//! compute this = this - B
bool DenseMatrix::Subtract( const DenseMatrix & B )
{
if ( Rows() != B.Rows() || Columns() != B.Columns() )
return false; // matrices are incompatible
for ( unsigned int r = 0; r < m_nRows; ++r ) {
for ( unsigned int c = 0; c < m_nCols; ++c ) {
M(r,c) -= M_B(c,r);
}
}
return true;
}
//! compute C = this*B;
bool DenseMatrix::Multiply(const DenseMatrix & B, DenseMatrix & C) const
{
unsigned int nRowsA = Rows();
unsigned int nColsA = Columns();
unsigned int nRowsB = B.Rows();
unsigned int nColsB = B.Columns();
if ( nColsA != nRowsB )
return false; // matrices are incompatible
C.Resize(nRowsA,nColsB);
for ( unsigned int ra = 0; ra < nRowsA; ++ra ) {
for ( unsigned int cb = 0; cb < nColsB; ++cb ) {
double rcsum = 0;
for ( unsigned int ca = 0; ca < nColsA; ++ca )
rcsum += M(ra,ca) * M_B(ca,cb);
M_C(ra,cb) = rcsum;
}
}
return true;
}