Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic.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 7.0.3-maint.7.0.x/package.mo", uses=false) Using package Buildings with version 7.0.3 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 7.0.3-maint.7.0.x/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.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic") translateModel(Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic") Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.0008403/0.0008403, allocations: 86.72 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 0.0009821/0.0009822, 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 3.2.3+maint.om/package.mo): time 1.541/1.541, allocations: 205.4 MB / 222.1 MB, free: 5.648 MB / 174.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 7.0.3-maint.7.0.x/package.mo): time 1.585/1.585, allocations: 252 MB / 0.5102 GB, free: 4.789 MB / 414.1 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: Performance of FrontEnd - loaded program: time 0.0006156/0.0006161, allocations: 12 kB / 0.6243 GB, free: 1.121 MB / 0.5137 GB Notification: Performance of FrontEnd - Absyn->SCode: time 0.5539/0.5545, allocations: 106.3 MB / 0.7281 GB, free: 11.43 MB / 0.545 GB Notification: Performance of NFInst.instantiate(Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic): time 0.005136/0.5597, allocations: 3.864 MB / 0.7319 GB, free: 7.551 MB / 0.545 GB Notification: Performance of NFInst.instExpressions: time 0.1525/0.7122, allocations: 136.6 MB / 0.8653 GB, free: 14.59 MB / 0.6856 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.0007002/0.713, allocations: 19.88 kB / 0.8653 GB, free: 14.57 MB / 0.6856 GB Notification: Performance of NFTyping.typeComponents: time 0.0004944/0.7135, allocations: 134.9 kB / 0.8654 GB, free: 14.44 MB / 0.6856 GB [/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 7.0.3-maint.7.0.x/BoundaryConditions/WeatherData/BaseClasses/getHeaderElementTMY3.mo:2:1-105:25:writable] Warning: Pure function ‘Buildings.BoundaryConditions.WeatherData.BaseClasses.getHeaderElementTMY3‘ contains a call to impure function ‘Modelica.Utilities.Streams.readLine‘. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 7.0.3-maint.7.0.x/BoundaryConditions/WeatherData/BaseClasses/getLongitudeTMY3.mo:2:1-48:21:writable] Warning: Pure function ‘Buildings.BoundaryConditions.WeatherData.BaseClasses.getLongitudeTMY3‘ contains a call to impure function ‘Buildings.BoundaryConditions.WeatherData.BaseClasses.getHeaderElementTMY3‘. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 7.0.3-maint.7.0.x/BoundaryConditions/WeatherData/BaseClasses/getLatitudeTMY3.mo:2:1-48:20:writable] Warning: Pure function ‘Buildings.BoundaryConditions.WeatherData.BaseClasses.getLatitudeTMY3‘ contains a call to impure function ‘Buildings.BoundaryConditions.WeatherData.BaseClasses.getHeaderElementTMY3‘. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 7.0.3-maint.7.0.x/BoundaryConditions/WeatherData/BaseClasses/getTimeZoneTMY3.mo:2:1-47:20:writable] Warning: Pure function ‘Buildings.BoundaryConditions.WeatherData.BaseClasses.getTimeZoneTMY3‘ contains a call to impure function ‘Buildings.BoundaryConditions.WeatherData.BaseClasses.getHeaderElementTMY3‘. Notification: Performance of NFTyping.typeBindings: time 0.001329/0.7148, allocations: 376.9 kB / 0.8658 GB, free: 14.07 MB / 0.6856 GB Notification: Performance of NFTyping.typeClassSections: time 0.001663/0.7165, allocations: 0.6009 MB / 0.8664 GB, free: 13.48 MB / 0.6856 GB Notification: Performance of NFFlatten.flatten: time 0.001529/0.718, allocations: 1.12 MB / 0.8675 GB, free: 12.35 MB / 0.6856 GB Notification: Performance of NFFlatten.resolveConnections: time 0.0009025/0.7189, allocations: 0.6701 MB / 0.8681 GB, free: 11.66 MB / 0.6856 GB Notification: Performance of NFEvalConstants.evaluate: time 0.000557/0.7195, allocations: 346.2 kB / 0.8684 GB, free: 11.32 MB / 0.6856 GB Notification: Performance of NFSimplifyModel.simplify: time 0.0004614/0.72, allocations: 361.8 kB / 0.8688 GB, free: 10.96 MB / 0.6856 GB Notification: Performance of NFPackage.collectConstants: time 7.845e-05/0.7201, allocations: 27.98 kB / 0.8688 GB, free: 10.94 MB / 0.6856 GB Notification: Performance of NFFlatten.collectFunctions: time 0.0007126/0.7208, allocations: 267.8 kB / 0.8691 GB, free: 10.68 MB / 0.6856 GB Notification: Performance of NFScalarize.scalarize: time 0.0002133/0.721, allocations: 187 kB / 0.8692 GB, free: 10.49 MB / 0.6856 GB Notification: Performance of NFVerifyModel.verify: time 0.000218/0.7212, allocations: 213.1 kB / 0.8694 GB, free: 10.28 MB / 0.6856 GB Notification: Performance of NFConvertDAE.convert: time 0.001314/0.7226, allocations: 1.27 MB / 0.8707 GB, free: 9.004 MB / 0.6856 GB Notification: Performance of FrontEnd - DAE generated: time 9.287e-06/0.7226, allocations: 0 / 0.8707 GB, free: 9.004 MB / 0.6856 GB Notification: Performance of FrontEnd: time 2.364e-06/0.7226, allocations: 0 / 0.8707 GB, free: 9.004 MB / 0.6856 GB Notification: Performance of Transformations before backend: time 2.158e-05/0.7226, allocations: 0 / 0.8707 GB, free: 9.004 MB / 0.6856 GB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 285 * Number of variables: 285 Notification: Performance of Generate backend data structure: time 0.002667/0.7253, allocations: 1.307 MB / 0.872 GB, free: 7.641 MB / 0.6856 GB Notification: Performance of prepare preOptimizeDAE: time 3.687e-05/0.7253, allocations: 8.031 kB / 0.872 GB, free: 7.633 MB / 0.6856 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.0008685/0.7262, allocations: 218.2 kB / 0.8722 GB, free: 7.418 MB / 0.6856 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.00107/0.7273, allocations: 0.7701 MB / 0.8729 GB, free: 6.605 MB / 0.6856 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 8.386e-05/0.7274, allocations: 82.25 kB / 0.873 GB, free: 6.523 MB / 0.6856 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0001233/0.7275, allocations: 112 kB / 0.8731 GB, free: 6.414 MB / 0.6856 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.002003/0.7295, allocations: 1.106 MB / 0.8742 GB, free: 5.242 MB / 0.6856 GB Notification: Performance of preOpt findStateOrder (simulation): time 2.494e-05/0.7296, allocations: 7.938 kB / 0.8742 GB, free: 5.234 MB / 0.6856 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0001126/0.7297, allocations: 51.95 kB / 0.8743 GB, free: 5.184 MB / 0.6856 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 2.755e-05/0.7297, allocations: 28 kB / 0.8743 GB, free: 5.156 MB / 0.6856 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.002123/0.7319, allocations: 1.214 MB / 0.8755 GB, free: 3.934 MB / 0.6856 GB Notification: Performance of preOpt removeSimpleEquations (simulation): time 0.004906/0.7368, allocations: 3.009 MB / 0.8784 GB, free: 0.8516 MB / 0.6856 GB Notification: Performance of preOpt comSubExp (simulation): time 0.001237/0.738, allocations: 0.7726 MB / 0.8792 GB, free: 72 kB / 0.6856 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.0004945/0.7385, allocations: 298.6 kB / 0.8794 GB, free: 15.78 MB / 0.7012 GB Notification: Performance of preOpt evalFunc (simulation): time 7.851e-05/0.7386, allocations: 28.69 kB / 0.8795 GB, free: 15.75 MB / 0.7012 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 0.0008307/0.7395, allocations: 459.1 kB / 0.8799 GB, free: 15.28 MB / 0.7012 GB Notification: Performance of pre-optimization done (n=78): time 2.685e-06/0.7395, allocations: 0 / 0.8799 GB, free: 15.28 MB / 0.7012 GB Notification: Performance of matching and sorting (n=78): time 0.002697/0.7422, allocations: 1.144 MB / 0.881 GB, free: 14.11 MB / 0.7012 GB Notification: Performance of inlineWhenForInitialization (initialization): time 0.0001009/0.7423, allocations: 188.6 kB / 0.8812 GB, free: 13.88 MB / 0.7012 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.0008287/0.7431, allocations: 0.6568 MB / 0.8818 GB, free: 13.21 MB / 0.7012 GB Notification: Performance of collectPreVariables (initialization): time 6.296e-05/0.7432, allocations: 41.69 kB / 0.8819 GB, free: 13.17 MB / 0.7012 GB Notification: Performance of collectInitialEqns (initialization): time 0.0004314/0.7437, allocations: 495.7 kB / 0.8824 GB, free: 12.68 MB / 0.7012 GB Notification: Performance of collectInitialBindings (initialization): time 0.000213/0.7439, allocations: 264.1 kB / 0.8826 GB, free: 12.41 MB / 0.7012 GB Notification: Performance of simplifyInitialFunctions (initialization): time 4.204e-05/0.7439, allocations: 16 kB / 0.8826 GB, free: 12.4 MB / 0.7012 GB Notification: Performance of setup shared object (initialization): time 0.0001791/0.7441, allocations: 394.7 kB / 0.883 GB, free: 12 MB / 0.7012 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.0004678/0.7446, allocations: 257.9 kB / 0.8832 GB, free: 11.75 MB / 0.7012 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.0006474/0.7452, allocations: 351.1 kB / 0.8836 GB, free: 11.39 MB / 0.7012 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.0005529/0.7458, allocations: 307 kB / 0.8839 GB, free: 11.09 MB / 0.7012 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 3.486e-06/0.7458, allocations: 7.938 kB / 0.8839 GB, free: 11.09 MB / 0.7012 GB Notification: Performance of matching and sorting (n=94) (initialization): time 0.001711/0.7475, allocations: 0.8409 MB / 0.8847 GB, free: 10.24 MB / 0.7012 GB Notification: Performance of prepare postOptimizeDAE: time 2.128e-05/0.7476, allocations: 4 kB / 0.8847 GB, free: 10.23 MB / 0.7012 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 8.405e-06/0.7476, allocations: 0 / 0.8847 GB, free: 10.23 MB / 0.7012 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.0005417/0.7481, allocations: 84.88 kB / 0.8848 GB, free: 10.15 MB / 0.7012 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0006356/0.7488, allocations: 163.7 kB / 0.8849 GB, free: 9.988 MB / 0.7012 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.002209/0.751, allocations: 1.516 MB / 0.8864 GB, free: 8.328 MB / 0.7012 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.0007271/0.7518, allocations: 104.7 kB / 0.8865 GB, free: 8.227 MB / 0.7012 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 7.482e-05/0.7518, allocations: 40.03 kB / 0.8866 GB, free: 8.188 MB / 0.7012 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 4 * Number of states: 0 () * Number of discrete variables: 8 ($whenCondition2,$whenCondition1,$PRE.weaDat.conTimMin.tNext,weaDat.conTimMin.tNext,$PRE.weaDat.conTim.tNext,weaDat.conTim.tNext,weaDat.conTimMin.canRepeatWeatherFile,weaDat.conTim.canRepeatWeatherFile) * Number of discrete states: 0 () * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for initialization (92): * Single equations (assignments): 91 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 1 {1 2} Notification: Performance of prepare postOptimizeDAE: time 0.0005124/0.7524, allocations: 273.7 kB / 0.8868 GB, free: 7.91 MB / 0.7012 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0001255/0.7525, allocations: 82.97 kB / 0.8869 GB, free: 7.828 MB / 0.7012 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.002185/0.7547, allocations: 1.038 MB / 0.8879 GB, free: 6.773 MB / 0.7012 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 1.082e-05/0.7547, allocations: 8 kB / 0.8879 GB, free: 6.766 MB / 0.7012 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 3.086e-06/0.7547, allocations: 0 / 0.8879 GB, free: 6.766 MB / 0.7012 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 2.321e-05/0.7547, allocations: 3.984 kB / 0.8879 GB, free: 6.762 MB / 0.7012 GB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.001227/0.756, allocations: 0.9738 MB / 0.8889 GB, free: 5.738 MB / 0.7012 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 8.887e-06/0.756, allocations: 0 / 0.8889 GB, free: 5.738 MB / 0.7012 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0005834/0.7566, allocations: 155.7 kB / 0.889 GB, free: 5.586 MB / 0.7012 GB Notification: Performance of postOpt tearingSystem (simulation): time 0.0004598/0.7571, allocations: 88.86 kB / 0.8891 GB, free: 5.496 MB / 0.7012 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 5.654e-05/0.7571, allocations: 23.92 kB / 0.8891 GB, free: 5.473 MB / 0.7012 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.001742/0.7589, allocations: 1.54 MB / 0.8906 GB, free: 3.793 MB / 0.7012 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 3.737e-06/0.7589, allocations: 8.047 kB / 0.8906 GB, free: 3.785 MB / 0.7012 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.00181/0.7607, allocations: 0.8926 MB / 0.8915 GB, free: 2.875 MB / 0.7012 GB Notification: Performance of postOpt removeConstants (simulation): time 0.000449/0.7612, allocations: 271.7 kB / 0.8918 GB, free: 2.59 MB / 0.7012 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0001607/0.7613, allocations: 20 kB / 0.8918 GB, free: 2.57 MB / 0.7012 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.0005774/0.7619, allocations: 70.58 kB / 0.8919 GB, free: 2.504 MB / 0.7012 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0001394/0.7621, allocations: 60.91 kB / 0.8919 GB, free: 2.445 MB / 0.7012 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 6.755e-05/0.7622, allocations: 31.98 kB / 0.892 GB, free: 2.414 MB / 0.7012 GB Notification: Performance of sorting global known variables: time 0.0007961/0.763, allocations: 475 kB / 0.8924 GB, free: 1.953 MB / 0.7012 GB Notification: Performance of sort global known variables: time 2.31e-07/0.763, allocations: 0 / 0.8924 GB, free: 1.953 MB / 0.7012 GB Notification: Performance of remove unused functions: time 0.001097/0.7641, allocations: 326.7 kB / 0.8927 GB, free: 1.633 MB / 0.7012 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 1 * Number of states: 0 () * Number of discrete variables: 4 ($whenCondition2,$whenCondition1,weaDat.conTimMin.tNext,weaDat.conTim.tNext) * Number of discrete states: 2 (weaDat.conTimMin.tNext,weaDat.conTim.tNext) * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for simulation (89): * Single equations (assignments): 86 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 2 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 1 {1 3} Notification: Performance of Backend phase and start with SimCode phase: time 0.001413/0.7655, allocations: 0.56 MB / 0.8933 GB, free: 1.238 MB / 0.7012 GB Notification: Performance of simCode: created initialization part: time 0.001692/0.7672, allocations: 0.8038 MB / 0.894 GB, free: 428 kB / 0.7012 GB Notification: Performance of simCode: created event and clocks part: time 5.781e-06/0.7672, allocations: 8.188 kB / 0.8941 GB, free: 420 kB / 0.7012 GB Notification: Performance of simCode: created simulation system equations: time 0.0008835/0.7681, allocations: 0.4964 MB / 0.8945 GB, free: 15.9 MB / 0.7169 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.001534/0.7697, allocations: 255.1 kB / 0.8948 GB, free: 15.66 MB / 0.7169 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.004805/0.7745, allocations: 2.437 MB / 0.8972 GB, free: 13.2 MB / 0.7169 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.0008268/0.7753, allocations: 1.074 MB / 0.8982 GB, free: 12.1 MB / 0.7169 GB Notification: Performance of simCode: alias equations: time 0.0009545/0.7763, allocations: 262.7 kB / 0.8985 GB, free: 11.84 MB / 0.7169 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0002816/0.7766, allocations: 103.4 kB / 0.8986 GB, free: 11.74 MB / 0.7169 GB Notification: Performance of SimCode: time 9.41e-07/0.7766, allocations: 0 / 0.8986 GB, free: 11.74 MB / 0.7169 GB Notification: Performance of Templates: time 0.448/1.225, allocations: 13.07 MB / 0.9113 GB, free: 178.7 MB / 0.7169 GB make -j1 -f Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic.makefile Environment - environmentSimulation: (rm -f Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic.pipe ; mkfifo Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic.pipe ; head -c 1048576 < Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic.pipe >> ../files/Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic.sim & ./Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic -abortSlowSimulation -alarm=480 -lv LOG_STATS > Buildings_maint.7.0.x_Buildings.BoundaryConditions.SolarIrradiation.Examples.DiffuseIsotropic.pipe 2>&1) Environment - environmentSimulation: