I want to compare two or more Eigen rows of a matrix, so as to know if they’re equal. Of course this is easy with a loop, but I’d like a more performant solution, without a loop.

MatrixXi M(12,3) is:

===========================================
M (Rows: 12 Cols: 3)
===========================================
[[1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]
 [1, 1, 1]]
===========================================

Is this possible? Thank you