Hi everyone!

A few days ago I met a problem that seemed a bit strange.
Pseudo codes:

MatrixXd A = MatrixXd::Random(10, 10); // A matrix of size 10 x 10
auto blk = A.leftCols(2); // Now blk 'points' to the submatrix that contains the first two cols of A
// here are some other works
....
blk = A.leftCols(3); // ERROR! We know this line actually assigns the first three cols to the first two and hence runtime_error occurs.

But in some rare cases I actually intend to 'rebind' blk to the first three cols rather than perform the assignments.
Is there any method that can make blk 'points' to the first three cols of A and avoids change the the type of blk to MatrixXd?