Eigen Analysis not solved

[NALLAGATLABHAGYASREE]

Hi
I am doing eigen analysis on building with bearings, for bearings i am using ElastomericBearingBoucWen element
when i did eigen analysis i am getting the error as below

ArpackSolver::Error with _saupd info = -9999
Could not build an Arnoldi factorization.IPARAM(5) the size of the current Arnoldi factorization: is 1factorization. The user is advised to check thatenough workspace and array storage has been allocated.
WARNING DirectIntegrationAnalysis::eigen() - EigenSOE failed in solve()

What does this error means, I checked connectivity of my nodes every node is connected and model is constrained properly.

[Ulbong]

I'm trying to do Eigen analysis. but I got same problem as you.
I don't know how to solve this. If you solved it, can you give me some advises?

these are my scripts
1. Model
------------------------------------------------------------------------
#input
set m 5.0

#material
set A 100.0
set I 100.0
set E 10000.0

#geometry
set L 20.0

#define the model
model BasicBuilder -ndm 2 -ndf 3

# nodal coordinates
node 1 0.0 0.0 ;
node 2 0.0 $L ;

#single point constraints -- Boundary Conditions
fix 1 1 1 1 ;

#assign mass
mass 2 $m $m 0;

#define geometric transformation
set TransfTag 1;
geomTransf Linear $TransfTag ;

#define elements
element elasticBeamColumn 1 1 2 $A $E $I $TransfTag;
----------------------------------------------------------------------------------

2. Eigenvalue Analysis
--------------------------------------------------------------------------------
#LOAD MODEL
source Model2.tcl

#input
set numModes 2
file mkdir MODE;

#record eigenvectors
for { set k 1 } { $k <= $numModes } { incr k } {
recorder Node -file [format "modes/mode%i.out" $k] -nodeRange 1 2 -dof 1 2 3 "eigen $k"
}

#perform eigen analysis
set lambda [eigen $numModes];

# calculate frequencies and periods of the structure
set omega {}
set f {}
set T {}
set pi 3.141593

foreach lam $lambda {
lappend omega [expr sqrt($lam)]
lappend f [expr sqrt($lam)/(2*$pi)]
lappend T [expr (2*$pi)/sqrt($lam)]
}

puts "periods are $T"

#write the output file cosisting of periods
set period "MODE/Periods.txt"
set Periods [open $period "w"]
foreach t $T {
puts $Periods " $t"
}
close $Periods

# Run a one step gravity load with no loading (to record eigenvectors)
#-----------------------------------------------------------------------
integrator LoadControl 0 1 0 0

# Convergence test
# tolerance maxIter displayCode
test EnergyIncr 1.0e-10 100 0

# Solution algorithm
algorithm Newton

# DOF numberer
numberer RCM

# Constraint handler
constraints Transformation


# System of equations solver
system ProfileSPD

analysis Static
set res [analyze 1]
if {$res < 0} {
puts "Modal analysis failed"
}
------------------------------------------------------------------------------------
Plz help us...

[Ulbong]

Hey I just solved it.
For my one, I incorrectly set number of modes (2). because my model is just single dof column model.
I modified [set numModes 2] -> [set numModes 1] and it worked!

[NALLAGATLABHAGYASREE]

In my model this won't be a problem as mine is not a single DOF, I changed some material properties and the error disappeared.

[Ulbong]

Ok Thanks!

[selimgunay]

The eigen command computes the eigenvalues and eigenvectors for at most ndof-1 modes, where ndof is the number of degrees of freedom with mass.

[ankurjain]

the default solver type is genBandArpack which can only find (N-1) modes, where N is the no of degree of freedom. So better change the solver type to fullGenLaPack ....

Best of luck