I am using the Eigen C++ library downloadable from http://eigen.tuxfamily.org/. This is a C++ library for easier handling of Matrices and Arrays. I use g++ compiler and gdb for debugging. However, I found that I am unable to print the content of a Matrix (provided by Eigen) while using gdb.
ggael
You have to install a gdb extension that you can find in eigen/debug/gdb/.
The comment at the beginning of the file explains how to install it.
One trick you can use is the .data() member, it gives you a pointer to the raw array that contains the data. With that you can print it in GDB like so:
print *X.data()@Length_X
where X is the eigen variable and Length_X is the product of its rows and columns.
来源：https://stackoverflow.com/questions/25085465/using-gdb-with-eigen-c-library