gemv.h

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#ifndef TATOOINE_BLAS_GEMV_H
#define TATOOINE_BLAS_GEMV_H
//==============================================================================
extern "C" {
//==============================================================================
auto dgemv_(char* TRANS, int* M, int* N, double* ALPHA, double* A, int* LDA,
            double* X, int* INCX, double* BETA, double* Y, int* INCY) -> void;
auto sgemv_(char* TRANS, int* M, int* N, float* ALPHA, float* A, int* LDA,
            float* X, int* INCX, float* BETA, float* Y, int* INCY) -> void;
//==============================================================================
}
//==============================================================================
#include <tatooine/blas/base.h>
 
#include <cassert>
//==============================================================================
namespace tatooine::blas {
//==============================================================================
//==============================================================================
template <std::floating_point Float>
auto gemv(op TRANS, int M, int N, Float ALPHA, Float const* A, int LDA,
          Float const* X, int INCX, Float BETA, Float* Y, int INCY) -> void {
  if constexpr (std::same_as<Float, double>) {
    dgemv_(reinterpret_cast<char*>(&TRANS), &M, &N, &ALPHA,
           const_cast<Float*>(A), &LDA, const_cast<Float*>(X), &INCX, &BETA, Y,
           &INCY);
  } else if constexpr (std::same_as<Float, float>) {
    sgemv_(reinterpret_cast<char*>(&TRANS), &M, &N, &ALPHA,
           const_cast<Float*>(A), &LDA, const_cast<Float*>(X), &INCX, &BETA, Y,
           &INCY);
  }
}
//==============================================================================
template <typename Real>
auto gemv(op trans, Real const alpha, tensor<Real> const& A,
          tensor<Real> const& x, Real const beta, tensor<Real>& y) {
  assert(A.rank() == 2);
  assert(x.rank() == 1);
  assert(y.rank() == 1);
  auto const M = A.dimension(0);
  auto const N = A.dimension(1);
  assert(N == x.dimension(0));
  assert(y.dimension(0) == M);
 
  return gemv(trans, static_cast<int>(M), static_cast<int>(N), alpha, A.data(),
              static_cast<int>(M), x.data(), 1, beta, y.data(), 1);
}
//------------------------------------------------------------------------------
template <typename Real>
auto gemv(Real const alpha, tensor<Real> const& A, tensor<Real> const& x,
          Real const beta, tensor<Real>& y) {
  return gemv(op::no_transpose, alpha, A, x, beta, y);
}
//==============================================================================
}  // namespace tatooine::blas
//==============================================================================
#endif