CFD/hypre
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modified the standard matvec to take advantage of the rownnz pointer

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IF the number of nonzero rows (num_rownnz) is less than the number of
rows. Otherwise the matvec is carried out without any change.
This commit is contained in:
castilla 2002-06-25 02:04:41 +00:00
parent 9c8a4af953
commit 9293f196a7
1 changed files with 32 additions and 6 deletions
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38
seq_mv/csr_matvec.c
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@ -31,6 +31,9 @@ hypre_CSRMatrixMatvec( double alpha,
int num_rows = hypre_CSRMatrixNumRows(A);
int num_cols = hypre_CSRMatrixNumCols(A);
int *A_rownnz = hypre_CSRMatrixRownnz(A);
int num_rownnz = hypre_CSRMatrixNumRownnz(A);
double *x_data = hypre_VectorData(x);
double *y_data = hypre_VectorData(y);
int x_size = hypre_VectorSize(x);
@ -38,7 +41,11 @@ hypre_CSRMatrixMatvec( double alpha,
double temp;
int i, jj;
int i, j, jj;
int m;
double xpar=0.7;
int ierr = 0;
@ -106,12 +113,31 @@ hypre_CSRMatrixMatvec( double alpha,
#define HYPRE_SMP_PRIVATE i,jj
#include "../utilities/hypre_smp_forloop.h"
for (i = 0; i < num_rows; i++)
/* use rownnz pointer to do the A*x multiplication when num_rownnz is smaller than num_rows */
if (num_rownnz < xpar*(num_rows))
{
temp = y_data[i];
for (jj = A_i[i]; jj < A_i[i+1]; jj++)
temp += A_data[jj] * x_data[A_j[jj]];
y_data[i] = temp;
for (i = 0; i < num_rownnz; i++)
{
m = A_rownnz[i];
for (jj = A_i[m]; jj < A_i[m+1]; jj++)
{
j = A_j[jj];
y_data[m] += A_data[jj] * x_data[j];
}
}
}
else
{
for (i = 0; i < num_rows; i++)
{
temp = y_data[i];
for (jj = A_i[i]; jj < A_i[i+1]; jj++)
temp += A_data[jj] * x_data[A_j[jj]];
y_data[i] = temp;
}
}
/*-----------------------------------------------------------------