New Post: syntax for armadillo into Math.net

Hi,
I am a new to Math.Net Numerics and am struck in using the following in Math.NEt

from armadillo c++ program
rowvec td;
colvec dda = (td.st() - td(0)) * 5;
dda = dda .rows(1, 4- 1);


Using Math.Net in c#
Matrix<double> td;
Matrix<double> dda = (td.Transpose() - td[0,0] * 5);
dda = dda .rows(1, 4- 1); //this line I am not able to convert may be like dda = dda[1,3] doesn't work as it returns a double

What is the best way to convert ...
Thanks,
Codeplus_vl