AMReX_SpMatUtil.H

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#ifndef AMREX_SPMAT_UTIL_H_
#define AMREX_SPMAT_UTIL_H_
#include <AMReX_Config.H>
 
#include <AMReX_SpMatrix.H>
 
namespace amrex {
 
template <typename T, template <typename> class V>
CSR<T,V> transpose (CSR<T,V> const& csr, Long ncols)
{
    Long nnz = csr.nnz;
 
    CSR<T,V> csrt;
    csrt.mat.resize(nnz);
    csrt.col_index.resize(nnz);
    csrt.row_offset.resize(ncols+1);
    csrt.nnz = nnz;
 
    detail::transpose(csrt.view(), csr.const_view());
 
    return csrt;
}
 
template <typename T, template<typename> class Allocator>
SpMatrix<T,Allocator> transpose (SpMatrix<T,Allocator> const& A,
                                 AlgPartition col_partition)
{
    const_cast<SpMatrix<T,Allocator>&>(A).startComm_tr(col_partition);
 
    SpMatrix<T,Allocator> AT;
    AT.m_row_begin = col_partition[ParallelDescriptor::MyProc()];
    AT.m_row_end   = col_partition[ParallelDescriptor::MyProc()+1];
    AT.m_partition = std::move(col_partition);
    AT.m_nnz       = A.m_csr.nnz;
 
    // transpose the diagonal part
    auto at_csr = transpose(A.m_csr, AT.numLocalRows());
    AT.m_csr = std::move(at_csr);
 
    const_cast<SpMatrix<T,Allocator>&>(A).finishComm_tr(AT);
 
    return AT;
}
 
}
 
#endif