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extern "C"{
#include <ldl.h>
}
#include <vector>
#include <map>
#include <algorithm>
#include <sparse_matrix.h>
class SystemLDL:SparseMatrix<double>{
private:
typedef std::map<IndexType,int> mapType;
std::vector<double> _B;
std::vector<double> _X;
std::vector<double> Lx,D,Y ;
std::vector<int> Li,Lp,Parent,Lnz,Flag,Pattern;
mapType _M;
public:
///allocate the resources for the system of equations
void Initalize(int dimension)
{
_dimension=dimension;
_Ap.resize(_dimension+1);
_M.clear();
_B.resize(_dimension);
_X.resize(_dimension);
}
double &A(int row,int col)
{
IndexType I=IndexType(row,col);
mapType::const_iterator ci=_M.find(I);
if (ci==_M.end())
{
std::swap<int>(I.first,I.second);
ci=_M.find(I);
}
assert(ci!=_M.end());
int index=(*ci).second;
return(_Ax[index]);
}
double &B(int i)
{return(_B[i]);}
double &X(int i)
{return (_X[i]);}
void Solve()
{
int d,i;
// /* factorize A into LDL' (P and Pinv not used) */
ldl_symbolic (_dimension, &(*_Ap.begin()), &(*_Ai.begin()), &(*Lp.begin()),
&(*Parent.begin()), &(*Lnz.begin()), &(*Flag.begin()), NULL, NULL) ;
// printf ("Nonzeros in L, excluding diagonal: %d\n", Lp [_dimension]) ;
d = ldl_numeric (_dimension, &(*_Ap.begin()), &(*_Ai.begin()), &(*_Ax.begin()), &(*Lp.begin())
, &(*Parent.begin()), &(*Lnz.begin()), &(*Li.begin()), &(*Lx.begin()),
&(*D.begin()), &(*Y.begin()), &(*Pattern.begin()),
&(*Flag.begin()), NULL, NULL) ;
if (d == _dimension)
{
/* solve Ax=b, overwriting b with the solution x */
ldl_lsolve (_dimension, &(*_B.begin()), &(*Lp.begin()), &(*Li.begin()), &(*Lx.begin())) ;
ldl_dsolve (_dimension, &(*_B.begin()), (&*D.begin()) );
ldl_ltsolve (_dimension, &(*_B.begin()), &(*Lp.begin()), &(*Li.begin()), &(*Lx.begin())) ;
for (i = 0 ; i < _dimension ; i++)
_X[i]=_B[i];//printf ("x [%d] = %g\n", i, b [i]) ;
}
else///dl_numeric failed
{
assert(0);
}
}
bool IsSymmetric()
{return true;}
void Zero()
{
for (int i=0;i<Size();i++)
_Ax[i]=0;
}
int Size(){return (_dimension);}
///K is symmetric positice definite matrix
void CreateSparse(std::vector<IndexType> Entries)
{
_Ax.clear();
_Ai.clear();
int _nonzero=0;
///put the index of vertices for each edge
///in the right order for simmetry of the sistem
std::vector<IndexType>::iterator Vi;
for (Vi=Entries.begin();Vi<Entries.end();Vi++)
{
assert((*Vi).first>=0);
assert((*Vi).second>=0);
if ((*Vi).first>(*Vi).second)
std::swap<int>((*Vi).first,(*Vi).second);
}
///the sort and erase duplicates
std::sort(Entries.begin(),Entries.end());
std::vector<IndexType>::iterator Vend=std::unique(Entries.begin(),Entries.end());
Entries.erase(Vend,Entries.end());
_Ax.resize(Entries.size());
_Ai.resize(Entries.size());
_M.clear();
int col=0;
int i=0;
Vi=Entries.begin();
while (Vi<Entries.end())
{
col=(*Vi).first;
_Ap[i]=_nonzero;
//go to next colummn
while ((col==(*Vi).first)&&(Vi<Entries.end()))
{
IndexType I=IndexType((*Vi).first,(*Vi).second);
_M.insert(std::pair<IndexType,int>(I,_nonzero));
_Ai[_nonzero]=(*Vi).second;
_nonzero++;
Vi++;
}
i++;
}
_Ap[_dimension]=_nonzero;
Lx.resize(_nonzero);
D.resize(_dimension);
Y.resize(_dimension);
Li.resize(_nonzero);
Lp.resize(_dimension+1);
Parent.resize(_dimension);
Lnz.resize(_dimension);
Flag.resize(_dimension);
Pattern.resize(_dimension);
}
};
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