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// This is a simple standalone example. See README.txt
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "magma_v2.h"
#include "magmasparse.h"
// ------------------------------------------------------------
// This is an example how magma can be integrated into another software.
int main( int argc, char** argv )
{
// The software does e.g. discretization of a PDE,
// ends up with a sparse linear system in CSR format and a RHS.
// Let's assume this system is a diagonal system of size m.
int i, m=700, n=1;
double *rhs, *sol;
rhs = (double*) calloc(m, sizeof(double));
sol = (double*) calloc(m, sizeof(double));
for (i = 0; i < m; ++i) {
rhs[i] = 3.0;
sol[i] = 0.0;
}
// Initialize MAGMA and create some LA structures.
magma_init();
magma_dopts opts;
magma_queue_t queue;
magma_queue_create( 0, &queue );
magma_d_matrix b={Magma_CSR}, db={Magma_CSR};
magma_d_matrix x={Magma_CSR}, dx={Magma_CSR};
magma_d_matrix dA={Magma_CSR};
dA.num_rows = m;
dA.num_cols = m;
dA.memory_location = Magma_DEV;
// we do not have a system, we have an operator
dA.storage_type = Magma_SPMVFUNCTION;
// Pass the system to MAGMA.
magma_dvset( m, 1, rhs, &b, queue );
// Choose a solver, preconditioner, etc. - see documentation for options.
opts.solver_par.solver = Magma_CG;
opts.solver_par.maxiter = 1000;
opts.solver_par.rtol = 1e-4;
// Initialize the solver.
magma_dsolverinfo_init( &opts.solver_par, &opts.precond_par, queue );
// Copy the system to the device (optional, only necessary if using the GPU)
magma_dmtransfer( b, &db, Magma_CPU, Magma_DEV, queue );
// initialize an initial guess for the iteration vector
magma_dvinit( &dx, Magma_DEV, b.num_rows, b.num_cols, 0.0, queue );
// If we want to solve the problem, we run:
magma_d_solver( dA, db, &dx, &opts, queue );
printf("iterations: %d residual: %.4e\nvalues:\n", opts.solver_par.numiter, opts.solver_par.iter_res );
// Then copy the solution back to the host...
magma_dmtransfer( dx, &x, Magma_DEV, Magma_CPU, queue );
// and back to the application code
magma_dvcopy( x, &m, &n, sol, queue );
// Free the allocated memory...
magma_dmfree( &dx, queue );
magma_dmfree( &db, queue );
magma_dmfree( &dA, queue );
magma_dmfree( &b, queue ); // won't do anything as MAGMA does not own the data.
// and finalize MAGMA.
magma_queue_destroy( queue );
magma_finalize();
// From here on, the application code may continue with the solution in sol...
for (i = 0; i < 20; ++i) {
printf("%.4f\n", sol[i]);
}
return 0;
}
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