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.YY.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.YY,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY") translateModel(Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY") Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.001192/0.001192, 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 0.00902/0.009021, allocations: 168.9 kB / 16.26 MB, free: 6.648 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo): time 1.615/1.615, allocations: 205.4 MB / 222.5 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 1.506/1.506, allocations: 252 MB / 0.5105 GB, free: 4.645 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 0.0005237/0.0005237, allocations: 12 kB / 0.6249 GB, free: 0.6719 MB / 0.5137 GB Notification: Performance of FrontEnd - Absyn->SCode: time 0.5727/0.5732, allocations: 106.3 MB / 0.7288 GB, free: 11.23 MB / 0.545 GB Notification: Performance of NFInst.instantiate(Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY): time 0.02196/0.5953, allocations: 18.77 MB / 0.7471 GB, free: 8.391 MB / 0.5606 GB Notification: Performance of NFInst.instExpressions: time 0.01437/0.6097, allocations: 7.196 MB / 0.7541 GB, free: 1.172 MB / 0.5606 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.002329/0.6121, allocations: 47.88 kB / 0.7542 GB, free: 1.125 MB / 0.5606 GB Notification: Performance of NFTyping.typeComponents: time 0.001683/0.6138, allocations: 421 kB / 0.7546 GB, free: 0.7109 MB / 0.5606 GB Notification: Performance of NFTyping.typeBindings: time 0.004394/0.6182, allocations: 1.421 MB / 0.756 GB, free: 15.29 MB / 0.5762 GB Notification: Performance of NFTyping.typeClassSections: time 0.003348/0.6216, allocations: 1.033 MB / 0.757 GB, free: 14.25 MB / 0.5762 GB Notification: Performance of NFFlatten.flatten: time 0.01/0.6316, allocations: 9.205 MB / 0.766 GB, free: 5.027 MB / 0.5762 GB Notification: Performance of NFFlatten.resolveConnections: time 0.01609/0.6477, allocations: 10.22 MB / 0.7759 GB, free: 10.69 MB / 0.5919 GB Notification: Performance of NFEvalConstants.evaluate: time 0.003711/0.6514, allocations: 1.786 MB / 0.7777 GB, free: 8.898 MB / 0.5919 GB Notification: Performance of NFSimplifyModel.simplify: time 0.004834/0.6563, allocations: 2.851 MB / 0.7805 GB, free: 6.039 MB / 0.5919 GB Notification: Performance of NFPackage.collectConstants: time 0.0012/0.6575, allocations: 256 kB / 0.7807 GB, free: 5.789 MB / 0.5919 GB Notification: Performance of NFFlatten.collectFunctions: time 0.003698/0.6612, allocations: 1.197 MB / 0.7819 GB, free: 4.59 MB / 0.5919 GB Notification: Performance of NFScalarize.scalarize: time 0.003867/0.6651, allocations: 2.042 MB / 0.7839 GB, free: 2.543 MB / 0.5919 GB Notification: Performance of NFVerifyModel.verify: time 0.004735/0.6699, allocations: 1.934 MB / 0.7858 GB, free: 0.5938 MB / 0.5919 GB Notification: Performance of NFConvertDAE.convert: time 0.01126/0.6812, allocations: 8.134 MB / 0.7937 GB, free: 8.434 MB / 0.6075 GB Notification: Performance of FrontEnd - DAE generated: time 6.542e-06/0.6812, allocations: 0 / 0.7937 GB, free: 8.434 MB / 0.6075 GB Notification: Performance of FrontEnd: time 2.084e-06/0.6812, allocations: 0 / 0.7937 GB, free: 8.434 MB / 0.6075 GB Notification: Performance of Transformations before backend: time 0.0003206/0.6816, allocations: 4 kB / 0.7937 GB, free: 8.43 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: 1083 * Number of variables: 1083 Notification: Performance of Generate backend data structure: time 0.01107/0.6926, allocations: 3.263 MB / 0.7969 GB, free: 5.105 MB / 0.6075 GB Notification: Performance of prepare preOptimizeDAE: time 4.493e-05/0.6927, allocations: 12.03 kB / 0.7969 GB, free: 5.094 MB / 0.6075 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.01371/0.7064, allocations: 2.38 MB / 0.7992 GB, free: 2.707 MB / 0.6075 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.005649/0.7121, allocations: 2.288 MB / 0.8015 GB, free: 384 kB / 0.6075 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0003296/0.7125, allocations: 300.2 kB / 0.8017 GB, free: 84 kB / 0.6075 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.001532/0.714, allocations: 387.9 kB / 0.8021 GB, free: 15.7 MB / 0.6231 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.01968/0.7337, allocations: 7.634 MB / 0.8096 GB, free: 7.949 MB / 0.6231 GB Notification: Performance of preOpt findStateOrder (simulation): time 0.0001628/0.7339, allocations: 7.938 kB / 0.8096 GB, free: 7.941 MB / 0.6231 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.001228/0.7352, allocations: 163.9 kB / 0.8097 GB, free: 7.781 MB / 0.6231 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 0.0005208/0.7357, allocations: 346.7 kB / 0.8101 GB, free: 7.441 MB / 0.6231 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.01747/0.7532, allocations: 7.249 MB / 0.8171 GB, free: 192 kB / 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 0.03844/0.7917, allocations: 28.49 MB / 0.845 GB, free: 1.316 MB / 0.6544 GB Notification: Performance of preOpt comSubExp (simulation): time 0.007356/0.7991, allocations: 3.667 MB / 0.8485 GB, free: 13.49 MB / 0.67 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.004826/0.8039, allocations: 1.999 MB / 0.8505 GB, free: 11.47 MB / 0.67 GB Notification: Performance of preOpt evalFunc (simulation): time 0.0002238/0.8042, allocations: 130.3 kB / 0.8506 GB, free: 11.32 MB / 0.67 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 5.995e-05/0.8042, allocations: 55.88 kB / 0.8507 GB, free: 11.26 MB / 0.67 GB Notification: Performance of pre-optimization done (n=176): time 3.777e-06/0.8043, allocations: 0 / 0.8507 GB, free: 11.26 MB / 0.67 GB Notification: Performance of matching and sorting (n=221): time 0.08224/0.8865, allocations: 24.74 MB / 0.8748 GB, free: 2.414 MB / 0.6856 GB Notification: Performance of inlineWhenForInitialization (initialization): time 0.0001389/0.8867, allocations: 231.6 kB / 0.8751 GB, free: 2.141 MB / 0.6856 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.002517/0.8892, allocations: 1.598 MB / 0.8766 GB, free: 0.5273 MB / 0.6856 GB Notification: Performance of collectPreVariables (initialization): time 0.0005337/0.8897, allocations: 61.7 kB / 0.8767 GB, free: 472 kB / 0.6856 GB Notification: Performance of collectInitialEqns (initialization): time 0.001296/0.8911, allocations: 1.724 MB / 0.8784 GB, free: 14.71 MB / 0.7012 GB Notification: Performance of collectInitialBindings (initialization): time 0.0009095/0.892, allocations: 0.7587 MB / 0.8791 GB, free: 13.94 MB / 0.7012 GB Notification: Performance of simplifyInitialFunctions (initialization): time 0.000414/0.8924, allocations: 252.2 kB / 0.8793 GB, free: 13.69 MB / 0.7012 GB Notification: Performance of setup shared object (initialization): time 9.3e-05/0.8925, allocations: 301.1 kB / 0.8796 GB, free: 13.39 MB / 0.7012 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.005655/0.8982, allocations: 2.461 MB / 0.882 GB, free: 10.93 MB / 0.7012 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.00652/0.9047, allocations: 3.574 MB / 0.8855 GB, free: 6.852 MB / 0.7012 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.01238/0.9171, allocations: 6.178 MB / 0.8916 GB, free: 188 kB / 0.7012 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 4.059e-05/0.9172, allocations: 8 kB / 0.8916 GB, free: 180 kB / 0.7012 GB Notification: Performance of matching and sorting (n=400) (initialization): time 0.02868/0.9459, allocations: 10.03 MB / 0.9014 GB, free: 6.117 MB / 0.7169 GB Notification: Performance of prepare postOptimizeDAE: time 0.0009154/0.9468, allocations: 1.122 MB / 0.9024 GB, free: 4.504 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 4.562e-05/0.9469, allocations: 36 kB / 0.9025 GB, free: 4.469 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.5003/1.447, allocations: 5.459 MB / 0.9078 GB, free: 157.8 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.005017/1.452, allocations: 1.029 MB / 0.9088 GB, free: 157.8 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.0354/1.488, allocations: 19.34 MB / 0.9277 GB, free: 150.3 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.00438/1.492, allocations: 0.5786 MB / 0.9283 GB, free: 150.3 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0004146/1.493, allocations: 164.2 kB / 0.9284 GB, free: 150.2 MB / 0.7169 GB Notification: Performance of prepare postOptimizeDAE: time 1.167e-05/1.493, allocations: 4.594 kB / 0.9284 GB, free: 150.2 MB / 0.7169 GB Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.01966/1.512, allocations: 8.313 MB / 0.9365 GB, free: 148 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 0.0001252/1.512, allocations: 38.08 kB / 0.9366 GB, free: 148 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.01248/1.525, allocations: 3.437 MB / 0.9399 GB, free: 146.3 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.004509/1.529, allocations: 1.151 MB / 0.9411 GB, free: 145.2 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.01555/1.545, allocations: 10.61 MB / 0.9514 GB, free: 134.5 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.004153/1.549, allocations: 0.5456 MB / 0.952 GB, free: 134 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0003431/1.55, allocations: 160 kB / 0.9521 GB, free: 133.8 MB / 0.7169 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 159 * 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 (330): * Single equations (assignments): 328 * 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 {(6,30,100.0%)} * Non-linear torn systems (#iteration vars, #inner vars): 1 system {(6,30)} Notification: Performance of prepare postOptimizeDAE: time 0.00266/1.552, allocations: 1.697 MB / 0.9538 GB, free: 132.1 MB / 0.7169 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0005305/1.553, allocations: 195.7 kB / 0.954 GB, free: 132 MB / 0.7169 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.02143/1.574, allocations: 8.783 MB / 0.9625 GB, free: 123.2 MB / 0.7169 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 2.956e-05/1.574, allocations: 24 kB / 0.9626 GB, free: 123.2 MB / 0.7169 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 1.495e-05/1.574, allocations: 11.98 kB / 0.9626 GB, free: 123.2 MB / 0.7169 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 4.531e-05/1.574, allocations: 7.969 kB / 0.9626 GB, free: 123.2 MB / 0.7169 GB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.02801/1.602, allocations: 14.61 MB / 0.9768 GB, free: 108.4 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 1.915e-05/1.602, allocations: 8 kB / 0.9768 GB, free: 108.4 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.003063/1.606, allocations: 0.7138 MB / 0.9775 GB, free: 107.7 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (simulation): time 0.01796/1.624, allocations: 5.133 MB / 0.9826 GB, free: 102.6 MB / 0.7169 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 0.0004604/1.624, allocations: 71.94 kB / 0.9826 GB, free: 102.5 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.02607/1.65, allocations: 18.22 MB / 1 GB, free: 84.03 MB / 0.7169 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 7.113e-06/1.65, allocations: 11.94 kB / 1 GB, free: 84.02 MB / 0.7169 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.02143/1.672, allocations: 8.862 MB / 1.009 GB, free: 75.04 MB / 0.7169 GB Notification: Performance of postOpt removeConstants (simulation): time 0.001515/1.673, allocations: 0.6569 MB / 1.01 GB, free: 74.36 MB / 0.7169 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0003311/1.674, allocations: 48 kB / 1.01 GB, free: 74.31 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.003231/1.677, allocations: 0.4953 MB / 1.01 GB, free: 73.82 MB / 0.7169 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0006274/1.677, allocations: 189.5 kB / 1.01 GB, free: 73.63 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 0.0001725/1.678, allocations: 79.95 kB / 1.011 GB, free: 73.55 MB / 0.7169 GB Notification: Performance of sorting global known variables: time 0.001203/1.679, allocations: 1.058 MB / 1.012 GB, free: 72.49 MB / 0.7169 GB Notification: Performance of sort global known variables: time 1.4e-07/1.679, allocations: 0 / 1.012 GB, free: 72.49 MB / 0.7169 GB Notification: Performance of remove unused functions: time 0.004962/1.684, allocations: 1.715 MB / 1.013 GB, free: 70.78 MB / 0.7169 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 34 * 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 (154): * Single equations (assignments): 152 * 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 {(6,30,100.0%)} * Non-linear torn systems (#iteration vars, #inner vars): 1 system {(6,30)} Notification: Performance of Backend phase and start with SimCode phase: time 0.0003529/1.684, allocations: 175.8 kB / 1.013 GB, free: 70.6 MB / 0.7169 GB Notification: Performance of simCode: created initialization part: time 0.0243/1.708, allocations: 10.87 MB / 1.024 GB, free: 59.7 MB / 0.7169 GB Notification: Performance of simCode: created event and clocks part: time 1.196e-05/1.708, allocations: 0 / 1.024 GB, free: 59.7 MB / 0.7169 GB Notification: Performance of simCode: created simulation system equations: time 0.009502/1.718, allocations: 3.83 MB / 1.028 GB, free: 55.85 MB / 0.7169 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.003585/1.722, allocations: 261.4 kB / 1.028 GB, free: 55.61 MB / 0.7169 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.02265/1.744, allocations: 11.12 MB / 1.039 GB, free: 44.36 MB / 0.7169 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.002466/1.747, allocations: 2.903 MB / 1.042 GB, free: 41.42 MB / 0.7169 GB Notification: Performance of simCode: alias equations: time 0.004863/1.752, allocations: 1.676 MB / 1.043 GB, free: 39.74 MB / 0.7169 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0006023/1.752, allocations: 167.3 kB / 1.043 GB, free: 39.57 MB / 0.7169 GB Notification: Performance of SimCode: time 5.71e-07/1.752, allocations: 3.938 kB / 1.043 GB, free: 39.57 MB / 0.7169 GB Notification: Performance of Templates: time 0.08747/1.84, allocations: 62.08 MB / 1.104 GB, free: 9.645 MB / 0.7481 GB make -j1 -f Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY.makefile Environment - environmentSimulation: (rm -f Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY.pipe ; mkfifo Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY.pipe ; head -c 1048576 < Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY.pipe >> ../files/Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY.sim & ./Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY -abortSlowSimulation -alarm=480 -lv LOG_STATS > Buildings_maint.7.0.x_Buildings.Electrical.AC.ThreePhasesUnbalanced.Validation.IEEETests.Test4NodesFeeder.BalancedStepUp.YY.pipe 2>&1) Environment - environmentSimulation: