Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow.conf.json
loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo", uses=false)
loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo", uses=false)
loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo", uses=false)
loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 1.6.0+build.1/package.mo", uses=false)
Using package Buildings with version 1.6 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 1.6.0+build.1/package.mo)
Using package Modelica with version 3.2.3 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo)
Using package Complex with version 4.0.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo)
Using package ModelicaServices with version 4.0.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo)
Running command: translateModel(Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow")
translateModel(Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow")
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.0008238/0.0008237, allocations: 98.03 kB / 15.36 MB, free: 0.7344 MB / 14.72 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.006369/0.00637, allocations: 170.7 kB / 16.27 MB, free: 6.652 MB / 14.72 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo): time 1.738/1.738, allocations: 205.4 MB / 222.4 MB, free: 5.555 MB / 174.1 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 1.6.0+build.1/package.mo): time 0.6364/0.6364, allocations: 95.62 MB / 366.4 MB, free: 10.25 MB / 302.1 MB
Notification: Modelica requested package Complex of version 3.2.3. Complex 4.0.0 is used instead which states that it is fully compatible without conversion script needed.
Notification: Modelica requested package ModelicaServices of version 3.2.3. ModelicaServices 4.0.0 is used instead which states that it is fully compatible without conversion script needed.
Notification: Buildings requested package Modelica of version 3.2.1. Modelica 3.2.3 is used instead which states that it is fully compatible without conversion script needed.
Notification: Performance of FrontEnd - loaded program: time 0.0005835/0.0005834, allocations: 20 kB / 447.5 MB, free: 8.969 MB / 382.1 MB
Notification: Performance of FrontEnd - Absyn->SCode: time 0.4285/0.4291, allocations: 70.32 MB / 0.5057 GB, free: 16.35 MB / 382.1 MB
Notification: Performance of NFInst.instantiate(Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow): time 0.6355/1.065, allocations: 160.6 MB / 0.6625 GB, free: 420 kB / 494.1 MB
Notification: Performance of NFInst.instExpressions: time 0.01926/1.084, allocations: 9.896 MB / 0.6722 GB, free: 152 kB / 494.1 MB
Notification: Performance of NFInst.updateImplicitVariability: time 0.004266/1.088, allocations: 52.97 kB / 0.6722 GB, free: 148 kB / 494.1 MB
Notification: Performance of NFTyping.typeComponents: time 0.002671/1.091, allocations: 488.9 kB / 0.6727 GB, free: 132 kB / 494.1 MB
Notification: Performance of NFTyping.typeBindings: time 0.006568/1.098, allocations: 1.071 MB / 0.6737 GB, free: 72 kB / 494.1 MB
Notification: Performance of NFTyping.typeClassSections: time 0.01274/1.11, allocations: 2.298 MB / 0.676 GB, free: 15.98 MB / 0.4981 GB
Notification: Performance of NFFlatten.flatten: time 0.008275/1.119, allocations: 3.391 MB / 0.6793 GB, free: 15.98 MB / 0.4981 GB
Notification: Performance of NFFlatten.resolveConnections: time 0.003019/1.122, allocations: 0.9392 MB / 0.6802 GB, free: 15.84 MB / 0.4981 GB
