Eigen - complex
Moderators: silvia, selimgunay, Moderators
Eigen - complex
Hi,
when I issue the command eigen -fullGenLapack 5, I get the following warning :
- the eigenvalue 37 is complexe with magnitude 1
- the eigenvalue 38 is complexe with magnitude 1
I wonder why do I get this warning since I only asked for the first 5 values?
when I issue the command eigen -fullGenLapack 5, I get the following warning :
- the eigenvalue 37 is complexe with magnitude 1
- the eigenvalue 38 is complexe with magnitude 1
I wonder why do I get this warning since I only asked for the first 5 values?
Re: Eigen - complex
need to see the script.
Re: Eigen - complex
The code is too long to post here. I however have funny result with this little code here :
wipe
model BasicBuilder -ndm 2 -ndf 2
node 1 0. 0.
node 2 1. 0.
node 3 1. 1.
node 4 0. 1.
fix 1 1 1
fix 2 1 1
set mDen 2000.
set WY [expr $mDen*9.81*-1]
set thick 1.0
set type PlaneStrain
nDMaterial ElasticIsotropic 0 100e3 0.3 2000.
element SSPquad 1 4 3 2 1 0 $type $thick 0. $WY
system FullGeneral
test NormDispIncr 1.e-5 20 1
constraints Transformation
integrator LoadControl 1 1 1 1
algorithm KrylovNewton
numberer RCM
analysis Static
analyze 1
Try the following :
eigen 1
Then :
eigen 2
Then :
eigen 3
Now compare with
eigen fullGenLapack 3
eigen fullGenLapack 2
why is this happening? In my larger model, when I issue eigen fullGenLapack it nevers print anythin and I have to kill the program. I am afraid of using eigen command because results looks wrong.
wipe
model BasicBuilder -ndm 2 -ndf 2
node 1 0. 0.
node 2 1. 0.
node 3 1. 1.
node 4 0. 1.
fix 1 1 1
fix 2 1 1
set mDen 2000.
set WY [expr $mDen*9.81*-1]
set thick 1.0
set type PlaneStrain
nDMaterial ElasticIsotropic 0 100e3 0.3 2000.
element SSPquad 1 4 3 2 1 0 $type $thick 0. $WY
system FullGeneral
test NormDispIncr 1.e-5 20 1
constraints Transformation
integrator LoadControl 1 1 1 1
algorithm KrylovNewton
numberer RCM
analysis Static
analyze 1
Try the following :
eigen 1
Then :
eigen 2
Then :
eigen 3
Now compare with
eigen fullGenLapack 3
eigen fullGenLapack 2
why is this happening? In my larger model, when I issue eigen fullGenLapack it nevers print anythin and I have to kill the program. I am afraid of using eigen command because results looks wrong.
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- Posts: 913
- Joined: Mon Sep 09, 2013 8:50 pm
- Location: University of California, Berkeley
Re: Eigen - complex
eigen command generally works properly.
To explore the source of the problem, could you change the material to uniaxial elastic and assign masses to the nodes.
To explore the source of the problem, could you change the material to uniaxial elastic and assign masses to the nodes.