Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr IDEAS_dev_IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent.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 4.0.0+maint.om/package.mo", uses=false) loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/IDEAS 3.0.0-master/package.mo", uses=false) Using package IDEAS with version 3.0.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/IDEAS 3.0.0-master/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 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: "" <> buildModelFMU(IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent,fileNamePrefix="IDEAS_dev_IDEAS_Fluid_Actuators_Dampers_Validation_PressureIndependent",fmuType="me",version="2.0",platforms={"static"}) "" <> buildModelFMU(IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent,fileNamePrefix="IDEAS_dev_IDEAS_Fluid_Actuators_Dampers_Validation_PressureIndependent",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 0.00102/0.00102, allocations: 84.38 kB / 15.06 MB, free: 1.09 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.001133/0.001133, allocations: 168.7 kB / 15.95 MB, free: 204 kB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 4.0.0+maint.om/package.mo): time 1.489/1.489, allocations: 223.3 MB / 240 MB, free: 5.391 MB / 190.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/IDEAS 3.0.0-master/package.mo): time 1.037/1.037, allocations: 135.3 MB / 426.4 MB, free: 14.1 MB / 350.1 MB Notification: Performance of FrontEnd - loaded program: time 0.0004071/0.0004074, allocations: 12.77 kB / 0.5071 GB, free: 5.035 MB / 414.1 MB Notification: Performance of FrontEnd - Absyn->SCode: time 0.2483/0.2487, allocations: 82.31 MB / 0.5875 GB, free: 2.895 MB / 494.1 MB Notification: Performance of NFInst.instantiate(IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent): time 0.6896/0.9383, allocations: 167.4 MB / 0.7509 GB, free: 4.344 MB / 0.5606 GB Notification: Performance of NFInst.instExpressions: time 0.01689/0.9553, allocations: 9.711 MB / 0.7604 GB, free: 11.82 MB / 0.5762 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.002477/0.9578, allocations: 27.81 kB / 0.7604 GB, free: 11.8 MB / 0.5762 GB Notification: Performance of NFTyping.typeComponents: time 0.00197/0.9598, allocations: 309.8 kB / 0.7607 GB, free: 11.49 MB / 0.5762 GB Notification: Performance of NFTyping.typeBindings: time 0.005128/0.965, allocations: 1.007 MB / 0.7617 GB, free: 10.48 MB / 0.5762 GB Notification: Performance of NFTyping.typeClassSections: time 0.005912/0.9709, allocations: 1.382 MB / 0.7631 GB, free: 9.117 MB / 0.5762 GB Notification: Performance of NFFlatten.flatten: time 0.004889/0.9758, allocations: 2.739 MB / 0.7657 GB, free: 6.367 MB / 0.5762 GB Notification: Performance of NFFlatten.resolveConnections: time 0.002302/0.9781, allocations: 0.8548 MB / 0.7666 GB, free: 5.5 MB / 0.5762 GB Notification: Performance of NFEvalConstants.evaluate: time 0.003336/0.9815, allocations: 1.078 MB / 0.7676 GB, free: 4.418 MB / 0.5762 GB Notification: Performance of NFSimplifyModel.simplify: time 0.002507/0.984, allocations: 1.156 MB / 0.7688 GB, free: 3.258 MB / 0.5762 GB Notification: Performance of NFPackage.collectConstants: time 0.0009747/0.985, allocations: 80 kB / 0.7688 GB, free: 3.18 MB / 0.5762 GB Notification: Performance of NFFlatten.collectFunctions: time 0.004346/0.9894, allocations: 1.146 MB / 0.77 GB, free: 2.031 MB / 0.5762 GB Notification: Performance of NFScalarize.scalarize: time 0.001379/0.9908, allocations: 494.4 kB / 0.7704 GB, free: 1.547 MB / 0.5762 GB Notification: Performance of NFVerifyModel.verify: time 0.001174/0.992, allocations: 260.9 kB / 0.7707 GB, free: 1.285 MB / 0.5762 GB Notification: Performance of NFConvertDAE.convert: time 0.003906/0.9959, allocations: 1.917 MB / 0.7725 GB, free: 15.36 MB / 0.5919 GB Notification: Performance of FrontEnd - DAE generated: time 6.422e-06/0.9959, allocations: 0 / 0.7725 GB, free: 15.36 MB / 0.5919 GB Notification: Performance of FrontEnd: time 3.045e-06/0.9959, allocations: 0 / 0.7725 GB, free: 15.36 MB / 0.5919 GB Notification: Performance of Transformations before backend: time 0.0001083/0.996, allocations: 0 / 0.7725 GB, free: 15.36 MB / 0.5919 GB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 174 * Number of variables: 174 Notification: Performance of Generate backend