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/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2014 Abhinav Baid
******************************************************************************/
#include "d_mat.h"
void
d_mat_gso(d_mat_t B, const d_mat_t A)
{
slong i, j, k, flag;
double t, s;
if (B->r != A->r || B->c != A->c)
{
flint_printf("Exception (d_mat_gso). Incompatible dimensions.\n");
abort();
}
if (B == A)
{
d_mat_t t;
d_mat_init(t, A->r, A->c);
d_mat_gso(t, A);
d_mat_swap(B, t);
d_mat_clear(t);
return;
}
if (A->r == 0)
{
return;
}
for (k = 0; k < A->c; k++)
{
for (j = 0; j < A->r; j++)
{
d_mat_entry(B, j, k) = d_mat_entry(A, j, k);
}
flag = 1;
while (flag)
{
t = 0;
for (i = 0; i < k; i++)
{
s = 0;
for (j = 0; j < A->r; j++)
{
s += d_mat_entry(B, j, i) * d_mat_entry(B, j, k);
}
t += s * s;
for (j = 0; j < A->r; j++)
{
d_mat_entry(B, j, k) -= s * d_mat_entry(B, j, i);
}
}
s = 0;
for (j = 0; j < A->r; j++)
{
s += d_mat_entry(B, j, k) * d_mat_entry(B, j, k);
}
t += s;
flag = 0;
if (s < t)
{
if (s * D_EPS == 0)
s = 0;
else
flag = 1;
}
}
s = sqrt(s);
if (s != 0)
s = 1 / s;
for (j = 0; j < A->r; j++)
{
d_mat_entry(B, j, k) *= s;
}
}
}
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