Hi-

I want to extract my matrix and store it in my Desktop. I use Eigen::saveMarket(mat, "abc.mtx"), but I couldn't find this file in my laptop.

Anybody knows where was this file stored???

It is stored in the "working directory" of your executable, so most likely in the same directory than your executable.

Are there any other methods in Eigen to save matrix as HB format???

nope.