blis/frame/include/bli_trsm_small_ref.h

/*

   BLIS
   An object-based framework for developing high-performance BLAS-like
   libraries.

   Copyright (C) 2023 - 2024, Advanced Micro Devices, Inc. All rights reserved.

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   met:
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      notice, this list of conditions and the following disclaimer.
    - Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    - Neither the name(s) of the copyright holder(s) nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

#ifdef BLIS_ENABLE_TRSM_PREINVERSION
  #define DIAG_ELE_INV_OPS(a, b) (a / b)
  #define DIAG_ELE_EVAL_OPS(a, b) (a * b)
#endif

#ifdef BLIS_DISABLE_TRSM_PREINVERSION
  #define DIAG_ELE_INV_OPS(a, b) (a * b)
  #define DIAG_ELE_EVAL_OPS(a, b) (a / b)
#endif

// reference code for LUTN
BLIS_INLINE err_t dtrsm_AutXB_ref
   (
      double *A,
      double *B,
      dim_t M,
      dim_t N,
      dim_t lda,
      dim_t ldb,
      bool unitDiagonal
   )
{
  dim_t i, j, k;
  for (k = 0; k < M; k++)
  {
    double lkk_inv = 1.0;
    if (!unitDiagonal)
      lkk_inv = DIAG_ELE_INV_OPS(lkk_inv, A[k + k * lda]);
    for (j = 0; j < N; j++)
    {
      B[k + j * ldb] = DIAG_ELE_EVAL_OPS(B[k + j * ldb], lkk_inv);
      for (i = k + 1; i < M; i++)
      {
        B[i + j * ldb] -= A[i * lda + k] * B[k + j * ldb];
      }
    }
  } // k -loop
  return BLIS_SUCCESS;
}

// reference code for LLNN
BLIS_INLINE err_t dtrsm_AlXB_ref
   (
      double *A,
      double *B,
      dim_t M,
      dim_t N,
      dim_t lda,
      dim_t ldb,
      bool is_unitdiag
    )
{
  dim_t i, j, k;
  for (k = 0; k < M; k++)
  {
    double lkk_inv = 1.0;
    if (!is_unitdiag)
      lkk_inv = DIAG_ELE_INV_OPS(lkk_inv, A[k + k * lda]);
    for (j = 0; j < N; j++)
    {
      B[k + j * ldb] = DIAG_ELE_EVAL_OPS(B[k + j * ldb], lkk_inv);
      for (i = k + 1; i < M; i++)
      {
        B[i + j * ldb] -= A[i + k * lda] * B[k + j * ldb];
      }
    }
  } // k -loop
  return BLIS_SUCCESS;
}

// reference code for LUNN
BLIS_INLINE err_t dtrsm_AuXB_ref
   (
     double *A,
     double *B,
     dim_t M,
     dim_t N,
     dim_t lda,
     dim_t ldb,
     bool is_unitdiag
   )
{
  dim_t i, j, k;
  for (k = M - 1; k >= 0; k--)
  {
    double lkk_inv = 1.0;
    if (!is_unitdiag)
      lkk_inv = DIAG_ELE_INV_OPS(lkk_inv, A[k + k * lda]);
    for (j = N - 1; j >= 0; j--)
    {
      B[k + j * ldb] = DIAG_ELE_EVAL_OPS(B[k + j * ldb], lkk_inv);
      for (i = k - 1; i >= 0; i--)
      {
        B[i + j * ldb] -= A[i + k * lda] * B[k + j * ldb];
      }
    }
  } // k -loop
  return BLIS_SUCCESS;
} // end of function

// reference code for LLTN
BLIS_INLINE err_t dtrsm_AltXB_ref
   (
     double *A,
     double *B,
     dim_t M,
     dim_t N,
     dim_t lda,
     dim_t ldb,
     bool is_unitdiag
   )
{
  dim_t i, j, k;
  for (k = M - 1; k >= 0; k--)
  {
    double lkk_inv = 1.0;
    if (!is_unitdiag)
      lkk_inv = DIAG_ELE_INV_OPS(lkk_inv, A[k + k * lda]);
    for (j = N - 1; j >= 0; j--)
    {
      B[k + j * ldb] = DIAG_ELE_EVAL_OPS(B[k + j * ldb], lkk_inv);
      for (i = k - 1; i >= 0; i--)
      {
        B[i + j * ldb] -= A[i * lda + k] * B[k + j * ldb];
      }
    }
  } // k -loop
  return BLIS_SUCCESS;
} // end of function