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(testmodels-compareabaqusansysrotoreigenfrequencies)=
# compareAbaqusAnsysRotorEigenfrequencies.py

You can view and download this file on Github: [compareAbaqusAnsysRotorEigenfrequencies.py](https://github.com/jgerstmayr/EXUDYN/tree/master/python/TestModels/compareAbaqusAnsysRotorEigenfrequencies.py)

```{code-block} python
:linenos:

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# This is an EXUDYN example
#
# Details:  Example to compute eigenfrequencies of a rotor
#           NOTE that this example requires files from a subdirectory testData as provided on github
#
# Author:   Stefan Holzinver, Johannes Gerstmayr
# Date:     2020-05-18
#
# Copyright:This file is part of Exudyn. Exudyn is free software. You can redistribute it and/or modify it under the terms of the Exudyn license. See 'LICENSE.txt' for more details.
#
#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

import numpy as np
from scipy.sparse import linalg
import scipy as sp

import exudyn as exu
from exudyn.utilities import * #includes itemInterface and rigidBodyUtilities
import exudyn.graphics as graphics
from exudyn.FEM import *

testIsActive = exu.sys.get('testIsActive', False)

numberOfModes = 18
useSparseSolverRoutine = False

errorResult = 0

testDataDir = "testData/"
#if not testIsActive:
#    testDataDir = "testData/"

###############################################################################
# Ansys - lumped mass matrix formulation - Sparse Matrix - MMF format
###############################################################################

#read finite element model
exu.sys['testResult'] = 0
for testNumber in range(2):
    if testNumber == 1:
        useSparseSolverRoutine = True
    
    fem = FEMinterface()
    #exu.Print("read matrices ...")
    fem.ReadMassMatrixFromAnsys(fileName=testDataDir + 'rotorAnsysMassMatrixSparse.txt', 
                                dofMappingVectorFile=testDataDir + 'rotorAnsysMatrixDofMappingVector.txt')
    fem.ReadStiffnessMatrixFromAnsys(fileName=testDataDir + 'rotorAnsysStiffnessMatrixSparse.txt',
                                dofMappingVectorFile=testDataDir + 'rotorAnsysMatrixDofMappingVector.txt')
    
    #exu.Print("compute eigenmodes ...")
    fem.ComputeEigenmodes(numberOfModes, useSparseSolver = useSparseSolverRoutine)
    
    if not testIsActive:
        exu.Print('natural frequencies from Ansys model (Lumped Mass Matrix, MMF-Format)', fem.GetEigenFrequenciesHz()[0:numberOfModes])
    
    if not useSparseSolverRoutine:
        f6 = fem.GetEigenFrequenciesHz()[6] - 104.63701055079783 #reference solution
    else:
        #compare with dense matrix solution; 
        #due to random initialization, the results change with every computation ==> approx. 1e-11 repeatability
        f6 = fem.GetEigenFrequenciesHz()[6] - 104.6370105507865 
    f6*=1e-6 #use offset also for abaqus, as it gives non-reproducible results in dense case (32/64bit?)
    exu.Print('natural frequencies from Ansys model, sparse=',str(useSparseSolverRoutine),":", fem.GetEigenFrequenciesHz()[6] )
    errorResult += f6

    exu.sys['testResult'] += 1e-6*fem.GetEigenFrequenciesHz()[6]

    ###############################################################################
    # Abaqus
    ###############################################################################
    
    #read finite element model
    fem = FEMinterface()
    #exu.Print("read matrices ...")
    fem.ReadMassMatrixFromAbaqus(fileName=testDataDir + 'rotorDiscTestMASS1.mtx')
    fem.ReadStiffnessMatrixFromAbaqus(fileName=testDataDir + 'rotorDiscTestSTIF1.mtx')
    fem.ScaleStiffnessMatrix(1e-2) #in Ansys, the stiffness matrix is already scaled!
        
    #exu.Print("compute eigenmodes ...")
    fem.ComputeEigenmodes(numberOfModes, useSparseSolver = useSparseSolverRoutine)

    if not testIsActive:
        exu.Print('natural frequencies from Abaqus model (Lumped Mass Matrix)',fem.GetEigenFrequenciesHz()[0:numberOfModes])
    
    if not useSparseSolverRoutine:
        f6 = fem.GetEigenFrequenciesHz()[6] - 104.6370132606291 #reference solution
    else:
        #compare with dense matrix solution; 
        #due to random initialization, the results change with every computation ==> approx. 1e-11 repeatability
        f6 = fem.GetEigenFrequenciesHz()[6] - 104.6370132606291 
    f6*=1e-6 #use offset also for abaqus, as it gives non-reproducible results in dense case (32/64bit?)
    exu.Print('natural frequencies from Abaqus model, sparse=',str(useSparseSolverRoutine),":", fem.GetEigenFrequenciesHz()[6] )
    errorResult += f6
    exu.sys['testResult'] += 1e-6*fem.GetEigenFrequenciesHz()[6]

exu.Print('error of compareAbaqusAnsysRotorEigenfrequencies (due to sparse solver)=',errorResult)
if abs(errorResult) < 1e-15: #usually of size 1e-17
    errorResult = 0 #due to randomized sparse solver results, take this treshold!
    
exu.Print('solution of compareAbaqusAnsysRotorEigenfrequencies (with treshold)=',errorResult)
#exu.sys['testResult'] computed above
```