SelfadjointMatrixVector_BLAS.h

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 ********************************************************************************
 *   Content : Eigen bindings to BLAS F77
 *   Selfadjoint matrix-vector product functionality based on ?SYMV/HEMV.
 ********************************************************************************
*/

#ifndef EIGEN_SELFADJOINT_MATRIX_VECTOR_BLAS_H
#define EIGEN_SELFADJOINT_MATRIX_VECTOR_BLAS_H

// IWYU pragma: private
#include "../InternalHeaderCheck.h"

namespace Eigen {

namespace internal {

/**********************************************************************
 * This file implements selfadjoint matrix-vector multiplication using BLAS
 **********************************************************************/

// symv/hemv specialization

template <typename Scalar, typename Index, int StorageOrder, int UpLo, bool ConjugateLhs, bool ConjugateRhs>
struct selfadjoint_matrix_vector_product_symv
    : selfadjoint_matrix_vector_product<Scalar, Index, StorageOrder, UpLo, ConjugateLhs, ConjugateRhs, BuiltIn> {};

#define EIGEN_BLAS_SYMV_SPECIALIZE(Scalar)                                                                           \
  template <typename Index, int StorageOrder, int UpLo, bool ConjugateLhs, bool ConjugateRhs>                        \
  struct selfadjoint_matrix_vector_product<Scalar, Index, StorageOrder, UpLo, ConjugateLhs, ConjugateRhs,            \
                                           Specialized> {                                                            \
    static void run(Index size, const Scalar* lhs, Index lhsStride, const Scalar* _rhs, Scalar* res, Scalar alpha) { \
      enum { IsColMajor = StorageOrder == ColMajor };                                                                \
      if (IsColMajor == ConjugateLhs) {                                                                              \
        selfadjoint_matrix_vector_product<Scalar, Index, StorageOrder, UpLo, ConjugateLhs, ConjugateRhs,             \
                                          BuiltIn>::run(size, lhs, lhsStride, _rhs, res, alpha);                     \
      } else {                                                                                                       \
        selfadjoint_matrix_vector_product_symv<Scalar, Index, StorageOrder, UpLo, ConjugateLhs, ConjugateRhs>::run(  \
            size, lhs, lhsStride, _rhs, res, alpha);                                                                 \
      }                                                                                                              \
    }                                                                                                                \
  };

EIGEN_BLAS_SYMV_SPECIALIZE(double)
EIGEN_BLAS_SYMV_SPECIALIZE(float)
EIGEN_BLAS_SYMV_SPECIALIZE(dcomplex)
EIGEN_BLAS_SYMV_SPECIALIZE(scomplex)

#define EIGEN_BLAS_SYMV_SPECIALIZATION(EIGTYPE, BLASTYPE, BLASFUNC)                                                \
  template <typename Index, int StorageOrder, int UpLo, bool ConjugateLhs, bool ConjugateRhs>                      \
  struct selfadjoint_matrix_vector_product_symv<EIGTYPE, Index, StorageOrder, UpLo, ConjugateLhs, ConjugateRhs> {  \
    typedef Matrix<EIGTYPE, Dynamic, 1, ColMajor> SYMVVector;                                                      \
                                                                                                                   \
    static void run(Index size, const EIGTYPE* lhs, Index lhsStride, const EIGTYPE* _rhs, EIGTYPE* res,            \
                    EIGTYPE alpha) {                                                                               \
      if (size == 0) return;                                                                                       \
      enum { IsRowMajor = StorageOrder == RowMajor ? 1 : 0, IsLower = UpLo == Lower ? 1 : 0 };                     \
      BlasIndex n = convert_index<BlasIndex>(size), lda = convert_index<BlasIndex>(lhsStride), incx = 1, incy = 1; \
      EIGTYPE beta(1);                                                                                             \
      const EIGTYPE* x_ptr;                                                                                        \
      char uplo = (IsRowMajor) ? (IsLower ? 'U' : 'L') : (IsLower ? 'L' : 'U');                                    \
      SYMVVector x_tmp;                                                                                            \
      if (ConjugateRhs) {                                                                                          \
        Map<const SYMVVector, 0> map_x(_rhs, size, 1);                                                             \
        x_tmp = map_x.conjugate();                                                                                 \
        x_ptr = x_tmp.data();                                                                                      \
      } else                                                                                                       \
        x_ptr = _rhs;                                                                                              \
      BLASFUNC(&uplo, &n, (const BLASTYPE*)&numext::real_ref(alpha), (const BLASTYPE*)lhs, &lda,                   \
               (const BLASTYPE*)x_ptr, &incx, (const BLASTYPE*)&numext::real_ref(beta), (BLASTYPE*)res, &incy);    \
    }                                                                                                              \
  };

#ifdef EIGEN_USE_MKL
EIGEN_BLAS_SYMV_SPECIALIZATION(double, double, dsymv)
EIGEN_BLAS_SYMV_SPECIALIZATION(float, float, ssymv)
EIGEN_BLAS_SYMV_SPECIALIZATION(dcomplex, MKL_Complex16, zhemv)
EIGEN_BLAS_SYMV_SPECIALIZATION(scomplex, MKL_Complex8, chemv)
#else
EIGEN_BLAS_SYMV_SPECIALIZATION(double, double, dsymv_)
EIGEN_BLAS_SYMV_SPECIALIZATION(float, float, ssymv_)
EIGEN_BLAS_SYMV_SPECIALIZATION(dcomplex, double, zhemv_)
EIGEN_BLAS_SYMV_SPECIALIZATION(scomplex, float, chemv_)
#endif

}  // end namespace internal

}  // end namespace Eigen

#endif  // EIGEN_SELFADJOINT_MATRIX_VECTOR_BLAS_H