hi,
I have 3 vertical eigen matrices and I would like to concatenate them, like in matlab C=[B1;B2; B3 ];
i want concatenate them In this case, C(B1.cols()+B2.cols()+B3.cols(),1)
MatrixXd B1,B2,B3,B4;
C<<B1,B2,B3;

Is there anything equivalent in eigen?
Thanks.

I am not sure exactly what the question is. It seems that the command C<<B1,B2,B3 that you mention is precisely what you want: it can be used to concatenate matrices vertically and horizontally. See our documentation page at http://eigen.tuxfamily.org/dox/group__T ... ation.html for some more details.