trtrs.h

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#ifndef TATOOINE_LAPACK_TRTRS_H
#define TATOOINE_LAPACK_TRTRS_H
//==============================================================================
extern "C" {
auto dtrtrs_(char* UPLO, char* TRANS, char* DIAG, int* N, int* NRHS, double* A,
             int* LDA, double* B, int* LDB, int* INFO) -> void;
//------------------------------------------------------------------------------
auto strtrs_(char* UPLO, char* TRANS, char* DIAG, int* N, int* NRHS, float* A,
             int* LDA, float* B, int* LDB, int* INFO) -> void;
}
//==============================================================================
#include <concepts>
#include <tatooine/lapack/base.h>
//==============================================================================
namespace tatooine::lapack {
//==============================================================================
template <std::floating_point Float>
auto trtrs(uplo u, op t, diag d, int N, int NRHS, Float* A, int LDA,
           Float* B, int LDB) -> int {
  auto INFO = int{};
  if constexpr (std::same_as<Float, double>) {
    dtrtrs_(reinterpret_cast<char*>(&u), reinterpret_cast<char*>(&t),
            reinterpret_cast<char*>(&d), &N, &NRHS, A, &LDA, B, &LDB, &INFO);
  } else if constexpr (std::same_as<Float, float>) {
    strtrs_(reinterpret_cast<char*>(&u), reinterpret_cast<char*>(&t),
            reinterpret_cast<char*>(&d), &N, &NRHS, A, &LDA, B, &LDB, &INFO);
  }
  return INFO;
}
//==============================================================================
//==============================================================================
template <typename T, size_t M, size_t N, size_t NRHS>
auto trtrs(tensor<T, M, N>& A, tensor<T, M, NRHS>& B, uplo const u,
           op const t, diag const d) {
  return trtrs(u, t, d, static_cast<int>(N), static_cast<int>(NRHS), A.data(),
               static_cast<int>(M), B.data(), static_cast<int>(M));
}
//------------------------------------------------------------------------------
template <typename T, size_t M, size_t N>
auto trtrs(tensor<T, M, N>& A, tensor<T, M>& b, uplo const u,
           op const t, diag const d) {
  return trtrs(u, t, d, static_cast<int>(N), 1, A.data(), static_cast<int>(M),
               b.data(), static_cast<int>(M));
}
//------------------------------------------------------------------------------
template <typename T>
auto trtrs(tensor<T>& A, tensor<T>& B, uplo const u,
           op const t,  diag const d) {
  assert(A.rank() == 2);
  assert(B.rank() == 1 || B.rank() == 2);
  assert(A.dimension(0) == B.dimension(0));
  auto const M    = A.dimension(0);
  auto const N    = A.dimension(1);
  auto const NRHS = B.rank() == 2 ? B.dimension(1) : 1;
  return trtrs(u, t, d, static_cast<int>(N), static_cast<int>(NRHS), A.data(),
               static_cast<int>(M), B.data(), static_cast<int>(M));
}
//==============================================================================
//==============================================================================
}  // namespace tatooine::lapack
//==============================================================================
#endif