[petsc-users] F90 to petsc 3.4.3 interface - loss of accuracy

[Barry Smith]

> On Jan 28, 2015, at 12:39 PM, <Carol.Brickley at awe.co.uk> <Carol.Brickley at awe.co.uk> wrote:
> 
> Hi,
>  
> Does anyone find loss of accuracy between F90 code and Petsc 3.4.3 C codes? I am noticing that some of my data is returning 9.99999997e-13 instead of 1.00000000e-12 for example.

  I am not sure exactly what your question is. Do you have two codes a F90 code without PETSc and a PETSc based C code? What is the data that is different? Is it solutions, residual values, ...?  This kind of small difference can often be caused by different tolerances used during the iterative solvers. We'll need more information in order to make any suggestions.

   Barry

>  
> Carol
>  
> Dr Carol Brickley 
> BSc,PhD,ARCS,DIC,MBCS
>  
> Senior Software Engineer
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