data structure: time 0.006629/1.003, allocations: 1.95 MB / 0.7745 GB, free: 13.36 MB / 0.5919 GB Notification: Performance of prepare preOptimizeDAE: time 5.843e-05/1.003, allocations: 8.031 kB / 0.7745 GB, free: 13.36 MB / 0.5919 GB Notification: Performance of preOpt introduceOutputAliases (simulation): time 0.0003735/1.003, allocations: 114.5 kB / 0.7746 GB, free: 13.23 MB / 0.5919 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.001819/1.005, allocations: 229.9 kB / 0.7748 GB, free: 13.01 MB / 0.5919 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.004031/1.009, allocations: 1.349 MB / 0.7761 GB, free: 11.61 MB / 0.5919 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 9.612e-05/1.009, allocations: 66 kB / 0.7762 GB, free: 11.54 MB / 0.5919 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0004217/1.01, allocations: 87.5 kB / 0.7763 GB, free: 11.46 MB / 0.5919 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.002257/1.012, allocations: 1.01 MB / 0.7772 GB, free: 10.38 MB / 0.5919 GB Notification: Performance of preOpt findStateOrder (simulation): time 2.133e-05/1.012, allocations: 0 / 0.7772 GB, free: 10.38 MB / 0.5919 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 8.012e-05/1.012, allocations: 28 kB / 0.7773 GB, free: 10.36 MB / 0.5919 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 2.179e-05/1.012, allocations: 16 kB / 0.7773 GB, free: 10.34 MB / 0.5919 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.002041/1.014, allocations: 0.93 MB / 0.7782 GB, free: 9.41 MB / 0.5919 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 0.009002/1.023, allocations: 4.764 MB / 0.7828 GB, free: 4.422 MB / 0.5919 GB Notification: Performance of preOpt comSubExp (simulation): time 0.001619/1.025, allocations: 0.7632 MB / 0.7836 GB, free: 3.648 MB / 0.5919 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.0008486/1.026, allocations: 428.8 kB / 0.784 GB, free: 3.23 MB / 0.5919 GB Notification: Performance of preOpt evalFunc (simulation): time 0.0005121/1.026, allocations: 280.6 kB / 0.7843 GB, free: 2.902 MB / 0.5919 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 4.694e-05/1.026, allocations: 39 kB / 0.7843 GB, free: 2.855 MB / 0.5919 GB Notification: Performance of pre-optimization done (n=50): time 5.27e-06/1.026, allocations: 4 kB / 0.7843 GB, free: 2.852 MB / 0.5919 GB Notification: Performance of matching and sorting (n=50): time 0.00534/1.032, allocations: 1.627 MB / 0.7859 GB, free: 1.195 MB / 0.5919 GB Notification: Performance of inlineWhenForInitialization (initialization): time 4.944e-05/1.032, allocations: 55.84 kB / 0.7859 GB, free: 1.129 MB / 0.5919 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.003718/1.035, allocations: 1.828 MB / 0.7877 GB, free: 15.29 MB / 0.6075 GB Notification: Performance of collectPreVariables (initialization): time 0.0003755/1.036, allocations: 41.7 kB / 0.7878 GB, free: 15.24 MB / 0.6075 GB Notification: Performance of collectInitialEqns (initialization): time 0.0008512/1.037, allocations: 0.5871 MB / 0.7883 GB, free: 14.65 MB / 0.6075 GB Notification: Performance of collectInitialBindings (initialization): time 0.0002225/1.037, allocations: 173.5 kB / 0.7885 GB, free: 14.48 MB / 0.6075 GB Notification: Performance of simplifyInitialFunctions (initialization): time 0.0001962/1.037, allocations: 12 kB / 0.7885 GB, free: 14.46 MB / 0.6075 GB Notification: Performance of setup shared object (initialization): time 0.0002061/1.037, allocations: 345.9 kB / 0.7888 GB, free: 14.12 MB / 0.6075 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.001889/1.039, allocations: 0.9584 MB / 0.7898 GB, free: 13.16 MB / 0.6075 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.002216/1.041, allocations: 1.314 MB / 0.7911 GB, free: 11.72 MB / 0.6075 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.001671/1.043, allocations: 0.8535 MB / 0.7919 GB, free: 10.87 MB / 0.6075 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 6.613e-06/1.043, allocations: 0 / 0.7919 GB, free: 10.87 MB / 0.6075 GB Notification: Performance of matching and sorting (n=121) (initialization): time 0.004901/1.048, allocations: 2.192 MB / 0.794 GB, free: 8.66 MB / 0.6075 GB Notification: Performance of prepare postOptimizeDAE: time 0.0002308/1.048, allocations: 233.8 kB / 0.7943 GB, free: 8.371 MB / 0.6075 