Magma crashes when i want to solve One milion matrix

Open discussion for MAGMA library (Matrix Algebra on GPU and Multicore Architectures)
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Joined: Wed May 10, 2017 11:01 pm

Magma crashes when i want to solve One milion matrix

Post by leo777 » Wed May 10, 2017 11:24 pm

I have a tesla C2075 with 6GB of memory and i want to solve big matrix sparse with one million of unknowns. But when the program is running magma crashes. Terminal shows a segmentation fault. I dont know why, because GPU memory is enough to do that and much more. I'm wondering if someone here solves linear system equations greater than one million of unknowns. If I select "ten thousand unknowns" there is no problem, the problem is when i increase the number of unknowns. Thanks in advance for your responses.


My code is this (only I copy and paste from example dir)

magma_d_mtransfer(A_h, &A_d, Magma_CPU, Magma_DEV, queue);
magma_d_mtransfer(b_h, &b_d, Magma_CPU, Magma_DEV, queue);
magma_d_mtransfer(x_h, &x_d, Magma_CPU, Magma_DEV, queue);

// Choose a solver, preconditioner, etc. - see documentation for options.
opts.solver_par.solver = Magma_PBICGSTAB; // _PIDRMERGE _PBICGSTAB _PGMRES
// opts.solver_par.restart = 10;
opts.solver_par.maxiter = 1000;
opts.solver_par.rtol = tolerance_press;
opts.precond_par.solver = Magma_ILU;
// opts.precond_par.maxiter = 1000;
opts.precond_par.levels = 0;
opts.precond_par.trisolver = Magma_CUSOLVE;

// Initialize the solver.
magma_dsolverinfo_init( &opts.solver_par, &opts.precond_par, queue );

magma_d_precondsetup( A_d, b_d, &opts.solver_par, &opts.precond_par, queue );
// My code crashes here, there is a segmentation fault :(
magma_d_solver( A_d, b_d, &x_d, &opts, queue );

magma_d_mtransfer( x_d, &x_h, Magma_DEV, Magma_CPU, queue );

// and back to the application code
magma_dvget( x_h, &m, &n, &deltaPV, queue );

magma_dsolverinfo_free( &opts.solver_par, &opts.precond_par, queue );

magma_d_mfree( &x_d, queue );
magma_d_mfree( &b_d, queue );
magma_d_mfree( &A_d, queue );

hartwig anzt
Posts: 90
Joined: Tue Sep 02, 2014 5:44 pm

Re: Magma crashes when i want to solve One milion matrix

Post by hartwig anzt » Thu May 11, 2017 2:03 am

Dear leo777,

as you point out that the code works for some matrices, and I don't have a matrix at hand where it does not work, it is a bit difficult for me to identify the problem. Maybe you could provide me access to the problem where the whole thing crashes? (Google-Drive, Dropbox, fileshare) Alternatively, if the system has to be kept confidential, maybe you can at least provide me with some key characteristics like n, nnz, and a sparsity pattern screenshot?

I am happy to help!

Thanks, Hartwig

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