Hi Jian,

Sorry for the slow response, this is grading time in the UK. 

This might be due to the preconditioners not being very smart in 2D. I think there might be a BlockDiagonal preconditioned in 2D which could possibly work much better. In 3D we have a number of preconditioners set up. 

I probably need to have a look at this but may not get a chance until you are over in a couple of weeks.

Cheers,
Spencer.

On 25 May 2016, at 02:04, Jian Yu <yuj@buaa.edu.cn> wrote:

Dear all,
I encountered a problem when I run the FieldConvert with two or more cpu cores for the C0Projection module.
For example, when I run the following command, it is OK:
mpirun -np 1 ./FieldConvert -m C0Projection 2D_20x20.xml 2D_20x20_0.chk 2D_20x20_0_C0.fld

However, the following command will report an error:
mpirun -np 2 ./FieldConvert -m C0Projection 2D_20x20.xml 2D_20x20_0.chk 2D_20x20_0_C0.fld 
and the error message is:

gs_setup: 60 unique labels shared
   pairwise times (avg, min, max): 0.000110245 0.00010879 0.000111699
   crystal router                : 9.22918e-05 9.22918e-05 9.22918e-05
   all reduce                    : 0.000179148 0.0001791 0.000179195
   used all_to_all method: crystal router
   handle bytes (avg, min, max): 4724 4724 4724
   buffer bytes (avg, min, max): 1920 1920 1920
CG iterations made = 5001 using tolerance of 1e-09 (error = nan, rhs_mag = inf)

Fatal   : Level 0 assertion violation
Exceeded maximum number of iterations
terminate called after throwing an instance of 'ErrorUtil::NekError'
  what():  Level 0 assertion violation
Exceeded maximum number of iterations


Can anyone help me about this?
Best 
Jian

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Spencer  Sherwin
McLaren Racing/Royal Academy of Engineering Research Chair, 
Professor of Computational Fluid Mechanics,
Department of Aeronautics,
Imperial College London
South Kensington Campus
London SW7 2AZ

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