Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr OpenIPSL_OpenIPSL.Examples.Tutorial.Example_1.Example_1.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/Modelica 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/OpenIPSL 3.0.1/package.mo", uses=false) Using package OpenIPSL with version 3.0.1 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/OpenIPSL 3.0.1/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 Modelica with version 4.0.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 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: "" <> buildModelFMU(OpenIPSL.Examples.Tutorial.Example_1.Example_1,fileNamePrefix="OpenIPSL_OpenIPSL_Examples_Tutorial_Example_1_Example_1",fmuType="me",version="2.0",platforms={"static"}) "" <> buildModelFMU(OpenIPSL.Examples.Tutorial.Example_1.Example_1,fileNamePrefix="OpenIPSL_OpenIPSL_Examples_Tutorial_Example_1_Example_1",fmuType="me",version="2.0",platforms={"static"}) Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.00106/0.00106, allocations: 100.3 kB / 15.05 MB, free: 1.105 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 4.0.0+maint.om/package.mo): time 1.493/1.493, allocations: 223.2 MB / 238.9 MB, free: 5.484 MB / 190.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.00114/0.00114, allocations: 181 kB / 290.2 MB, free: 2.172 MB / 238.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/OpenIPSL 3.0.1/package.mo): time 0.7505/0.7505, allocations: 78.53 MB / 419.8 MB, free: 4.312 MB / 286.1 MB Notification: Performance of FrontEnd - loaded program: time 0.0004085/0.0004089, allocations: 12 kB / 499.8 MB, free: 6.281 MB / 366.1 MB Notification: Performance of FrontEnd - Absyn->SCode: time 0.1831/0.1835, allocations: 69.36 MB / 0.5558 GB, free: 0.8828 MB / 430.1 MB Notification: Performance of NFInst.instantiate(OpenIPSL.Examples.Tutorial.Example_1.Example_1): time 0.3577/0.5413, allocations: 4.544 MB / 0.5602 GB, free: 37.39 MB / 430.1 MB Notification: Performance of NFInst.instExpressions: time 0.004187/0.5456, allocations: 1.7 MB / 0.5619 GB, free: 37.17 MB / 430.1 MB Notification: Performance of NFInst.updateImplicitVariability: time 0.0008598/0.5465, allocations: 9 kB / 0.5619 GB, free: 37.17 MB / 430.1 MB Notification: Performance of NFTyping.typeComponents: time 0.0004773/0.547, allocations: 126.3 kB / 0.562 GB, free: 37.12 MB / 430.1 MB [/home/hudson/saved_omc/libraries/.openmodelica/libraries/OpenIPSL 3.0.1/Electrical/Branches/PSAT/TwoWindingTransformer.mo:44:3-44:83:writable] Warning: In relation transformer.m <> 1.0, <> on Real numbers is only allowed inside functions. Notification: Performance of NFTyping.typeBindings: time 0.001871/0.5489, allocations: 0.5679 MB / 0.5626 GB, free: 37.06 MB / 430.1 MB Notification: Performance of NFTyping.typeClassSections: time 0.001007/0.5499, allocations: 384.5 kB / 0.5629 GB, free: 37.04 MB / 430.1 MB Notification: Performance of NFFlatten.flatten: time 0.001895/0.5518, allocations: 0.7305 MB / 0.5636 GB, free: 37.01 MB / 430.1 MB Notification: Performance of NFFlatten.resolveConnections: time 0.000455/0.5522, allocations: 188.2 kB / 0.5638 GB, free: 36.96 MB / 430.1 MB Notification: Performance of NFEvalConstants.evaluate: time 0.0008308/0.5531, allocations: 400.2 kB / 0.5642 GB, free: 36.89 MB / 430.1 MB Notification: Performance of NFSimplifyModel.simplify: time 0.000685/0.5538, allocations: 0.5097 MB / 0.5647 GB, free: 36.79 MB / 430.1 MB Notification: Performance of NFPackage.collectConstants: time 0.0001265/0.5539, allocations: 53.75 kB / 0.5647 GB, free: 36.79 MB / 430.1 MB Notification: Performance of NFFlatten.collectFunctions: time 0.0005272/0.5544, allocations: 159.1 kB / 0.5649 GB, free: 36.79 MB / 430.1 MB Notification: Performance of NFScalarize.scalarize: time 0.0001773/0.5546, allocations: 181 kB / 0.5651 GB, free: 36.76 MB / 430.1 MB Notification: Performance of NFVerifyModel.verify: time 0.000193/0.5548, allocations: 180.4 kB / 0.5652 GB, free: 36.69 MB / 430.1 MB Notification: Performance of NFConvertDAE.convert: time 0.001119/0.556, allocations: 1.046 MB / 0.5663 GB, free: 36.62 MB / 430.1 MB Notification: Performance of FrontEnd - DAE generated: time 3.096e-06/0.556, allocations: 0 / 0.5663 GB, free: 36.62 MB / 430.1 MB Notification: Performance of FrontEnd: time 2.736e-06/0.556, allocations: 0 / 0.5663 GB, free: 36.62 MB / 430.1 MB Notification: Performance of Transformations before backend: time 1.14e-05/0.556, allocations: 0 / 0.5663 GB, free: 36.62 MB / 430.1 MB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 132 * Number of variables: 132 Notification: Performance of Generate backend data structure: time 0.00539/0.5614, allocations: 1.717 MB / 0.5679 GB, free: 35.92 MB / 430.1 MB Notification: Performance of prepare preOptimizeDAE: time 5.337e-05/0.5615, allocations: 9.469 kB / 0.5679 GB, free: 35.92 MB / 430.1 MB Notification: Performance of preOpt introduceOutputAliases (simulation): time 0.0001982/0.5617, allocations: 95.17 kB / 0.568 GB, free: 35.88 MB / 430.1 MB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.003413/0.5651, allocations: 0.5289 MB / 0.5686 GB, free: 35.83 MB / 430.1 MB Notification: Performance of preOpt evaluateParameters (simulation): time 0.001181/0.5663, allocations: 0.655 MB / 0.5692 GB, free: 35.54 MB / 430.1 MB Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0001962/0.5665, allocations: 151 kB / 0.5693 GB, free: 35.45 MB / 430.1 MB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0001329/0.5666, allocations: 62.81 kB / 0.5694 GB, free: 35.44 MB / 430.1 MB Notification: Performance of preOpt clockPartitioning (simulation): time 0.001733/0.5684, allocations: 0.8232 MB / 0.5702 GB, free: 35.37 MB / 430.1 MB Notification: Performance of preOpt findStateOrder (simulation): time 1.903e-05/0.5684, allocations: 0 / 0.5702 GB, free: 35.37 MB / 430.1 MB Notification: Performance of preOpt replaceEdgeChange (simulation): time 8.305e-05/0.5685, allocations: 22.2 kB / 0.5702 GB, free: 35.37 MB / 430.1 MB Notification: Performance of preOpt inlineArrayEqn (simulation): time 1.507e-05/0.5685, allocations: 14.47 kB / 0.5702 GB, free: 35.37 MB / 430.1 MB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.001362/0.5699, allocations: 0.7245 MB / 0.5709 GB, free: 35.36 MB / 430.1 MB 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 0.005349/0.5753, allocations: 3.046 MB / 0.5739 GB, free: 34.15 MB / 430.1 MB Notification: Performance of preOpt comSubExp (simulation): time 0.01334/0.5886, allocations: 3.914 MB / 0.5777 GB, free: 33.49 MB / 430.1 MB Notification: Performance of preOpt evalFunc (simulation): time 0.0001838/0.5888, allocations: 10.5 kB / 0.5778 GB, free: 33.49 MB / 430.1 MB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 4.42e-05/0.5889, allocations: 42.42 kB / 0.5778 GB, free: 33.45 MB / 430.1 MB Notification: Performance of pre-optimization done (n=64): time 2.926e-06/0.5889, allocations: 4 kB / 0.5778 GB, free: 33.44 MB / 430.1 MB Notification: Performance of matching and sorting (n=64): time 0.01261/0.6015, allocations: 3.898 MB / 0.5816 GB, free: 32.36 MB / 430.1 MB Notification: