.. _testmodels-loaduserfunctiontest:

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loadUserFunctionTest.py
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You can view and download this file on Github: `loadUserFunctionTest.py <https://github.com/jgerstmayr/EXUDYN/tree/master/main/pythonDev/TestModels/loadUserFunctionTest.py>`_

.. code-block:: python
   :linenos:

   #+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   # This is an EXUDYN example
   #
   # Details:  Test sensor with user function; 
   #           This test includes two cases:
   #           1) symbolic user function which allows to use regular graphics multithreading and is faster
   #           2) Python user function, which is convenient to be used, but requires to set useMultiThreadedRendering=False in visualizationSettings.general
   #
   # Author:   Johannes Gerstmayr
   # Date:     2021-02-18
   #
   # 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 exudyn as exu
   from exudyn.itemInterface import *
   from exudyn.basicUtilities import NormL2
   from exudyn.utilities import CreateSymbolicUserFunction
   from math import pi
   
   useGraphics = True #without test
   #+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   #you can erase the following lines and all exudynTestGlobals related operations if this is not intended to be used as TestModel:
   try: #only if called from test suite
       from modelUnitTests import exudynTestGlobals #for globally storing test results
       useGraphics = exudynTestGlobals.useGraphics
   except:
       class ExudynTestGlobals:
           pass
       exudynTestGlobals = ExudynTestGlobals()
   #+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   #useGraphics = False
   
   esym = exu.symbolic
   import numpy as np
   
   result = 0
   cases = ['PythonUserFunction', 'SymbolicUserFunction']
   for case in cases:
       exu.Print('CASE: '+case)
       SC = exu.SystemContainer()
       mbs = SC.AddSystem()
       
       useSymbolicUF = case == 'SymbolicUserFunction'
       
       #variable can be used to switch behavior
       #esym.variables.Set('flag',1)
       
       if useSymbolicUF:
           #scaling load with time
           def UFload(mbs, t, loadVector):
               return esym.cos(2*(2*pi)*t) * loadVector
       else:
           #general load changing over time (rotating)
           def UFload(mbs, t, loadVector):
               return [np.sin(2*(2*pi)*t) * loadVector[0], 
                       np.cos(2*(2*pi)*t) * loadVector[0], 
                       0]
       
       oGround = mbs.CreateGround()
       
       oMassPoint = mbs.CreateMassPoint(referencePosition=[1.+0.05,0,0], physicsMass=1, drawSize=0.1)
       co = mbs.CreateSpringDamper(bodyNumbers=[oGround, oMassPoint],
                                   referenceLength = 1, stiffness = 100, damping = 1)
       sMass = mbs.AddSensor(SensorBody(bodyNumber=oMassPoint, 
                                        outputVariableType=exu.OutputVariableType.Position))
       
       load = mbs.CreateForce(bodyNumber=oMassPoint, loadVector=[10,0,0], 
                              loadVectorUserFunction=UFload)
       
       if useSymbolicUF:
           #these steps have to be done to inject the symbolic user function into exudyn as C-function
           symFuncLoad = CreateSymbolicUserFunction(mbs, UFload, 'loadVectorUserFunction', load)
           mbs.SetLoadParameter(load, 'loadVectorUserFunction', symFuncLoad)
       
           #check function:
           exu.Print('load user function:  ',symFuncLoad)
       
       
       #assemble and solve system for default parameters
       mbs.Assemble()
       
       endTime = 10
       stepSize = 0.005
       
       SC.visualizationSettings.loads.drawSimplified = False
       SC.visualizationSettings.loads.drawWithUserFunction = True
       SC.visualizationSettings.loads.fixedLoadSize = False #otherwise only sign will be shown
       SC.visualizationSettings.loads.loadSizeFactor = 0.025
       SC.visualizationSettings.general.useMultiThreadedRendering = useSymbolicUF
       SC.visualizationSettings.nodes.drawNodesAsPoint = False
       SC.visualizationSettings.nodes.tiling = 32
       SC.visualizationSettings.general.graphicsUpdateInterval = 0.02
       SC.visualizationSettings.general.renderWindowString = 'Test case: '+case
       
       simulationSettings = exu.SimulationSettings()
       #simulationSettings.solutionSettings.solutionWritePeriod = 0.01
       simulationSettings.solutionSettings.writeSolutionToFile = False
       simulationSettings.timeIntegration.verboseMode = 1
       simulationSettings.timeIntegration.simulateInRealtime = useGraphics #for visualization to be viewed by user!
       
       simulationSettings.timeIntegration.numberOfSteps = int(endTime/stepSize)
       simulationSettings.timeIntegration.endTime = endTime
       simulationSettings.timeIntegration.newton.useModifiedNewton = True
       
       if useGraphics:
           exu.StartRenderer()
           mbs.WaitForUserToContinue()
       
       mbs.SolveDynamic(simulationSettings, solverType=exu.DynamicSolverType.RK44)
       
       if useGraphics:
           exu.StopRenderer() #safely close rendering window!
       
       result += NormL2(mbs.GetSensorValues(sMass))
   
   
   
   #evaluate final (=current) output values
   exu.Print('result of loadUserFunctionTest=',result)
   
   exudynTestGlobals.testResult = result  #1.8051173706570725