bool ON_Matrix::Multiply( const ON_Matrix& a, const ON_Matrix& b )
{
int i, j, k, mult_count;
double x;
if (a.ColCount() != b.RowCount() )
return false;
if ( a.RowCount() < 1 || a.ColCount() < 1 || b.ColCount() < 1 )
return false;
if ( this == &a ) {
ON_Matrix tmp(a);
return Multiply(tmp,b);
}
if ( this == &b ) {
ON_Matrix tmp(b);
return Multiply(a,tmp);
}
Create( a.RowCount(), b.ColCount() );
mult_count = a.ColCount();
double const*const* am = a.ThisM();
double const*const* bm = b.ThisM();
double** this_m = ThisM();
for ( i = 0; i < m_row_count; i++ ) for ( j = 0; j < m_col_count; j++ ) {
x = 0.0;
for (k = 0; k < mult_count; k++ ) {
x += am[i][k] * bm[k][j];
}
this_m[i][j] = x;
}
return true;
}
bool ON_Matrix::Add( const ON_Matrix& a, const ON_Matrix& b )
{
int i, j;
if (a.ColCount() != b.ColCount() )
return false;
if (a.RowCount() != b.RowCount() )
return false;
if ( a.RowCount() < 1 || a.ColCount() < 1 )
return false;
if ( this != &a && this != &b ) {
Create( a.RowCount(), b.ColCount() );
}
double const*const* am = a.ThisM();
double const*const* bm = b.ThisM();
double** this_m = ThisM();
for ( i = 0; i < m_row_count; i++ ) for ( j = 0; j < m_col_count; j++ ) {
this_m[i][j] = am[i][j] + bm[i][j];
}
return true;
}