Performance of inlineWhenForInitialization (initialization): time 5.913e-05/0.6016, allocations: 89.27 kB / 0.5817 GB, free: 32.26 MB / 430.1 MB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.001517/0.6032, allocations: 0.783 MB / 0.5825 GB, free: 31.9 MB / 430.1 MB Notification: Performance of collectPreVariables (initialization): time 0.0002317/0.6034, allocations: 40.36 kB / 0.5825 GB, free: 31.86 MB / 430.1 MB Notification: Performance of collectInitialEqns (initialization): time 0.0003137/0.6037, allocations: 377.5 kB / 0.5829 GB, free: 31.57 MB / 430.1 MB Notification: Performance of collectInitialBindings (initialization): time 0.0002846/0.604, allocations: 238 kB / 0.5831 GB, free: 31.39 MB / 430.1 MB Notification: Performance of simplifyInitialFunctions (initialization): time 6.815e-05/0.6041, allocations: 15.88 kB / 0.5831 GB, free: 31.38 MB / 430.1 MB Notification: Performance of setup shared object (initialization): time 0.000118/0.6042, allocations: 341.2 kB / 0.5834 GB, free: 31.05 MB / 430.1 MB Notification: Performance of preBalanceInitialSystem (initialization): time 0.001301/0.6055, allocations: 0.5809 MB / 0.584 GB, free: 30.83 MB / 430.1 MB Notification: Performance of partitionIndependentBlocks (initialization): time 0.001331/0.6069, allocations: 0.6919 MB / 0.5847 GB, free: 30.51 MB / 430.1 MB Notification: Performance of analyzeInitialSystem (initialization): time 0.001321/0.6082, allocations: 0.6337 MB / 0.5853 GB, free: 30.23 MB / 430.1 MB Notification: Performance of solveInitialSystemEqSystem (initialization): time 5.641e-06/0.6082, allocations: 0 / 0.5853 GB, free: 30.23 MB / 430.1 MB Notification: Performance of matching and sorting (n=125) (initialization): time 0.009003/0.6172, allocations: 2.872 MB / 0.5881 GB, free: 29.4 MB / 430.1 MB Notification: Performance of prepare postOptimizeDAE: time 0.0003064/0.6176, allocations: 0.7109 MB / 0.5888 GB, free: 28.65 MB / 430.1 MB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.785e-05/0.6176, allocations: 2.031 kB / 0.5888 GB, free: 28.65 MB / 430.1 MB Notification: Performance of postOpt tearingSystem (initialization): time 0.005206/0.6228, allocations: 1.265 MB / 0.59 GB, free: 28.42 MB / 430.1 MB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001171/0.624, allocations: 175.5 kB / 0.5902 GB, free: 28.4 MB / 430.1 MB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.01244/0.6365, allocations: 5.602 MB / 0.5957 GB, free: 25.56 MB / 430.1 MB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.001602/0.6381, allocations: 138.6 kB / 0.5958 GB, free: 25.51 MB / 430.1 MB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0001073/0.6382, allocations: 35.62 kB / 0.5958 GB, free: 25.5 MB / 430.1 MB Notification: Performance of prepare postOptimizeDAE: time 1.274e-05/0.6382, allocations: 2.781 kB / 0.5958 GB, free: 25.5 MB / 430.1 MB Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.008222/0.6465, allocations: 2.743 MB / 0.5985 GB, free: 24.73 MB / 430.1 MB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.748e-05/0.6465, allocations: 1.062 kB / 0.5985 GB, free: 24.73 MB / 430.1 MB Notification: Performance of postOpt tearingSystem (initialization): time 0.005077/0.6516, allocations: 1.254 MB / 0.5997 GB, free: 24.51 MB / 430.1 MB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001068/0.6527, allocations: 173.4 kB / 0.5999 GB, free: 24.49 MB / 430.1 MB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.0127/0.6654, allocations: 5.6 MB / 0.6054 GB, free: 21.65 MB / 430.1 