//---------------------------------------------------------
bool CSG_Matrix::Add_Row(double *Data)
{
if( Add_Rows(1) )
{
Set_Row(m_ny - 1, Data);
return( true );
}
return( false );
}
/**
* Sets the number of rows to nRows. Values will be preserved.
* Returns true if successful.
*/
bool CSG_Vector::Set_Rows(int nRows)
{
if( nRows > Get_N() )
{
return( Add_Rows(nRows - Get_N()) );
}
if( nRows < Get_N() )
{
return( Del_Rows(Get_N() - nRows) );
}
return( true );
}
//---------------------------------------------------------
bool CSG_Matrix::Set_Rows(int nRows)
{
if( nRows > m_ny )
{
return( Add_Rows(nRows - m_ny) );
}
if( nRows < m_ny )
{
return( Del_Rows(m_ny - nRows) );
}
return( true );
}
// perform Guass-Jordanian elimination: The matrix will become
// it's inverse
void XSQUARE_MATRIX::Inverse_GJ(void)
{
if (m_lpdValues)
{
XSQUARE_MATRIX cI(m_uiN);
cI.Identity();
// allocate work space
double dScalar;
// Using row reduction, reduce the source matrix to the identity,
// and the identity will become A^{-1}
for (unsigned int uiRow = 0; uiRow < m_uiN; uiRow++)
{
if (m_lpdValues[uiRow * m_uiN + uiRow] == 0.0)
{
for (unsigned int uiRowInner = uiRow + 1;
uiRowInner < m_uiN;
uiRowInner++)
{
if (m_lpdValues[uiRowInner * m_uiN + uiRow] != 0.0)
{
Swap_Rows(uiRow,uiRowInner);
cI.Swap_Rows(uiRow,uiRowInner);
}
}
}
dScalar = 1.0 / m_lpdValues[uiRow * m_uiN + uiRow];
Scale_Row(uiRow,dScalar);
cI.Scale_Row(uiRow,dScalar);
for (unsigned int uiRowInner = 0;
uiRowInner < m_uiN;
uiRowInner++)
{
double dRow_Scalar =
-m_lpdValues[uiRowInner * m_uiN + uiRow];
if (uiRowInner != uiRow)
{
cI.Add_Rows(uiRowInner,uiRow,dRow_Scalar,false);
Add_Rows(uiRowInner,uiRow,dRow_Scalar,true);
}
}
}
// copy result into current matrix
*this = cI;
}
}
