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#include <cusp/csr_matrix.h>
#include <cusp/print.h>
int main(void)
{
// define array container types
typedef cusp::array1d<int, cusp::device_memory> IndexArray;
typedef cusp::array1d<float, cusp::device_memory> ValueArray;
// define array view types
typedef typename cusp::array1d_view<IndexArray::iterator> IndexArrayView;
typedef typename cusp::array1d_view<ValueArray::iterator> ValueArrayView;
// matrix dimensions
int num_rows = 4;
int num_cols = 3;
int num_entries = 6;
// allocate storage for (4,3) matrix with 6 nonzeros
IndexArray row_offsets(num_rows + 1);
IndexArray column_indices(num_entries);
ValueArray values(num_entries);
// initialize matrix data
row_offsets[0] = 0; // first offset is always zero
row_offsets[1] = 2;
row_offsets[2] = 2;
row_offsets[3] = 3;
row_offsets[4] = 6; // last offset is always num_entries
column_indices[0] = 0; values[0] = 10;
column_indices[1] = 2; values[1] = 20;
column_indices[2] = 2; values[2] = 30;
column_indices[3] = 0; values[3] = 40;
column_indices[4] = 1; values[4] = 50;
column_indices[5] = 2; values[5] = 60;
// define csr_matrix_view type
typedef cusp::csr_matrix_view<IndexArrayView, IndexArrayView, ValueArrayView> View;
// create a csr_matrix_view
View A(num_rows, num_cols, num_entries,
cusp::make_array1d_view(row_offsets),
cusp::make_array1d_view(column_indices),
cusp::make_array1d_view(values));
// create a csr_matrix_view like A but with different values
ValueArray other_values(6);
other_values[0] = 60;
other_values[1] = 50;
other_values[2] = 40;
other_values[3] = 30;
other_values[4] = 20;
other_values[5] = 10;
View B(num_rows, num_cols, num_entries,
cusp::make_array1d_view(row_offsets),
cusp::make_array1d_view(column_indices),
cusp::make_array1d_view(other_values));
// note that A and B are views to the same row_offsets and column_indices arrays
// A now represents the following matrix
// [10 0 20]
// [ 0 0 0]
// [ 0 0 30]
// [40 50 60]
// B now represents the following matrix
// [60 0 50]
// [ 0 0 0]
// [ 0 0 40]
// [30 20 10]
// print matrix entries
cusp::print(A);
cusp::print(B);
return 0;
}
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