MB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.001672/0.6671, allocations: 125.8 kB / 0.6055 GB, free: 21.6 MB / 430.1 MB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 9.969e-05/0.6673, allocations: 34.61 kB / 0.6055 GB, free: 21.59 MB / 430.1 MB Warning: Assuming fixed start value for the following 2 variables: G1.machine.w:VARIABLE(flow=false start = 1.0 fixed = true ) "Rotor speed [pu]" type: Real G1.avr.vref:VARIABLE(unit = "1" fixed = true protected = true ) type: Real Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 8 * 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 (103): * Single equations (assignments): 100 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 2 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Equation system details: * Constant Jacobian: 0 * Linear Jacobian (size,density): 2 {(2,100.0%),(2,100.0%)} * Non-linear Jacobian: 0 * Without analytic Jacobian: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 1 {8 13} Notification: Performance of prepare postOptimizeDAE: time 0.0006409/0.6679, allocations: 298.6 kB / 0.6058 GB, free: 21.33 MB / 430.1 MB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0002499/0.6682, allocations: 92.31 kB / 0.6059 GB, free: 21.28 MB / 430.1 MB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.006965/0.6751, allocations: 2.392 MB / 0.6082 GB, free: 20.62 MB / 430.1 MB Notification: Performance of postOpt inlineArrayEqn (simulation): time 1.47e-05/0.6752, allocations: 6.25 kB / 0.6082 GB, free: 20.62 MB / 430.1 MB Notification: Performance of postOpt constantLinearSystem (simulation): time 1.602e-05/0.6752, allocations: 3.875 kB / 0.6082 GB, free: 20.62 MB / 430.1 MB Notification: Performance of postOpt simplifysemiLinear (simulation): time 1.773e-05/0.6752, allocations: 8.031 kB / 0.6082 GB, free: 20.62 MB / 430.1 MB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.008926/0.6841, allocations: 3.671 MB / 0.6118 GB, free: 19.19 MB / 430.1 MB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 6.622e-06/0.6842, allocations: 0 / 0.6118 GB, free: 19.19 MB / 430.1 MB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0005792/0.6848, allocations: 87.25 kB / 0.6119 GB, free: 19.18 MB / 430.1 MB Notification: Performance of postOpt tearingSystem (simulation): time 0.003392/0.6882, allocations: 1.084 MB / 0.613 GB, free: 18.38 MB / 430.1 MB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 8.014e-05/0.6883, allocations: 22 kB / 0.613 GB, free: 18.36 MB / 430.1 MB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.007789/0.6961, allocations: 4.306 MB / 0.6172 GB, free: 14.43 MB / 430.1 MB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 3.397e-06/0.6961, allocations: 4 kB / 0.6172 GB, free: 14.43 MB / 430.1 MB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.006797/0.7029, allocations: 3.088 MB / 0.6202 GB, free: 11.29 MB / 430.1 MB Notification: Performance of postOpt removeConstants (simulation): time 0.0003702/0.7033, allocations: 183.8 kB / 0.6204 GB, free: 11.09 MB / 430.1 MB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0001358/0.7035, allocations: 12.81 kB / 0.6204 GB, free: 11.08 MB / 430.1 MB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.0007812/0.7042, allocations: 83.92 kB / 0.6205 GB, free: 11 MB / 430.1 MB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0003354/0.7046, allocations: 124.3 kB / 0.6206 GB, free: 10.88 MB / 430.1 MB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 4.766e-05/0.7046, allocations: 19.95 kB / 0.6206 GB, free: 10.86 MB / 430.1 MB Notification: Performance of sorting global known variables: time 0.0006016/0.7052, allocations: 0.5303 MB / 0.6211 GB, free: 10.34 MB / 430.1 MB Notification: Performance of sort global known variables: time 2.7e-07/0.7053, allocations: 0 / 0.6211 GB, free: 10.34 MB / 430.1 MB Notification: Performance of remove unused functions: time 0.001531/0.7068, allocations: 0.5228 MB / 0.6216 GB, free: 9.812 MB / 430.1 MB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 3 * Number of states: 9 (G1.avr.vm,G1.avr.vr,G1.avr.vf1,G1.machine.delta,G1.machine.w,G1.machine.e1q,G1.machine.e1d,G1.machine.e2q,G1.machine.e2d) * 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 (47): * Single equations (assignments): 44 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 2 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Equation system details: * Constant Jacobian: 0 * Linear Jacobian (size,density): 2 {(2,100.0%),(2,100.0%)} * Non-linear Jacobian: 0 * Without analytic Jacobian: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 1 {(9,48.1%) 9} * Non-linear torn systems: 0 Notification: Performance of Backend phase and start with SimCode phase: time 0.006774/0.7136, allocations: 3.791 MB / 0.6254 GB, free: 5.977 MB / 430.1 MB Notification: Performance of simCode: created initialization part: time 0.007486/0.7211, allocations: 3.565 MB / 0.6288 GB, free: 2.312 MB / 430.1 MB Notification: Performance of simCode: created event and clocks part: time 5.44e-06/0.7211, allocations: 4.125 kB / 0.6288 GB, free: 2.309 MB / 430.1 MB Notification: Performance of simCode: created simulation system equations: time 0.002635/0.7238, allocations: 1.264 MB / 0.6301 GB, free: 0.9922 MB / 430.1 MB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.0006784/0.7245, allocations: 57.34 kB / 0.6301 GB, free: 0.9375 MB / 430.1 MB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.005244/0.7297, allocations: 3.612 MB / 0.6337 GB, free: 13.28 MB / 446.1 MB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.0005855/0.7303, allocations: 0.999 MB / 0.6346 GB, free: 12.25 MB / 446.1 MB Notification: Performance of simCode: alias equations: time 0.0004375/0.7308, allocations: 94.02 kB / 0.6347 GB, free: 12.16 MB / 446.1 MB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0004545/0.7313, allocations: 307.3 kB / 0.635 GB, free: 11.86 MB / 446.1 MB Notification: Performance of SimCode: time 2.255e-06/0.7313, allocations: 0 / 0.635 GB, free: 11.86 MB / 446.1 MB Notification: Performance of buildModelFMU: Generate the FMI files: time 0.04808/0.7794, allocations: 26.4 MB / 0.6608 GB, free: 1.852 MB / 462.1 MB Notification: Performance of buildModelFMU: configured platform static using cached values: time 0.0001992/0.7796, allocations: 215.3 kB / 0.661 GB, free: 1.602 MB / 462.1 MB Notification: Performance of buildModelFMU: Generate platform static: time 2.779/3.559, allocations: 3 kB / 0.661 GB, free: 1.602 MB / 462.1 MB (rm -f OpenIPSL_OpenIPSL.Examples.Tutorial.Example_1.Example_1.pipe ; mkfifo OpenIPSL_OpenIPSL.Examples.Tutorial.Example_1.Example_1.pipe ; head -c 1048576 < OpenIPSL_OpenIPSL.Examples.Tutorial.Example_1.Example_1.pipe >> ../files/OpenIPSL_OpenIPSL.Examples.Tutorial.Example_1.Example_1.sim & /home/hudson/saved_omc/OMSimulator/install/linux/bin/OMSimulator --tempDir=temp_OpenIPSL_OpenIPSL_Examples_Tutorial_Example_1_Example_1_fmu --startTime=0 --stopTime=10 --timeout=50 --tolerance=1e-06 OpenIPSL_OpenIPSL_Examples_Tutorial_Example_1_Example_1.fmu > OpenIPSL_OpenIPSL.Examples.Tutorial.Example_1.Example_1.pipe 2>&1) Environment - environmentSimulation: