Eigen command VS DOFs

[hnsmengyu]

Now, there is a 2D 3 storys frame with 4 bays, each node have a horzontal mass and a very small mass along the vertical, the rotation mass is zero. If the eigen command is used to get the eigen values, only the first 22 DOFs can be calculated, that is to say(according to the mannual), the frame have 23 DOFs.
So, I wander how does the DOFs are computed(23 DOFs)!

[vesna]

you can get all 23 values if you use -fullGenLapack solver for the eigen analysis.

e.g.,
eigen -fullGenLapack 23

[hnsmengyu]

vesna wrote:
> you can get all 23 values if you use -fullGenLapack solver for the eigen
> analysis.
>
> e.g.,
> eigen -fullGenLapack 23
Sorry, acturally I want to know how to get the numbers of DOFs of the frame, say, the 2D frame have 15 nodes, considering the rotation mass is zero, there will be 15*2=30 DOFs. But according to the eigen analysis, only the first 22 eigens can be computed, or the frame only have TWENTY-THREE DOFs, I dont know why!

[vesna]

If you type this:

eigen -fullGenLapack 30

you should get all 30 eigenvalues.

Look at the command manual:
http://opensees.berkeley.edu/wiki/index ... en_Command