That's way off. It should be of the order of 1e-8 or lower.
Take that system and solve it as a 1 x 1 system and see what you get. Or
try it in another linear solver on a single processor. There's lots of
free solvers for small systems out there. Check the numbers from that
from the numbers coming out of Scalapack and track it back from there.
One other thing, this isn't really a LAM question. This example is very
well covered in the SCALAPACK docs, which you should read.
Damien
> i m trying to run an exmple code of scalapack for testing..but i m getting
> the error .....
>
> the configuration of Pc is 3.6 GHz, 2GB RAM fedora-3 kernal 2.6.9-1.667smp
> each.....
>
> for compilation of the code as
>
> mpif77 example.f \
> /usr/local/include/libscalapack.a \
> /usr/local/include/blacsF77init_MPI-LINUX-0.a \
> /usr/local/include/blacs_MPI-LINUX-0.a \
> /usr/local/include/blacsF77init_MPI-LINUX-0.a \
> /usr/local/include/blas_LINUX.a
>
> after this i have given the command for run like
> mpirun N a.out
> where N=4
> the result comes out to be
>
> ScaLAPACK Example Program #1 -- May 1, 1997
>
> Solving Ax=b where A is a 9 by 9 matrix with a block size of 2
> Running on 4 processes, where the process grid is 2 by 2
>
> INFO code returned by PDGESV = 8
>
> According to the normalized residual the solution is incorrect.
>
> ||A*x - b|| / ( ||x||*||A||*eps*N ) = 4.64139092E+14
>
>
> what are the reasons for the solution to be incorrect....that is not
> empasised with the example code....as i m new with this parallelization
> options...please help me out of this....
> tia
> ravi
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