LAPACKReplacement.cpp

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/*
 *      This file is part of qpOASES.
 *
 *      qpOASES -- An Implementation of the Online Active Set Strategy.
 *      Copyright (C) 2007-2011 by Hans Joachim Ferreau, Andreas Potschka,
 *      Christian Kirches et al. All rights reserved.
 *
 *      qpOASES is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation; either
 *      version 2.1 of the License, or (at your option) any later version.
 *
 *      qpOASES is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *      See the GNU Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public
 *      License along with qpOASES; if not, write to the Free Software
 *      Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */


#include <math.h>


extern "C" void dpotrf_ (const char *uplo, const unsigned long *_n, double *a,
                                                 const unsigned long *_lda, long *info)
{
        unsigned long n = *_n, lda = *_lda;
        double sum;
        unsigned long i, j;
        int k;

        for( i=0; i<n; ++i )
        {
                /* j == i */
                sum = a[i + lda*i];

                for( k=(i-1); k>=0; --k )
                        sum -= a[k+lda*i] * a[k+lda*i];

                if ( sum > 0.0 )
                        a[i+lda*i] = sqrt( sum );
                else
                {
                        if (info != 0)
                                *info = i+1;
                        return;
                }

                for( j=(i+1); j<n; ++j )
                {
                        sum = a[j*lda + i];

                        for( k=(i-1); k>=0; --k )
                                sum -= a[k+lda*i] * a[k+lda*j];

                        a[i+lda*j] = sum / a[i+lda*i];
                }
        }
        if (info != 0)
                *info = 0;
}


/*extern "C" void spotrf_ (const char *uplo, const unsigned long *n, double *a,
                                                 const unsigned long *lda, long *info)
{

}*/