Using GDB with Eigen C++ library

Question

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.

score 26 · Answer 1 · answered Feb 20 '15 at 08:25

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.

score 25 · Accepted Answer · edited Oct 01 '20 at 07:43

25

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.

edited Oct 01 '20 at 07:43

Vikas

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answered Aug 01 '14 at 20:32

ggael

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Is there something similar for lldb on mac os x? – Alec Jacobson Nov 21 '16 at 17:51
I'm not aware of lldb script yet, but it should be difficult to adapt the gdb one to lldb. – ggael Nov 23 '16 at 09:26
link in the answer is dead – chutsu Jan 09 '18 at 18:05
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Can you explain how to install this python file? – user650261 May 25 '18 at 16:22
It's explained in the file itself! – ggael May 26 '18 at 21:02
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I have installed it but it's unclear to me how to use it. Could you provide any info on that? I'm using the eclipse debugger btw – C. Binair Aug 25 '21 at 07:23

score 0 · Answer 3 · answered Jun 11 '22 at 20:02

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There is a github project specifically for adding eigen printing support to GDB.

It appears to be based on the code linked in this answer.

answered Jun 11 '22 at 20:02

nobane

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Using GDB with Eigen C++ library

3 Answers3

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