Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine.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 1.6.0+build.1/package.mo", uses=false)
Using package Buildings with version 1.6 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 1.6.0+build.1/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.Fluid.Movers.Examples.ControlledFlowMachine,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine")
translateModel(Buildings.Fluid.Movers.Examples.ControlledFlowMachine,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine")
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.001283/0.001283, allocations: 91.14 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 0.0128/0.0128, allocations: 171.4 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 1.871/1.871, allocations: 205.4 MB / 222.4 MB, free: 5.797 MB / 174.1 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 1.6.0+build.1/package.mo): time 0.6356/0.6356, allocations: 95.63 MB / 366.4 MB, free: 10.29 MB / 302.1 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: Buildings requested package Modelica of version 3.2.1. Modelica 3.2.3 is used instead which states that it is fully compatible without conversion script needed.
Notification: Performance of FrontEnd - loaded program: time 0.0006498/0.0006501, allocations: 12 kB / 447.5 MB, free: 9.02 MB / 382.1 MB
Notification: Performance of FrontEnd - Absyn->SCode: time 0.3568/0.3575, allocations: 70.33 MB / 0.5057 GB, free: 16.46 MB / 382.1 MB
Notification: Performance of NFInst.instantiate(Buildings.Fluid.Movers.Examples.ControlledFlowMachine): time 0.5646/0.9221, allocations: 233.5 MB / 0.7337 GB, free: 5.039 MB / 0.4981 GB
Notification: Performance of NFInst.instExpressions: time 0.04458/0.9667, allocations: 26.52 MB / 0.7596 GB, free: 10.91 MB / 0.5294 GB
Notification: Performance of NFInst.updateImplicitVariability: time 0.009156/0.976, allocations: 162.6 kB / 0.7597 GB, free: 10.75 MB / 0.5294 GB
Notification: Performance of NFTyping.typeComponents: time 0.007373/0.9834, allocations: 1.383 MB / 0.7611 GB, free: 9.363 MB / 0.5294 GB
Notification: Performance of NFTyping.typeBindings: time 0.01366/0.9971, allocations: 3.187 MB / 0.7642 GB, free: 6.164 MB / 0.5294 GB
Notification: Performance of NFTyping.typeClassSections: time 0.01089/1.008, allocations: 3.446 MB / 0.7675 GB, free: 2.738 MB / 0.5294 GB
Notification: Performance of NFFlatten.flatten: time 0.01494/1.023, allocations: 10.19 MB / 0.7775 GB, free: 8.52 MB / 0.545 GB
Notification: Performance of NFFlatten.resolveConnections: time 0.0058/1.029, allocations: 1.968 MB / 0.7794 GB, free: 6.504 MB / 0.545 GB
Notification: Performance of NFEvalConstants.evaluate: time 0.007156/1.036, allocations: 2.307 MB / 0.7817 GB, free: 4.188 MB / 0.545 GB
Notification: Performance of NFSimplifyModel.simplify: time 0.006599/1.043, allocations: 2.801 MB / 0.7844 GB, free: 1.375 MB / 0.545 GB
Notification: Performance of NFPackage.collectConstants: time 0.00144/1.044, allocations: 152 kB / 0.7845 GB, free: 1.227 MB / 0.545 GB
Notification: Performance of NFFlatten.collectFunctions: time 0.008939/1.053, allocations: 2.507 MB / 0.787 GB, free: 14.71 MB / 0.5606 GB
Notification: Performance of NFScalarize.scalarize: time 0.002272/1.055, allocations: 0.6301 MB / 0.7876 GB, free: 14.08 MB / 0.5606 GB
Notification: Performance of NFVerifyModel.verify: time 0.006607/1.062, allocations: 1.669 MB / 0.7892 GB, free: 12.4 MB / 0.5606 GB
Notification: Performance of NFConvertDAE.convert: time 0.01288/1.075, allocations: 5.038 MB / 0.7942 GB, free: 7.34 MB / 0.5606 GB
Notification: Performance of FrontEnd - DAE generated: time 4.789e-06/1.075, allocations: 0 / 0.7942 GB, free: 7.34 MB / 0.5606 GB
Notification: Performance of FrontEnd: time 2.645e-06/1.075, allocations: 0 / 0.7942 GB, free: 7.34 MB / 0.5606 GB
Notification: Performance of Transformations before backend: time 0.000195/1.075, allocations: 4 kB / 0.7942 GB, free: 7.336 MB / 0.5606 GB
Notification: Model statistics after passing the front-end and creating the data structures used by the back-end:
 * Number of equations: 429