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 2.849e-05/1.048, allocations: 4 kB / 0.7943 GB, free: 8.367 MB / 0.6075 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.0009584/1.049, allocations: 149.5 kB / 0.7944 GB, free: 8.219 MB / 0.6075 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001069/1.05, allocations: 183.7 kB / 0.7946 GB, free: 8.039 MB / 0.6075 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.001372/1.052, allocations: 1.318 MB / 0.7959 GB, free: 6.672 MB / 0.6075 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.002178/1.054, allocations: 233.8 kB / 0.7961 GB, free: 6.445 MB / 0.6075 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.00014/1.054, allocations: 31.98 kB / 0.7961 GB, free: 6.414 MB / 0.6075 GB Notification: Performance of prepare postOptimizeDAE: time 1.439e-05/1.054, allocations: 4 kB / 0.7961 GB, free: 6.41 MB / 0.6075 GB Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.003786/1.058, allocations: 1.969 MB / 0.7981 GB, free: 4.438 MB / 0.6075 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 2.29e-05/1.058, allocations: 7.984 kB / 0.7981 GB, free: 4.43 MB / 0.6075 GB Notification: Performance of postOpt tearingSystem (initialization): time 2.06e-05/1.058, allocations: 8 kB / 0.7981 GB, free: 4.422 MB / 0.6075 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001009/1.059, allocations: 191.9 kB / 0.7983 GB, free: 4.234 MB / 0.6075 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 1.928e-05/1.059, allocations: 12 kB / 0.7983 GB, free: 4.223 MB / 0.6075 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.00204/1.061, allocations: 206.2 kB / 0.7985 GB, free: 4.023 MB / 0.6075 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0001239/1.061, allocations: 39.92 kB / 0.7985 GB, free: 3.984 MB / 0.6075 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 21 * Number of states: 0 () * Number of discrete variables: 14 (damPreInd.idx_sorted[1],damPreInd.idx_sorted[2],damPreInd.idx_sorted[3],damPreInd.idx_sorted[4],damPreInd.idx_sorted[5],damPreInd.idx_sorted[6],damPreInd.idx_sorted[7],damPreInd.idx_sorted[8],damPreInd.idx_sorted[9],damPreInd.idx_sorted[10],damPreInd.idx_sorted[11],damPreInd.idx_sorted[12],damPreInd.idx_sorted[13],conPID.I.trigger_internal) * Number of discrete states: 0 () * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for initialization (74): * Single equations (assignments): 70 * Array equations: 1 * Algorithm blocks: 0 * Record equations: 1 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 1 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Equation system details: * Constant Jacobian: 0 * Linear Jacobian (size,density): 0 * Non-linear Jacobian: 1 {1} * Without analytic Jacobian: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 1 {1 10} Notification: Performance of prepare postOptimizeDAE: time 0.0008547/1.062, allocations: 388.8 kB / 0.7989 GB, free: 3.594 MB / 0.6075 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0005981/1.063, allocations: 138.2 kB / 0.799 GB, free: 3.457 MB / 0.6075 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.002527/1.065, allocations: 1.042 MB / 0.8 GB, free: 2.414 MB / 0.6075 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 9.388e-06/1.065, allocations: 4 kB / 0.8 GB, free: 2.41 MB / 0.6075 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 8.796e-06/1.065, allocations: 4.188 kB / 0.8 GB, free: 2.406 MB / 0.6075 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 1.007e-05/1.065, allocations: 3.984 kB / 0.8 GB, free: 2.402 MB / 0.6075 GB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.005051/1.07, allocations: 2.284 MB / 0.8023 GB, free: 36 kB / 0.6075 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 8.616e-06/1.07, allocations: 4 kB / 0.8023 GB, free: 32 kB / 0.6075 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0006212/1.071, allocations: 120.1 kB / 0.8024 GB, free: 15.91 MB / 0.6231 GB Notification: Performance of postOpt tearingSystem (simulation): time 0.0007694/1.072, allocations: 146.4 kB / 0.8025 GB, free: 15.77 MB / 0.6231 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 5.902e-05/1.072, allocations: 19.98 kB / 0.8025 GB, free: 15.75 MB / 0.6231 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.001313/1.073, allocations: 1.318 MB / 0.8038 GB, free: 14.38 MB / 0.6231 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 6.222e-06/1.073, allocations: 4 kB / 0.8038 GB, free: 14.38 MB / 0.6231 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.003431/1.077, allocations: 1.626 MB / 0.8054 GB, free: 12.71 MB / 0.6231 GB Notification: Performance of postOpt removeConstants (simulation): time 0.001129/1.078, allocations: 335 kB / 0.8057 GB, free: 12.36 MB / 0.6231 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0006796/1.078, allocations: 8 kB / 0.8057 GB, free: 12.35 MB / 0.6231 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.001541/1.08, allocations: 91.95 kB / 0.8058 GB, free: 12.26 MB / 0.6231 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0001682/1.08, allocations: 52.31 kB / 0.8059 GB, free: 12.21 MB / 0.6231 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 5.929e-05/1.08, allocations: 19.98 kB / 0.8059 GB, free: 12.19 MB / 0.6231 GB Notification: Performance of sorting global known variables: time 0.002769/1.083, allocations: 1.297 MB / 0.8072 GB, free: 10.89 MB / 0.6231 GB Notification: Performance of sort global known variables: time 2.6e-07/1.083, allocations: 0 / 0.8072 GB, free: 10.89 MB / 0.6231 GB Notification: Performance of remove unused functions: time 0.003484/1.086, allocations: 0.6787 MB / 0.8078 GB, free: 10.21 MB / 0.6231 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 8 * Number of states: 2 (conPID.I.y,conPID.D.x) * 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 (44): * Single equations (assignments): 42 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 1 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Equation system details: * Constant Jacobian: 0 * Linear Jacobian (size,density): 0 * Non-linear Jacobian: 1 {1} * Without analytic Jacobian: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 1 {1 11} Notification: Performance of Backend phase and start with SimCode phase: time 0.005336/1.092, allocations: 2.435 MB / 0.8102 GB, free: 7.734 MB / 0.6231 GB Notification: Performance of simCode: created initialization part: time 0.006313/1.098, allocations: 2.789 MB / 0.8129 GB, free: 4.938 MB / 0.6231 GB Notification: Performance of simCode: created event and clocks part: time 1.08e-05/1.098, allocations: 0 / 0.8129 GB, free: 4.938 MB / 0.6231 GB Notification: Performance of simCode: created simulation system equations: time 0.001108/1.099, allocations: 455.2 kB / 0.8134 GB, free: 4.492 MB / 0.6231 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.002957/1.102, allocations: 456.7 kB / 0.8138 GB, free: 4.055 MB / 0.6231 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.02262/1.125, allocations: 11.55 MB / 0.8251 GB, free: 8.117 MB / 0.6387 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.001024/1.126, allocations: 1.174 MB / 0.8262 GB, free: 6.918 MB / 0.6387 GB Notification: Performance of simCode: alias equations: time 0.002347/1.128, allocations: 367.5 kB / 0.8266 GB, free: 6.559 MB / 0.6387 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.000968/1.129, allocations: 0.4915 MB / 0.8271 GB, free: 6.066 MB / 0.6387 GB Notification: Performance of SimCode: time 1.503e-06/1.129, allocations: 0 / 0.8271 GB, free: 6.066 MB / 0.6387 GB Notification: Performance of buildModelFMU: Generate the FMI files: time 0.4461/1.576, allocations: 39.67 MB / 0.8658 GB, free: 212 MB / 0.67 GB Notification: Performance of buildModelFMU: configured platform static using cached values: time 0.0001704/1.576, allocations: 270.6 kB / 0.8661 GB, free: 211.6 MB / 0.67 GB Notification: Performance of buildModelFMU: Generate platform static: time 2.943/4.519, allocations: 0 / 0.8661 GB, free: 211.6 MB / 0.67 GB (rm -f IDEAS_dev_IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent.pipe ; mkfifo IDEAS_dev_IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent.pipe ; head -c 1048576 < IDEAS_dev_IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent.pipe >> ../files/IDEAS_dev_IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent.sim & /home/hudson/saved_omc/OMSimulator/install/linux/bin/OMSimulator --tempDir=temp_IDEAS_dev_IDEAS_Fluid_Actuators_Dampers_Validation_PressureIndependent_fmu --startTime=0 --stopTime=1 --timeout=50 --tolerance=1e-06 IDEAS_dev_IDEAS_Fluid_Actuators_Dampers_Validation_PressureIndependent.fmu > IDEAS_dev_IDEAS.Fluid.Actuators.Dampers.Validation.PressureIndependent.pipe 2>&1) Environment - environmentSimulation: