Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY.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.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY") translateModel(Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY") Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.001012/0.001012, allocations: 91.84 kB / 15.36 MB, free: 0.7383 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.007237/0.007238, allocations: 169.6 kB / 16.26 MB, free: 6.613 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo): time 1.671/1.671, allocations: 205.4 MB / 222.4 MB, free: 5.566 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 1.584/1.584, allocations: 252 MB / 0.5105 GB, free: 4.656 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 0.0005119/0.0005119, allocations: 12 kB / 0.6249 GB, free: 0.7109 MB / 0.5137 GB Notification: Performance of FrontEnd - Absyn->SCode: time 0.523/0.5235, allocations: 106.3 MB / 0.7288 GB, free: 11.28 MB / 0.545 GB Notification: Performance of NFInst.instantiate(Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY): time 0.0204/0.544, allocations: 17.45 MB / 0.7458 GB, free: 9.766 MB / 0.5606 GB Notification: Performance of NFInst.instExpressions: time 0.0116/0.5556, allocations: 6.748 MB / 0.7524 GB, free: 2.996 MB / 0.5606 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.00162/0.5573, allocations: 43.88 kB / 0.7524 GB, free: 2.953 MB / 0.5606 GB Notification: Performance of NFTyping.typeComponents: time 0.001103/0.5584, allocations: 389.3 kB / 0.7528 GB, free: 2.57 MB / 0.5606 GB Notification: Performance of NFTyping.typeBindings: time 0.003699/0.5621, allocations: 1.347 MB / 0.7541 GB, free: 1.219 MB / 0.5606 GB Notification: Performance of NFTyping.typeClassSections: time 0.00298/0.5651, allocations: 1.006 MB / 0.7551 GB, free: 220 kB / 0.5606 GB Notification: Performance of NFFlatten.flatten: time 0.01052/0.5757, allocations: 8.76 MB / 0.7636 GB, free: 7.438 MB / 0.5762 GB Notification: Performance of NFFlatten.resolveConnections: time 0.01414/0.5898, allocations: 8.846 MB / 0.7723 GB, free: 14.49 MB / 0.5919 GB Notification: Performance of NFEvalConstants.evaluate: time 0.003666/0.5935, allocations: 1.697 MB / 0.7739 GB, free: 12.79 MB / 0.5919 GB Notification: Performance of NFSimplifyModel.simplify: time 0.004912/0.5985, allocations: 2.734 MB / 0.7766 GB, free: 10.05 MB / 0.5919 GB Notification: Performance of NFPackage.collectConstants: time 0.0008949/0.5994, allocations: 244 kB / 0.7768 GB, free: 9.809 MB / 0.5919 GB Notification: Performance of NFFlatten.collectFunctions: time 0.002648/0.6021, allocations: 1.147 MB / 0.778 GB, free: 8.66 MB / 0.5919 GB Notification: Performance of NFScalarize.scalarize: time 0.002284/0.6043, allocations: 1.937 MB / 0.7799 GB, free: 6.719 MB / 0.5919 GB Notification: Performance of NFVerifyModel.verify: time 0.002755/0.6071, allocations: 1.844 MB / 0.7817 GB, free: 4.859 MB / 0.5919 GB Notification: Performance of NFConvertDAE.convert: time 0.009035/0.6162, allocations: 7.691 MB / 0.7892 GB, free: 13.14 MB / 0.6075 GB Notification: Performance of FrontEnd - DAE generated: time 4.558e-06/0.6162, allocations: 0 / 0.7892 GB, free: 13.14 MB / 0.6075 GB Notification: Performance of FrontEnd: time 3.216e-06/0.6162, allocations: 0 / 0.7892 GB, free: 13.14 MB / 0.6075 GB Notification: Performance of Transformations before backend: time 0.0002112/0.6164, allocations: 0 / 0.7892 GB, free: 13.14 MB / 0.6075 GB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 1023 * Number of variables: 1023 Notification: Performance of Generate backend data structure: time 0.00772/0.6242, allocations: 3.156 MB / 0.7923 GB, free: 9.926 MB / 0.6075 GB Notification: Performance of prepare preOptimizeDAE: time 4.451e-05/0.6242, allocations: 11.97 kB / 0.7923 GB, free: 9.914 MB / 0.6075 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.01241/0.6366, allocations: 2.349 MB / 0.7946 GB, free: 7.559 MB / 0.6075 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.004618/0.6413, allocations: 2.206 MB / 0.7967 GB, free: 5.309 MB / 0.6075 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0002169/0.6415, allocations: 275.8 kB / 0.797 GB, free: 5.039 MB / 0.6075 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0009424/0.6425, allocations: 363.9 kB / 0.7973 GB, free: 4.684 MB / 0.6075 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.01492/0.6574, allocations: 7.33 MB / 0.8045 GB, free: 13.23 MB / 0.6231 GB Notification: Performance of preOpt findStateOrder (simulation): time 7.583e-05/0.6575, allocations: 3.938 kB / 0.8045 GB, free: 13.23 MB / 0.6231 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0004388/0.658, allocations: 152 kB / 0.8046 GB, free: 13.08 MB / 0.6231 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 0.0004721/0.6585, allocations: 338.3 kB / 0.805 GB, free: 12.75 MB / 0.6231 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.0168/0.6753, allocations: 7.126 MB / 0.8119 GB, free: 5.605 MB / 0.6231 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 0.04368/0.719, allocations: 28.18 MB / 0.8394 GB, free: 7.027 MB / 0.6544 GB Notification: Performance of preOpt comSubExp (simulation): time 0.008664/0.7277, allocations: 4.182 MB / 0.8435 GB, free: 2.625 MB / 0.6544 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.005913/0.7337, allocations: 2.323 MB / 0.8458 GB, free: 292 kB / 0.6544 GB Notification: Performance of preOpt evalFunc (simulation): time 0.0003813/0.7341, allocations: 139 kB / 0.8459 GB, free: 136 kB / 0.6544 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 5.785e-05/0.7342, allocations: 60.5 kB / 0.846 GB, free: 64 kB / 0.6544 GB Notification: Performance of pre-optimization done (n=198): time 4.729e-06/0.7342, allocations: 0 / 0.846 GB, free: 64 kB / 0.6544 GB Notification: Performance of matching and sorting (n=257): time 0.1113/0.8455, allocations: 30.43 MB / 0.8757 GB, free: 1.551 MB / 0.6856 GB Notification: Performance of inlineWhenForInitialization (initialization): time 0.0001713/0.8457, allocations: 239.6 kB / 0.8759 GB, free: 1.27 MB / 0.6856 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.002397/0.8481, allocations: 1.42 MB / 0.8773 GB, free: 15.84 MB / 0.7012 GB Notification: Performance of collectPreVariables (initialization): time 0.0005248/0.8486, allocations: 73.7 kB / 0.8774 GB, free: 15.76 MB / 0.7012 GB Notification: Performance of collectInitialEqns (initialization): time 0.001014/0.8497, allocations: 1.543 MB / 0.8789 GB, free: 14.2 MB / 0.7012 GB Notification: Performance of collectInitialBindings (initialization): time 0.001094/0.8508, allocations: 0.8742 MB / 0.8797 GB, free: 13.31 MB / 0.7012 GB Notification: Performance of simplifyInitialFunctions (initialization): time 0.000585/0.8514, allocations: 248.2 kB / 0.88 GB, free: 13.06 MB / 0.7012 GB Notification: Performance of setup shared object (initialization): time 9.226e-05/0.8515, allocations: 301.1 kB / 0.8803 GB, free: 12.76 MB / 0.7012 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.005891/0.8574, allocations: 2.539 MB / 0.8827 GB, free: 10.22 MB / 0.7012 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.006651/0.864, allocations: 3.439 MB / 0.8861 GB, free: 6.398 MB / 0.7012 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.01228/0.8764, allocations: 6.137 MB / 0.8921 GB, free: 15.86 MB / 0.7169 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 4.983e-05/0.8764, allocations: 8 kB / 0.8921 GB, free: 15.85 MB / 0.7169 GB Notification: Performance of matching and sorting (n=398) (initialization): time 0.03034/0.9068, allocations: 10.27 MB / 0.9021 GB, free: 5.512 MB / 0.7169 GB Notification: Performance of prepare postOptimizeDAE: time 0.0008842/0.9077, allocations: 0.8759 MB / 0.903 GB, free: 4.254 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 6.935e-05/0.9078, allocations: 28 kB / 0.903 GB, free: 4.227 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.6278/1.536, allocations: 5.664 MB / 0.9085 GB, free: 159.6 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.007519/1.543, allocations: 0.9838 MB / 0.9095 GB, free: 159.6 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.04287/1.586, allocations: 21.57 MB / 0.9306 GB, free: 151.1 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.004346/1.591, allocations: 0.5522 MB / 0.9311 GB, free: 151.1 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0006968/1.591, allocations: 154.5 kB / 0.9313 GB, free: 151 MB / 0.7169 GB Notification: Performance of prepare postOptimizeDAE: time 1.275e-05/1.591, allocations: 7.438 kB / 0.9313 GB, free: 151 MB / 0.7169 GB Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.02054/1.612, allocations: 8.443 MB / 0.9395 GB, free: 148.1 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 8.481e-05/1.612, allocations: 27.06 kB / 0.9395 GB, free: 148.1 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.01308/1.625, allocations: 3.535 MB / 0.943 GB, free: 144.7 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.005172/1.63, allocations: 1.131 MB / 0.9441 GB, free: 143.6 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.01816/1.648, allocations: 11.79 MB / 0.9556 GB, free: 131.8 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.004132/1.653, allocations: 0.5241 MB / 0.9561 GB, free: 131.3 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0006008/1.653, allocations: 148 kB / 0.9563 GB, free: 131.1 MB / 0.7169 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 121 * 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 (304): * Single equations (assignments): 302 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (not torn): 0 * Torn equation systems: 2 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems (#iteration vars, #inner vars, density): 1 system {(6,42,100.0%)} * Non-linear torn systems (#iteration vars, #inner vars): 1 system {(6,42)} Notification: Performance of prepare postOptimizeDAE: time 0.003152/1.656, allocations: 1.616 MB / 0.9578 GB, free: 129.5 MB / 0.7169 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0007551/1.657, allocations: 195 kB / 0.958 GB, free: 129.4 MB / 0.7169 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.02466/1.682, allocations: 9.835 MB / 0.9676 GB, free: 119.5 MB / 0.7169 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 3.895e-05/1.682, allocations: 24 kB / 0.9676 GB, free: 119.5 MB / 0.7169 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 2.642e-05/1.682, allocations: 12 kB / 0.9677 GB, free: 119.5 MB / 0.7169 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 4.843e-05/1.682, allocations: 19.94 kB / 0.9677 GB, free: 119.5 MB / 0.7169 GB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.03298/1.715, allocations: 15.19 MB / 0.9825 GB, free: 104.1 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 5.063e-05/1.715, allocations: 8 kB / 0.9825 GB, free: 104.1 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.003242/1.718, allocations: 0.7338 MB / 0.9832 GB, free: 103.4 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (simulation): time 0.01954/1.738, allocations: 5.334 MB / 0.9884 GB, free: 98.03 MB / 0.7169 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 0.0005921/1.739, allocations: 79.89 kB / 0.9885 GB, free: 97.95 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.03328/1.772, allocations: 20.44 MB / 1.008 GB, free: 77.25 MB / 0.7169 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 8.035e-06/1.772, allocations: 15.94 kB / 1.008 GB, free: 77.23 MB / 0.7169 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.02527/1.797, allocations: 9.375 MB / 1.018 GB, free: 67.67 MB / 0.7169 GB Notification: Performance of postOpt removeConstants (simulation): time 0.00307/1.8, allocations: 0.6885 MB / 1.018 GB, free: 66.96 MB / 0.7169 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.00135/1.802, allocations: 55.98 kB / 1.018 GB, free: 66.91 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.004803/1.807, allocations: 0.5031 MB / 1.019 GB, free: 66.4 MB / 0.7169 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.001353/1.808, allocations: 226.3 kB / 1.019 GB, free: 66.18 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 0.0005022/1.809, allocations: 87.95 kB / 1.019 GB, free: 66.09 MB / 0.7169 GB Notification: Performance of sorting global known variables: time 0.001915/1.81, allocations: 0.9964 MB / 1.02 GB, free: 65.09 MB / 0.7169 GB Notification: Performance of sort global known variables: time 2.21e-07/1.81, allocations: 0 / 1.02 GB, free: 65.09 MB / 0.7169 GB Notification: Performance of remove unused functions: time 0.00759/1.818, allocations: 1.746 MB / 1.022 GB, free: 63.35 MB / 0.7169 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 40 * 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 simulation (162): * Single equations (assignments): 160 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (not torn): 0 * Torn equation systems: 2 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems (#iteration vars, #inner vars, density): 1 system {(6,42,100.0%)} * Non-linear torn systems (#iteration vars, #inner vars): 1 system {(6,42)} Notification: Performance of Backend phase and start with SimCode phase: time 0.0007355/1.819, allocations: 178 kB / 1.022 GB, free: 63.17 MB / 0.7169 GB Notification: Performance of simCode: created initialization part: time 0.02813/1.847, allocations: 11.33 MB / 1.033 GB, free: 51.79 MB / 0.7169 GB Notification: Performance of simCode: created event and clocks part: time 2.245e-05/1.847, allocations: 4 kB / 1.033 GB, free: 51.78 MB / 0.7169 GB Notification: Performance of simCode: created simulation system equations: time 0.01065/1.858, allocations: 4.131 MB / 1.037 GB, free: 47.62 MB / 0.7169 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.004726/1.863, allocations: 263 kB / 1.037 GB, free: 47.38 MB / 0.7169 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.03143/1.894, allocations: 12.38 MB / 1.049 GB, free: 34.85 MB / 0.7169 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.003931/1.898, allocations: 2.847 MB / 1.052 GB, free: 31.97 MB / 0.7169 GB Notification: Performance of simCode: alias equations: time 0.005613/1.904, allocations: 1.66 MB / 1.054 GB, free: 30.3 MB / 0.7169 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0007988/1.904, allocations: 171.3 kB / 1.054 GB, free: 30.14 MB / 0.7169 GB Notification: Performance of SimCode: time 1.132e-06/1.904, allocations: 0 / 1.054 GB, free: 30.14 MB / 0.7169 GB Notification: Performance of Templates: time 0.1029/2.007, allocations: 66.11 MB / 1.119 GB, free: 12.21 MB / 0.7637 GB make -j1 -f Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY.makefile Environment - environmentSimulation: (rm -f Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY.pipe ; mkfifo Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY.pipe ; head -c 1048576 < Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY.pipe >> ../files/Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY.sim & ./Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY -abortSlowSimulation -alarm=480 -lv LOG_STATS > Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.DY.pipe 2>&1) Environment - environmentSimulation: