[Trilinos-Users] performance of trilinos

[Andrey Prokopenko]

Hi  Chen-Liang ,

This code cannot be compiled. For instance, the prototype of get_neighbors
requires "int" as a first argument, but in the body of the main
MyGlobalElements pointer is passed. Similar with A.InsertGlobalValues.

Are there misprints around during some copy/paste?

Andrey

On Tue, Aug 21, 2012 at 8:38 PM, chenliang wang <hi181904665 at msn.com> wrote:

>
> Hi,
> I use the code listed at the end of this mail to test the speedup using
> Trilinos (10.10.2 compiled with mkl) in our DELL cluster.To my surprise,
> there is no significant speedup no matter how many processors I use.(almost
> 1.5x~1.2x)
> Is that possible? Is there any more rough benchmarks to compare the
> speedup ?
>
> Chen-Liang Wang
>
>
> ***********************************************************************************************************************************************************************************************************************************************************************
> //the example code:
> // Solve a 2D Laplacian problem
> // This example builds the matrix and solves it with AztecOO.
> #include "Epetra_ConfigDefs.h"
> #ifdef HAVE_MPI
> #include "mpi.h"
> #include "Epetra_MpiComm.h"
> #else
> #include "Epetra_SerialComm.h"
> #endif
> #include "Epetra_Map.h"
> #include "Epetra_Vector.h"
> #include "Epetra_CrsMatrix.h"
> #include "AztecOO.h"
>
> // external function
> void get_neighbours( const int i, const int nx, const int ny,
>               int & left, int & right,
>               int & lower, int & upper);
>
> // =========== //
> // main driver //
> // =========== //
>
> int main(int argc, char *argv[])
> {
>
> #ifdef HAVE_MPI
> MPI_Init(&argc, &argv);
> Epetra_MpiComm Comm(MPI_COMM_WORLD);
> #else
> Epetra_SerialComm Comm;
> #endif
>
> // number of nodes along the x- and y-axis
> int nx = 4806;
> int ny = 4046;
> int NumGlobalElements = nx * ny;
>
> // create a linear map
> Epetra_Map Map(NumGlobalElements,0,Comm);
>
> // local number of rows
> int NumMyElements = Map.NumMyElements();
> // get update list
> int * MyGlobalElements = new int [NumMyElements];
> Map.MyGlobalElements( MyGlobalElements );
>
> // Create a Epetra_Matrix with 5 nonzero per rows
>
> Epetra_CrsMatrix A(Copy,Map,5);
>
> // Add rows one-at-a-time
> // Need some vectors to help
>
> double Values[4];
> int Indices[4];
> int NumEntries;
> int left, right, lower, upper;
> double diag = 4.0;
>
> for( int i=0 ; i<NumMyElements; ++i ) {
>     int NumEntries=0;
>     get_neighbours( MyGlobalElements, nx, ny,
>              left, right, lower, upper);
>     if( left != -1 ) {
>     Indices[NumEntries] = left;
>     Values[NumEntries] = -1.0;
>     ++NumEntries;
>     }
>     if( right != -1 ) {
>       Indices[NumEntries] = right;
>       Values[NumEntries] = -1.0;
>       ++NumEntries;
>     }
>     if( lower != -1 ) {
>       Indices[NumEntries] = lower;
>       Values[NumEntries] = -1.0;
>       ++NumEntries;
>     }
>     if( upper != -1 ) {
>       Indices[NumEntries] = upper;
>       Values[NumEntries] = -1.0;
>       ++NumEntries;
>     }
>     // put the off-diagonal entries
>     A.InsertGlobalValues(MyGlobalElements, NumEntries, Values, Indices);
>     // Put in the diagonal entry
>     A.InsertGlobalValues(MyGlobalElements, 1, &diag, MyGlobalElements+i);
> }
>
> // Finish up
> A.FillComplete();
>
> // create x and b vectors
> Epetra_Vector x(Map);
> Epetra_Vector b(Map);
> //b.PutScalar(100.0);
> b.Random();
> x.Random();
> // ==================== AZTECOO INTERFACE ======================
>
> // create linear problem  Ax=b
> Epetra_LinearProblem Problem(&A,&x,&b);
> // create AztecOO instance
> AztecOO Solver(Problem);
>
> Solver.SetAztecOption( AZ_precond, AZ_none );//
> //Solver.SetAztecOption( AZ_precond, AZ_Jacobi );//Jacobi
> Solver.SetAztecOption( AZ_solver, AZ_cg );//CG
> //Solver.SetAztecOption( AZ_solver, AZ_gmres );//
> Solver.SetAztecOption(AZ_output,AZ_all);//
> Solver.Iterate(100,1E-4);//
>
> // ==================== END OF AZTECOO INTERFACE ================
>
> if( Comm.MyPID() == 0 ) {
>     cout << "Solver performed " << Solver.NumIters()
>     << "iterations.\n";
>     cout << "Norm of the true residual = " << Solver.TrueResidual() <<
> endl;
> }
>
> #ifdef HAVE_MPI
> MPI_Finalize();
> #endif
>
> return(EXIT_SUCCESS);
>
> }
>
>
> /****************************************************************************/
>
> /****************************************************************************/
>
> /****************************************************************************/
>
> void get_neighbours( const int i, const int nx, const int ny,
>               int & left, int & right,
>               int & lower, int & upper)
> {
>
> int ix, iy;
> ix = i%nx;
> iy = (i - ix)/nx;
>
> if( ix == 0 )
>     left = -1;
> else
>     left = i-1;
> if( ix == nx-1 )
>     right = -1;
> else
>     right = i+1;
> if( iy == 0 )
>     lower = -1;
> else
>     lower = i-nx;
> if( iy == ny-1 )
>     upper = -1;
> else
>     upper = i+nx;
>
> return;
>
> }
>
>
>
> _______________________________________________
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> Trilinos-Users at software.sandia.gov
> http://software.sandia.gov/mailman/listinfo/trilinos-users
>
>
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