这样的事情怎么样?
class compressed_matrix_nonzero_default : public boost::numeric::ublas::compressed_matrix<double>
{
double def;
public:
compressed_matrix_nonzero_default( int s1, int s2 )
: boost::numeric::ublas::compressed_matrix<double>(s1,s2)
, def(0)
{
}
void setDefault( double d ) { def = d; }
double value( int i, int j )
{
typedef boost::numeric::ublas::compressed_matrix<double>::iterator1 it1_t;
typedef boost::numeric::ublas::compressed_matrix<double>::iterator2 it2_t;
for (it1_t it1 = begin1(); it1 != end1(); it1++)
{
if( it1.index1() < i )
continue;
if( it1.index1() > i ) {
return def;
}
for (it2_t it2 = it1.begin(); it2 != it1.end(); it2++)
{
if( it2.index2() < j )
continue;
if( it2.index2() == j )
return *it2;
if( it2.index2() > j )
return def;
}
}
return def;
}
};
用法
compressed_matrix_nonzero_default MNZ(3,3);
MNZ.setDefault(-100);
MNZ (1,1) = 45;
for( int i = 0; i < 3; i++ ) {
for( int j = 0; j < 3; j++ ) {
std::cout << MNZ.value(i,j) << ",";
}
std::cout << "\n";
}