atl_potrs.c

基于Blas CLapck的.用过的人知道是干啥的

/*
 *             Automatically Tuned Linear Algebra Software v3.8.0
 *                    (C) Copyright 1999 R. Clint Whaley
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *   2. 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.
 *   3. The name of the ATLAS group or the names of its contributers may
 *      not be used to endorse or promote products derived from this
 *      software without specific 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 ATLAS GROUP OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include "atlas_lapack.h"

#ifdef TCPLX
   #define MyTrans CblasConjTrans
#else
   #define MyTrans CblasTrans
#endif

void ATL_potrs(const enum CBLAS_ORDER Order, const enum CBLAS_UPLO Uplo,
               const int N, const int NRHS, const TYPE *A, const int lda,
               TYPE *B, const int ldb)
{
   #ifdef TCPLX
      int j;
      const int ldb2 = ldb+ldb;
      const TYPE one[2] = {ATL_rone, ATL_rzero};
   #else
      #define one ATL_rone
   #endif

   if (!N || !NRHS) return;
   if (Order == CblasColMajor)
   {
/*
 *    Solve X = inv(U) * inv(U') * B
 */
      if (Uplo == AtlasUpper)
      {
         cblas_trsm(Order, CblasLeft, CblasUpper, MyTrans, CblasNonUnit,
                    N, NRHS, one, A, lda, B, ldb);
         cblas_trsm(Order, CblasLeft, CblasUpper, CblasNoTrans, CblasNonUnit,
                    N, NRHS, one, A, lda, B, ldb);
      }
/*
 *    Solve X = inv(L') * inv(L) * B
 */
      else
      {
         cblas_trsm(Order, CblasLeft, CblasLower, CblasNoTrans, CblasNonUnit,
                    N, NRHS, one, A, lda, B, ldb);
         cblas_trsm(Order, CblasLeft, CblasLower, MyTrans, CblasNonUnit,
                    N, NRHS, one, A, lda, B, ldb);
      }
   }
/*
 * For row-major, remember we have x' and b', so we must transpose usual
 * equations
 */
   else
   {
      #ifdef TCPLX
         for (j=0; j < NRHS; j++)
            Mjoin(PATLU,scal)(N, -1.0, B+j*ldb2+1, 2);
      #endif
/*
 *    solve x^T = b^T * inv(U) * inv(U^T)
 *    conj( x^H = b^H * inv(U) * inv(U^H) )  (complex)
 */
      if (Uplo == CblasUpper)
      {
         cblas_trsm(Order, CblasRight, CblasUpper, CblasNoTrans, CblasNonUnit,
                    NRHS, N, one, A, lda, B, ldb);
         cblas_trsm(Order, CblasRight, CblasUpper, MyTrans, CblasNonUnit,
                    NRHS, N, one, A, lda, B, ldb);
      }
/*
 *    solve x^T = b^T * inv(L^T) * inv(L)
 *    conj( x^H = b^H * inv(L^H) * inv(L) )  (complex)
 */
      else
      {
         cblas_trsm(Order, CblasRight, CblasLower, MyTrans, CblasNonUnit,
                    NRHS, N, one, A, lda, B, ldb);
         cblas_trsm(Order, CblasRight, CblasLower, CblasNoTrans, CblasNonUnit,
                    NRHS, N, one, A, lda, B, ldb);
      }
      #ifdef TCPLX
         for (j=0; j < NRHS; j++)
            Mjoin(PATLU,scal)(N, -1.0, B+j*ldb2+1, 2);
      #endif
   }
}