Notification: Performance of NFEvalConstants.evaluate: time 0.003471/1.125, allocations: 0.8548 MB / 0.681 GB, free: 15.84 MB / 0.4981 GB
Notification: Performance of NFSimplifyModel.simplify: time 0.003361/1.129, allocations: 0.9774 MB / 0.682 GB, free: 15.83 MB / 0.4981 GB
Notification: Performance of NFPackage.collectConstants: time 0.0009152/1.13, allocations: 63.47 kB / 0.6821 GB, free: 15.83 MB / 0.4981 GB
Notification: Performance of NFFlatten.collectFunctions: time 0.005291/1.135, allocations: 0.9643 MB / 0.683 GB, free: 15.81 MB / 0.4981 GB
Notification: Performance of NFScalarize.scalarize: time 0.001317/1.136, allocations: 331.5 kB / 0.6833 GB, free: 15.81 MB / 0.4981 GB
Notification: Performance of NFVerifyModel.verify: time 0.003062/1.139, allocations: 0.7019 MB / 0.684 GB, free: 15.78 MB / 0.4981 GB
Notification: Performance of NFConvertDAE.convert: time 0.007473/1.147, allocations: 2.433 MB / 0.6864 GB, free: 14.71 MB / 0.4981 GB
Notification: Performance of FrontEnd - DAE generated: time 1.285e-05/1.147, allocations: 0.625 kB / 0.6864 GB, free: 14.71 MB / 0.4981 GB
Notification: Performance of FrontEnd: time 1.733e-06/1.147, allocations: 3.938 kB / 0.6864 GB, free: 14.7 MB / 0.4981 GB
Notification: Performance of Transformations before backend: time 0.0001054/1.147, allocations: 0 / 0.6864 GB, free: 14.7 MB / 0.4981 GB
Notification: Model statistics after passing the front-end and creating the data structures used by the back-end:
 * Number of equations: 159
 * Number of variables: 159
Notification: Performance of Generate backend data structure: time 0.008281/1.155, allocations: 1.762 MB / 0.6881 GB, free: 13.54 MB / 0.4981 GB
Notification: Performance of prepare preOptimizeDAE: time 6.224e-05/1.155, allocations: 12.61 kB / 0.6881 GB, free: 13.54 MB / 0.4981 GB
Notification: Performance of preOpt normalInlineFunction (simulation): time 0.00142/1.157, allocations: 163.9 kB / 0.6883 GB, free: 13.46 MB / 0.4981 GB
Notification: Performance of preOpt evaluateParameters (simulation): time 0.004081/1.161, allocations: 1.111 MB / 0.6894 GB, free: 12.9 MB / 0.4981 GB
Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0004374/1.161, allocations: 73.34 kB / 0.6894 GB, free: 12.88 MB / 0.4981 GB
Notification: Performance of preOpt expandDerOperator (simulation): time 0.0004222/1.162, allocations: 74.25 kB / 0.6895 GB, free: 12.85 MB / 0.4981 GB
Notification: Performance of preOpt clockPartitioning (simulation): time 0.004083/1.166, allocations: 0.9803 MB / 0.6905 GB, free: 12.2 MB / 0.4981 GB
Notification: Performance of preOpt findStateOrder (simulation): time 3.321e-05/1.166, allocations: 4 kB / 0.6905 GB, free: 12.2 MB / 0.4981 GB
Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0002225/1.166, allocations: 32.22 kB / 0.6905 GB, free: 12.18 MB / 0.4981 GB
Notification: Performance of preOpt inlineArrayEqn (simulation): time 2.704e-05/1.166, allocations: 22.8 kB / 0.6905 GB, free: 12.17 MB / 0.4981 GB
Notification: Performance of preOpt removeEqualRHS (simulation): time 0.002694/1.169, allocations: 0.8282 MB / 0.6913 GB, free: 11.79 MB / 0.4981 GB
Warning: The model contains alias variables with redundant start and/or conflicting nominal values. It is recommended to resolve the conflicts, because otherwise the system could be hard to solve. To print the conflicting alias sets and the chosen candidates please use -d=aliasConflicts.
