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Tpetra_Details_scaleBlockDiagonal.hpp
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41 
42 #ifndef TPETRA_DETAILS_SCALEBLOCKDIAGONAL_HPP
43 #define TPETRA_DETAILS_SCALEBLOCKDIAGONAL_HPP
44 
45 #include "TpetraCore_config.h"
46 #include "Tpetra_CrsMatrix.hpp"
47 #include "Teuchos_ScalarTraits.hpp"
49 #include "KokkosBatched_Util.hpp"
50 #include "KokkosBatched_LU_Decl.hpp"
51 #include "KokkosBatched_LU_Serial_Impl.hpp"
52 #include "KokkosBatched_Trsm_Decl.hpp"
53 #include "KokkosBatched_Trsm_Serial_Impl.hpp"
54 
55 
62 
63 namespace Tpetra {
64 namespace Details {
65 
66 
67 template<class MultiVectorType>
68 void inverseScaleBlockDiagonal(const MultiVectorType & blockDiagonal, bool doTranspose, MultiVectorType & multiVectorToBeScaled) {
69  using LO = typename MultiVectorType::local_ordinal_type;
70  using local_mv_type = typename MultiVectorType::dual_view_type::t_dev;
71  using range_type = Kokkos::RangePolicy<typename MultiVectorType::node_type::execution_space, LO>;
72  using namespace KokkosBatched;
73  typename MultiVectorType::impl_scalar_type SC_one = Teuchos::ScalarTraits<typename MultiVectorType::impl_scalar_type>::one();
74 
75  // Sanity checking: Map Compatibility (A's rowmap matches diagonal's map)
76  if (Tpetra::Details::Behavior::debug() == true) {
77  TEUCHOS_TEST_FOR_EXCEPTION(!blockDiagonal.getMap()->isSameAs(*multiVectorToBeScaled.getMap()),
78  std::runtime_error, "Tpetra::Details::scaledBlockDiagonal was given incompatible maps");
79  }
80 
81  LO numrows = blockDiagonal.getLocalLength();
82  LO blocksize = blockDiagonal.getNumVectors();
83  LO numblocks = numrows / blocksize;
84 
85  // Get Kokkos versions of objects
86  local_mv_type blockDiag = blockDiagonal.getLocalViewDevice();
87  local_mv_type toScale = multiVectorToBeScaled.getLocalViewDevice();
88 
89  typedef Algo::Level3::Unblocked algo_type;
90  Kokkos::parallel_for("scaleBlockDiagonal",range_type(0,numblocks),KOKKOS_LAMBDA(const LO i){
91  Kokkos::pair<LO,LO> row_range(i*blocksize,(i+1)*blocksize);
92  auto A = Kokkos::subview(blockDiag,row_range, Kokkos::ALL());
93  auto B = Kokkos::subview(toScale, row_range, Kokkos::ALL());
94 
95  // Factor
96  SerialLU<algo_type>::invoke(A);
97 
98  if(doTranspose) {
99  // Solve U^T
100  SerialTrsm<Side::Left,Uplo::Upper,Trans::Transpose,Diag::NonUnit,algo_type>::invoke(SC_one,A,B);
101  // Solver L^T
102  SerialTrsm<Side::Left,Uplo::Lower,Trans::Transpose,Diag::Unit,algo_type>::invoke(SC_one,A,B);
103  }
104  else {
105  // Solve L
106  SerialTrsm<Side::Left,Uplo::Lower,Trans::NoTranspose,Diag::Unit,algo_type>::invoke(SC_one,A,B);
107  // Solve U
108  SerialTrsm<Side::Left,Uplo::Upper,Trans::NoTranspose,Diag::NonUnit,algo_type>::invoke(SC_one,A,B);
109  }
110  });
111 }
112 
113 } // namespace Details
114 } // namespace Tpetra
115 
116 #endif // TPETRA_DETAILS_SCALEBLOCKDIAGONAL_HPP
static bool debug()
Whether Tpetra is in debug mode.
Declaration of Tpetra::Details::Behavior, a class that describes Tpetra&#39;s behavior.