
arrays. Any ideas on how to modify the 'high-level' interface so as to
increase memory efficiency?
Having 140,000 grid points, 3D and 4 variables, I would expect the
coefficient matrix (of floats) to be ~ 240MB. However,
coeff.setIsACoefficientMatrix consumes 0.4GB and the subsequent filling
(coeff=xCoefficients(...) etc.), specifically the scalar assignment
#0 doubleMappedGridFunction::operator= (this=0xad7fa68, x=0) at
doubleMappedGridFunction.C:2779
#1 0x011cbceb in GenericCompositeGridOperators::yCoefficients
(this=0xbff94e80, C1=@0xbff98460, C2=@0xbff9844c, C3=@0x839e770,
C4=@0x839e770) at GenericCompositeGridOperators.C:564,
consumes my remaining 2GB (?!) of RAM, crashing with HEAP ERROR. Can I
prevent this? Also, are the doubles being used instead of floats (the error
mentions MDI_double_Allocate)?
Thank you,
Petr
On Sun, Mar 8, 2009 at 11:00 PM, Petr Hotmar <petr.hotmar@xxxxxxxxx> wrote:
> Data overflow
> I'm solving a system of two simple Helmholtz equations on a single
> rectangular 3D grid using coefficient matrices. After relatively mild
> refinement of the grid (from 20x20x20 to 50x50x50 grid lines), the
> code crashes upon filling coeffs for interior points
> (coeff=op.laplacianCoefficients(0,0)+...) with:
> HEAP ERROR: Array_Data_Pointer == NULL in double* MDI_double_Allocate (Size
> = 79361856)!
>
> I understand the matrix is stored in sparse format, so I would assume the
> size of the problem to be still manageable even in the serial environment.
>
> Any ideas greatly welcome,
>
> Petr
>
>
>
>
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