Notification: Performance of preOpt removeSimpleEquations (simulation): time 0.007761/1.177, allocations: 4.089 MB / 0.6953 GB, free: 8.391 MB / 0.4981 GB
Notification: Performance of preOpt comSubExp (simulation): time 0.001809/1.179, allocations: 0.6716 MB / 0.696 GB, free: 8.047 MB / 0.4981 GB
Notification: Performance of preOpt resolveLoops (simulation): time 0.0007867/1.179, allocations: 364.5 kB / 0.6963 GB, free: 7.867 MB / 0.4981 GB
Notification: Performance of preOpt evalFunc (simulation): time 0.0002434/1.18, allocations: 180.6 kB / 0.6965 GB, free: 7.672 MB / 0.4981 GB
Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 4.434e-05/1.18, allocations: 41.22 kB / 0.6965 GB, free: 7.629 MB / 0.4981 GB
Notification: Performance of preOpt simplifyInStream (simulation): time 0.001193/1.181, allocations: 155.7 kB / 0.6967 GB, free: 7.547 MB / 0.4981 GB
Notification: Performance of pre-optimization done (n=47): time 1.289e-05/1.181, allocations: 3.984 kB / 0.6967 GB, free: 7.543 MB / 0.4981 GB
Notification: Performance of matching and sorting (n=47): time 0.007952/1.189, allocations: 1.794 MB / 0.6984 GB, free: 6.582 MB / 0.4981 GB
Notification: Performance of inlineWhenForInitialization (initialization): time 0.0002187/1.189, allocations: 289 kB / 0.6987 GB, free: 6.238 MB / 0.4981 GB
Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.003643/1.193, allocations: 1.446 MB / 0.7001 GB, free: 5.445 MB / 0.4981 GB
Notification: Performance of collectPreVariables (initialization): time 0.0001704/1.193, allocations: 36.58 kB / 0.7002 GB, free: 5.406 MB / 0.4981 GB
Notification: Performance of collectInitialEqns (initialization): time 0.0006948/1.194, allocations: 0.5887 MB / 0.7007 GB, free: 4.891 MB / 0.4981 GB
Notification: Performance of collectInitialBindings (initialization): time 0.0002186/1.194, allocations: 166.9 kB / 0.7009 GB, free: 4.75 MB / 0.4981 GB
Notification: Performance of simplifyInitialFunctions (initialization): time 0.0001609/1.194, allocations: 70.31 kB / 0.701 GB, free: 4.699 MB / 0.4981 GB
Notification: Performance of setup shared object (initialization): time 0.0001781/1.194, allocations: 332.1 kB / 0.7013 GB, free: 4.375 MB / 0.4981 GB
Notification: Performance of preBalanceInitialSystem (initialization): time 0.0009532/1.195, allocations: 390.3 kB / 0.7016 GB, free: 4.188 MB / 0.4981 GB
Notification: Performance of partitionIndependentBlocks (initialization): time 0.001204/1.197, allocations: 0.6438 MB / 0.7023 GB, free: 3.688 MB / 0.4981 GB
Notification: Performance of analyzeInitialSystem (initialization): time 0.002033/1.199, allocations: 0.8864 MB / 0.7031 GB, free: 3.172 MB / 0.4981 GB
Notification: Performance of solveInitialSystemEqSystem (initialization): time 9.939e-06/1.199, allocations: 2.875 kB / 0.7031 GB, free: 3.172 MB / 0.4981 GB
Notification: Performance of matching and sorting (n=85) (initialization): time 0.003443/1.202, allocations: 1.233 MB / 0.7043 GB, free: 2.57 MB / 0.4981 GB
Notification: Performance of prepare postOptimizeDAE: time 0.0001874/1.202, allocations: 210.2 kB / 0.7045 GB, free: 2.328 MB / 0.4981 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 3.272e-05/1.202, allocations: 6.438 kB / 0.7046 GB, free: 2.328 MB / 0.4981 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.004629/1.207, allocations: 0.6207 MB / 0.7052 GB, free: 2.051 MB / 0.4981 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0007378/1.208, allocations: 156.2 kB / 0.7053 GB, free: 2.016 MB / 0.4981 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.001513/1.209, allocations: 0.9377 MB / 0.7062 GB, free: 1.242 MB / 0.4981 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.001797/1.211, allocations: 90.52 kB / 0.7063 GB, free: 1.156 MB / 0.4981 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0001482/1.211, allocations: 39.97 kB / 0.7064 GB, free: 1.117 MB / 0.4981 GB
Notification: Performance of prepare postOptimizeDAE: time 1.339e-05/1.211, allocations: 4 kB / 0.7064 GB, free: 1.113 MB / 0.4981 GB
Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.002225/1.213, allocations: 0.9365 MB / 0.7073 GB, free: 204 kB / 0.4981 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 2.209e-05/1.214, allocations: 8 kB / 0.7073 GB, free: 196 kB / 0.4981 GB
Notification: Performance of postOpt tearingSystem (initialization): time 1.456e-05/1.214, allocations: 8 kB / 0.7073 GB, free: 188 kB / 0.4981 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0008929/1.214, allocations: 190.6 kB / 0.7075 GB, free: 8 kB / 0.4981 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 5.769e-05/1.215, allocations: 12.03 kB / 0.7075 GB, free: 15.99 MB / 0.5137 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.001698/1.216, allocations: 87.73 kB / 0.7076 GB, free: 15.91 MB / 0.5137 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.000115/1.216, allocations: 39.97 kB / 0.7076 GB, free: 15.87 MB / 0.5137 GB
Notification: Model statistics after passing the back-end for initialization:
 * Number of independent subsystems: 17
 * Number of states: 0 ()
 * Number of discrete variables: 0 ()
 * Number of discrete states: 0 ()
 * Number of clocked states: 0 ()
 * Top-level inputs: 0
Notification: Strong component statistics for initialization (69):
 * Single equations (assignments): 64
 * Array equations: 2
 * Algorithm blocks: 0
 * Record equations: 2
 * When equations: 0
 * If-equations: 0
 * Equation systems (not torn): 0
 * Torn equation systems: 1
 * Mixed (continuous/discrete) equation systems: 0
Notification: Torn system details for strict tearing set:
 * Linear torn systems (#iteration vars, #inner vars, density): 0 systems
 * Non-linear torn systems (#iteration vars, #inner vars): 1 system
   {(2,11)}
Notification: Performance of prepare postOptimizeDAE: time 0.0008537/1.217, allocations: 375.8 kB / 0.708 GB, free: 15.5 MB / 0.5137 GB
Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0006286/1.218, allocations: 134.3 kB / 0.7081 GB, free: 15.37 MB / 0.5137 GB
Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.00332/1.221, allocations: 1.08 MB / 0.7091 GB, free: 14.28 MB / 0.5137 GB
Notification: Performance of postOpt inlineArrayEqn (simulation): time 1.266e-05/1.221, allocations: 7.938 kB / 0.7091 GB, free: 14.27 MB / 0.5137 GB
Notification: Performance of postOpt constantLinearSystem (simulation): time 1.139e-05/1.221, allocations: 0 / 0.7091 GB, free: 14.27 MB / 0.5137 GB
Notification: Performance of postOpt simplifysemiLinear (simulation): time 1.201e-05/1.221, allocations: 3.984 kB / 0.7092 GB, free: 14.27 MB / 0.5137 GB
Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.004706/1.226, allocations: 2.083 MB / 0.7112 GB, free: 12.14 MB / 0.5137 GB
Notification: Performance of postOpt simplifyComplexFunction (simulation): time 4.689e-06/1.226, allocations: 0 / 0.7112 GB, free: 12.14 MB / 0.5137 GB
Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0005038/1.226, allocations: 101 kB / 0.7113 GB, free: 12.04 MB / 0.5137 GB
Notification: Performance of postOpt tearingSystem (simulation): time 0.002878/1.229, allocations: 464.2 kB / 0.7117 GB, free: 11.59 MB / 0.5137 GB
Notification: Performance of postOpt inputDerivativesUsed (simulation): time 7.091e-05/1.229, allocations: 19.98 kB / 0.7117 GB, free: 11.57 MB / 0.5137 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.001197/1.231, allocations: 0.8223 MB / 0.7125 GB, free: 10.72 MB / 0.5137 GB
Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 1.08e-05/1.231, allocations: 7.969 kB / 0.7126 GB, free: 10.71 MB / 0.5137 GB
Notification: Performance of postOpt symbolicJacobian (simulation): time 0.003558/1.234, allocations: 1.473 MB / 0.714 GB, free: 9.219 MB / 0.5137 GB
Notification: Performance of postOpt removeConstants (simulation): time 0.0009034/1.235, allocations: 255.4 kB / 0.7142 GB, free: 8.949 MB / 0.5137 GB
Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0004986/1.236, allocations: 23.98 kB / 0.7143 GB, free: 8.926 MB / 0.5137 GB
Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.001223/1.237, allocations: 55.89 kB / 0.7143 GB, free: 8.871 MB / 0.5137 GB
Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0001612/1.237, allocations: 47.03 kB / 0.7144 GB, free: 8.828 MB / 0.5137 GB
Notification: Performance of postOpt collapseArrayExpressions (simulation): time 7.287e-05/1.237, allocations: 19.98 kB / 0.7144 GB, free: 8.809 MB / 0.5137 GB
Notification: Performance of sorting global known variables: time 0.002101/1.239, allocations: 1.007 MB / 0.7154 GB, free: 7.801 MB / 0.5137 GB
Notification: Performance of sort global known variables: time 4.51e-07/1.239, allocations: 0 / 0.7154 GB, free: 7.801 MB / 0.5137 GB
Notification: Performance of remove unused functions: time 0.003039/1.242, allocations: 0.6435 MB / 0.716 GB, free: 7.156 MB / 0.5137 GB
Notification: Model statistics after passing the back-end for simulation:
 * Number of independent subsystems: 2
 * Number of states: 4 (mixBox.filter.x[1],mixBox.filter.x[2],mixBox.filterOutMin.x[1],mixBox.filterOutMin.x[2])
 * Number of discrete variables: 0 ()
 * Number of discrete states: 0 ()
 * Number of clocked states: 0 ()
 * Top-level inputs: 0
Notification: Strong component statistics for simulation (42):
 * Single equations (assignments): 41
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 0
 * When equations: 0
 * If-equations: 0
 * Equation systems (not torn): 0
 * Torn equation systems: 1
 * Mixed (continuous/discrete) equation systems: 0
Notification: Torn system details for strict tearing set:
 * Linear torn systems (#iteration vars, #inner vars, density): 0 systems
 * Non-linear torn systems (#iteration vars, #inner vars): 1 system
   {(2,15)}
Notification: Performance of Backend phase and start with SimCode phase: time 0.001706/1.244, allocations: 447.7 kB / 0.7164 GB, free: 6.746 MB / 0.5137 GB
Notification: Performance of simCode: created initialization part: time 0.0037/1.248, allocations: 1.482 MB / 0.7179 GB, free: 5.27 MB / 0.5137 GB
Notification: Performance of simCode: created event and clocks part: time 7.785e-06/1.248, allocations: 2.891 kB / 0.7179 GB, free: 5.27 MB / 0.5137 GB
Notification: Performance of simCode: created simulation system equations: time 0.001123/1.249, allocations: 415 kB / 0.7183 GB, free: 4.871 MB / 0.5137 GB
Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.003827/1.253, allocations: 492 kB / 0.7187 GB, free: 4.402 MB / 0.5137 GB
Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.006623/1.259, allocations: 2.524 MB / 0.7212 GB, free: 1.852 MB / 0.5137 GB
Notification: Performance of simCode: some other stuff during SimCode phase: time 0.001104/1.261, allocations: 1.125 MB / 0.7223 GB, free: 0.6914 MB / 0.5137 GB
Notification: Performance of simCode: alias equations: time 0.001807/1.262, allocations: 321.6 kB / 0.7226 GB, free: 396 kB / 0.5137 GB
Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0005878/1.263, allocations: 107.4 kB / 0.7227 GB, free: 288 kB / 0.5137 GB
Notification: Performance of SimCode: time 1.233e-06/1.263, allocations: 0 / 0.7227 GB, free: 288 kB / 0.5137 GB
Notification: Performance of Templates: time 0.07102/1.334, allocations: 28.07 MB / 0.7501 GB, free: 4.496 MB / 0.545 GB
make -j1 -f Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow.makefile
Environment - environmentSimulation:
(rm -f Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow.pipe ; mkfifo Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow.pipe ; head -c 1048576 < Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow.pipe >> ../files/Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow.sim & ./Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow  -abortSlowSimulation -alarm=480 -lv LOG_STATS > Buildings_1.6_Buildings.Fluid.Actuators.Dampers.Examples.MixingBoxMinimumFlow.pipe 2>&1)
Environment - environmentSimulation: