clapack_sgetrf.c

来自「基于Blas CLapck的.用过的人知道是干啥的」· C语言 代码 · 共 113 行

/*
 *             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.
 *
 */

#define SREAL
#include "atlas_misc.h"
#include "atlas_lapack.h"
#include "clapack.h"

int clapack_sgetrf(const enum CBLAS_ORDER Order, const int M, const int N,
                   float *A, const int lda, int *ipiv)
/*
 * Computes one of two LU factorizations based on the setting of the Order
 * parameter, as follows:
 * ----------------------------------------------------------------------------
 *                       Order == CblasColMajor
 * Column-major factorization of form
 *   A = P * L * U
 * where P is a row-permutation matrix, L is lower triangular with unit
 * diagonal elements (lower trapazoidal if M > N), and U is upper triangular
 * (upper trapazoidal if M < N).
 *
 * ----------------------------------------------------------------------------
 *                       Order == CblasRowMajor
 * Row-major factorization of form
 *   A = P * L * U
 * where P is a column-permutation matrix, L is lower triangular (lower
 * trapazoidal if M > N), and U is upper triangular with unit diagonals (upper
 * trapazoidal if M < N).
 *
 * ============================================================================
 * Let IERR be the return value of the function:
 *    If IERR == 0, successful exit.
 *    If (IERR < 0) the -IERR argument had an illegal value
 *    If (IERR > 0 && Order == CblasColMajor)
 *       U(i-1,i-1) is exactly zero.  The factorization has been completed,
 *       but the factor U is exactly singular, and division by zero will
 *       occur if it is used to solve a system of equations.
 *    If (IERR > 0 && Order == CblasRowMajor)
 *       L(i-1,i-1) is exactly zero.  The factorization has been completed,
 *       but the factor L is exactly singular, and division by zero will
 *       occur if it is used to solve a system of equations.
 */
{
   int ierr=0;
   if (Order != CblasRowMajor && Order != CblasColMajor)
   {
      ierr = -1;
      cblas_xerbla(1, "clapack_sgetrf",
                   "Order must be %d or %d, but is set to %d\n",
                   CblasRowMajor, CblasColMajor, Order);
   }
   if (M < 0)
   {
      ierr = -2;
      cblas_xerbla(2, "clapack_sgetrf",
                   "M cannot be less than zero 0,; is set to %d.\n", M);
   }
   if (N < 0)
   {
      ierr = -3;
      cblas_xerbla(3, "clapack_sgetrf",
                   "N cannot be less than zero 0,; is set to %d.\n", N);
   }
   if (Order == CblasColMajor)
   {
      if (lda < M || lda < 1)
      {
         ierr = -6;
         cblas_xerbla(6, "clapack_sgetrf",
                      "lda must be >= MAX(M,1): lda=%d M=%d\n", lda, M);
      }
   }
   else
   {
      if (lda < N || lda < 1)
      {
         ierr = -6;
         cblas_xerbla(6, "clapack_sgetrf",
                      "lda must be >= MAX(N,1): lda=%d N=%d\n", lda, N);
      }
   }
   if (!ierr) ierr = ATL_getrf(Order, M, N, A, lda, ipiv);
   return(ierr);
}