 * Number of variables: 429
Notification: Performance of Generate backend data structure: time 0.008513/1.084, allocations: 3.485 MB / 0.7976 GB, free: 3.742 MB / 0.5606 GB
Notification: Performance of prepare preOptimizeDAE: time 5.124e-05/1.084, allocations: 15.98 kB / 0.7976 GB, free: 3.727 MB / 0.5606 GB
Notification: Performance of preOpt normalInlineFunction (simulation): time 0.001589/1.085, allocations: 375.7 kB / 0.7979 GB, free: 3.355 MB / 0.5606 GB
Notification: Performance of preOpt evaluateParameters (simulation): time 0.006757/1.092, allocations: 2.701 MB / 0.8006 GB, free: 0.5859 MB / 0.5606 GB
Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0004188/1.093, allocations: 230.8 kB / 0.8008 GB, free: 356 kB / 0.5606 GB
Notification: Performance of preOpt expandDerOperator (simulation): time 0.00102/1.094, allocations: 208 kB / 0.801 GB, free: 148 kB / 0.5606 GB
Notification: Performance of preOpt clockPartitioning (simulation): time 0.004711/1.098, allocations: 2.361 MB / 0.8033 GB, free: 13.72 MB / 0.5762 GB
Notification: Performance of preOpt findStateOrder (simulation): time 3.333e-05/1.098, allocations: 0 / 0.8033 GB, free: 13.72 MB / 0.5762 GB
Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0002316/1.099, allocations: 75.92 kB / 0.8034 GB, free: 13.64 MB / 0.5762 GB
Notification: Performance of preOpt inlineArrayEqn (simulation): time 3.44e-05/1.099, allocations: 51.98 kB / 0.8034 GB, free: 13.59 MB / 0.5762 GB
Notification: Performance of preOpt removeEqualRHS (simulation): time 0.003229/1.102, allocations: 1.679 MB / 0.8051 GB, free: 11.91 MB / 0.5762 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 0.01343/1.115, allocations: 9.6 MB / 0.8144 GB, free: 1.695 MB / 0.5762 GB
Notification: Performance of preOpt comSubExp (simulation): time 0.004873/1.12, allocations: 1.7 MB / 0.8161 GB, free: 15.98 MB / 0.5919 GB
Notification: Performance of preOpt resolveLoops (simulation): time 0.001017/1.121, allocations: 0.5613 MB / 0.8167 GB, free: 15.42 MB / 0.5919 GB
Notification: Performance of preOpt evalFunc (simulation): time 0.002614/1.124, allocations: 2.934 MB / 0.8195 GB, free: 11.82 MB / 0.5919 GB
Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 0.002269/1.126, allocations: 1.124 MB / 0.8206 GB, free: 10.67 MB / 0.5919 GB
Notification: Performance of pre-optimization done (n=95): time 2.445e-05/1.126, allocations: 0 / 0.8206 GB, free: 10.67 MB / 0.5919 GB
Notification: Performance of matching and sorting (n=95): time 0.01042/1.137, allocations: 3.02 MB / 0.8236 GB, free: 7.57 MB / 0.5919 GB
Notification: Performance of inlineWhenForInitialization (initialization): time 0.0001882/1.137, allocations: 218.6 kB / 0.8238 GB, free: 7.309 MB / 0.5919 GB
Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.006428/1.143, allocations: 2.346 MB / 0.8261 GB, free: 4.949 MB / 0.5919 GB
Notification: Performance of collectPreVariables (initialization): time 0.0007145/1.144, allocations: 69.64 kB / 0.8261 GB, free: 4.875 MB / 0.5919 GB
Notification: Performance of collectInitialEqns (initialization): time 0.00198/1.146, allocations: 1.251 MB / 0.8274 GB, free: 3.609 MB / 0.5919 GB
Notification: Performance of collectInitialBindings (initialization): time 0.0006546/1.147, allocations: 327.2 kB / 0.8277 GB, free: 3.285 MB / 0.5919 GB
Notification: Performance of simplifyInitialFunctions (initialization): time 0.0008094/1.148, allocations: 217.6 kB / 0.8279 GB, free: 3.066 MB / 0.5919 GB
Notification: Performance of setup shared object (initialization): time 0.0001283/1.148, allocations: 309.1 kB / 0.8282 GB, free: 2.762 MB / 0.5919 GB
Notification: Performance of preBalanceInitialSystem (initialization): time 0.004204/1.152, allocations: 2.475 MB / 0.8306 GB, free: 288 kB / 0.5919 GB
Notification: Performance of partitionIndependentBlocks (initialization): time 0.004309/1.156, allocations: 2.82 MB / 0.8333 GB, free: 13.33 MB / 0.6075 GB
Notification: Performance of analyzeInitialSystem (initialization): time 0.00657/1.163, allocations: 4.508 MB / 0.8377 GB, free: 8.672 MB / 0.6075 GB
Notification: Performance of solveInitialSystemEqSystem (initialization): time 1.521e-05/1.163, allocations: 4 kB / 0.8377 GB, free: 8.668 MB / 0.6075 GB
Notification: Performance of matching and sorting (n=258) (initialization): time 0.01377/1.177, allocations: 6.898 MB / 0.8445 GB, free: 1.707 MB / 0.6075 GB
Notification: Performance of prepare postOptimizeDAE: time 0.0007057/1.177, allocations: 0.8213 MB / 0.8453 GB, free: 0.7383 MB / 0.6075 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 3.498e-05/1.178, allocations: 8 kB / 0.8453 GB, free: 0.7305 MB / 0.6075 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.003753/1.181, allocations: 1.697 MB / 0.8469 GB, free: 15.03 MB / 0.6231 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.00106/1.182, allocations: 259.6 kB / 0.8472 GB, free: 14.77 MB / 0.6231 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.002631/1.185, allocations: 2.559 MB / 0.8497 GB, free: 12.14 MB / 0.6231 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.003062/1.188, allocations: 433.3 kB / 0.8501 GB, free: 11.71 MB / 0.6231 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0007818/1.189, allocations: 223.9 kB / 0.8503 GB, free: 11.49 MB / 0.6231 GB
Notification: Performance of prepare postOptimizeDAE: time 1.27e-05/1.189, allocations: 7.938 kB / 0.8503 GB, free: 11.48 MB / 0.6231 GB
Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.0136/1.203, allocations: 7.419 MB / 0.8576 GB, free: 3.988 MB / 0.6231 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 3.334e-05/1.203, allocations: 8 kB / 0.8576 GB, free: 3.98 MB / 0.6231 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.005315/1.208, allocations: 2.5 MB / 0.86 GB, free: 1.469 MB / 0.6231 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001191/1.209, allocations: 247.6 kB / 0.8603 GB, free: 1.227 MB / 0.6231 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.004848/1.214, allocations: 4.168 MB / 0.8643 GB, free: 12.87 MB / 0.6387 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.004103/1.218, allocations: 366.1 kB / 0.8647 GB, free: 12.51 MB / 0.6387 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0009043/1.219, allocations: 207.9 kB / 0.8649 GB, free: 12.31 MB / 0.6387 GB
Notification: Model statistics after passing the back-end for initialization:
 * Number of independent subsystems: 33
 * Number of states: 0 ()
 * Number of discrete variables: 13 (fan4.haveVMax,fan4.haveDPMax,fan4.haveMinimumDecrease,fan4.curve,fan1.haveVMax,fan1.haveDPMax,fan1.haveMinimumDecrease,fan1.curve,y.count,$PRE.y.count,y.T_start,$PRE.y.T_start,$whenCondition1)
 * Number of discrete states: 0 ()
 * Number of clocked states: 0 ()
 * Top-level inputs: 0
Notification: Strong component statistics for initialization (143):
 * Single equations (assignments): 133
 * Array equations: 0
 * Algorithm blocks: 7
 * Record equations: 0
 * When equations: 0
 * If-equations: 0
 * Equation systems (not torn): 0
 * Torn equation systems: 3
 * Mixed (continuous/discrete) equation systems: 0
Notification: Torn system details for strict tearing set:
 * Linear torn systems (#iteration vars, #inner vars, density): 0 systems
 * Non-linear torn systems (#iteration vars, #inner vars): 3 systems
   {(1,4), (1,7), (1,7)}
Notification: Performance of prepare postOptimizeDAE: time 0.002092/1.221, allocations: 0.5873 MB / 0.8654 GB, free: 11.71 MB / 0.6387 GB
Notification: Performance of postOpt lateInlineFunction (simulation): time 0.001051/1.222, allocations: 256.7 kB / 0.8657 GB, free: 11.46 MB / 0.6387 GB
Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.004227/1.226, allocations: 1.914 MB / 0.8676 GB, free: 9.508 MB / 0.6387 GB
Notification: Performance of postOpt inlineArrayEqn (simulation): time 2.354e-05/1.227, allocations: 12 kB / 0.8676 GB, free: 9.496 MB / 0.6387 GB
Notification: Performance of postOpt constantLinearSystem (simulation): time 7.334e-06/1.227, allocations: 4 kB / 0.8676 GB, free: 9.492 MB / 0.6387 GB
Notification: Performance of postOpt simplifysemiLinear (simulation): time 1.379e-05/1.227, allocations: 11.92 kB / 0.8676 GB, free: 9.48 MB / 0.6387 GB
Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.007856/1.234, allocations: 3.958 MB / 0.8715 GB, free: 5.371 MB / 0.6387 GB
Notification: Performance of postOpt simplifyComplexFunction (simulation): time 9.378e-06/1.234, allocations: 0 / 0.8715 GB, free: 5.371 MB / 0.6387 GB
Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0008151/1.235, allocations: 203.8 kB / 0.8716 GB, free: 5.172 MB / 0.6387 GB
Notification: Performance of postOpt tearingSystem (simulation): time 0.001447/1.237, allocations: 0.705 MB / 0.8723 GB, free: 4.457 MB / 0.6387 GB
Notification: Performance of postOpt inputDerivativesUsed (simulation): time 9.655e-05/1.237, allocations: 31.98 kB / 0.8724 GB, free: 4.426 MB / 0.6387 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.003225/1.24, allocations: 3.794 MB / 0.8761 GB, free: 432 kB / 0.6387 GB
Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 2.354e-06/1.24, allocations: 0 / 0.8761 GB, free: 432 kB / 0.6387 GB
Notification: Performance of postOpt symbolicJacobian (simulation): time 0.3287/1.569, allocations: 1.81 MB / 0.8778 GB, free: 269.8 MB / 0.6387 GB
Notification: Performance of postOpt removeConstants (simulation): time 0.001334/1.57, allocations: 477.9 kB / 0.8783 GB, free: 269.7 MB / 0.6387 GB
Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0004897/1.571, allocations: 20.31 kB / 0.8783 GB, free: 269.7 MB / 0.6387 GB
Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.001219/1.572, allocations: 105.1 kB / 0.8784 GB, free: 269.7 MB / 0.6387 GB
Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0002284/1.572, allocations: 93.55 kB / 0.8785 GB, free: 269.7 MB / 0.6387 GB
Notification: Performance of postOpt collapseArrayExpressions (simulation): time 0.0001304/1.572, allocations: 51.52 kB / 0.8786 GB, free: 269.7 MB / 0.6387 GB
Notification: Performance of sorting global known variables: time 0.003496/1.576, allocations: 1.509 MB / 0.88 GB, free: 269.4 MB / 0.6387 GB
Notification: Performance of sort global known variables: time 7.62e-07/1.576, allocations: 0 / 0.88 GB, free: 269.4 MB / 0.6387 GB
Notification: Performance of remove unused functions: time 0.00866/1.585, allocations: 1.671 MB / 0.8817 GB, free: 269.3 MB / 0.6387 GB
Notification: Model statistics after passing the back-end for simulation:
 * Number of independent subsystems: 1
 * Number of states: 0 ()
 * Number of discrete variables: 3 ($whenCondition1,y.T_start,y.count)
 * Number of discrete states: 1 (y.count)
 * Number of clocked states: 0 ()
 * Top-level inputs: 0
Notification: Strong component statistics for simulation (99):
 * Single equations (assignments): 91
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 2
 * When equations: 2
 * If-equations: 0
 * Equation systems (not torn): 1
 * Torn equation systems: 3
 * Mixed (continuous/discrete) equation systems: 0
Notification: Equation system details (not torn):
 * Constant Jacobian (size): 0 systems
 * Linear Jacobian (size,density): 0 systems
 * Non-linear Jacobian (size): 1 system
   {1}
 * Without analytic Jacobian (size): 0 systems
Notification: Torn system details for strict tearing set:
 * Linear torn systems (#iteration vars, #inner vars, density): 1 system
   {(1,2,100.0%)}
 * Non-linear torn systems (#iteration vars, #inner vars): 2 systems
   {(2,6), (2,6)}
Notification: Performance of Backend phase and start with SimCode phase: time 0.002021/1.587, allocations: 0.6638 MB / 0.8823 GB, free: 269.2 MB / 0.6387 GB
Notification: Performance of simCode: created initialization part: time 0.02184/1.609, allocations: 25.53 MB / 0.9072 GB, free: 251.7 MB / 0.6387 GB
Notification: Performance of simCode: created event and clocks part: time 8.626e-06/1.609, allocations: 0 / 0.9072 GB, free: 251.7 MB / 0.6387 GB
Notification: Performance of simCode: created simulation system equations: time 0.001615/1.61, allocations: 0.7903 MB / 0.908 GB, free: 251.4 MB / 0.6387 GB
Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.005854/1.616, allocations: 1.039 MB / 0.909 GB, free: 251.1 MB / 0.6387 GB
Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.006621/1.623, allocations: 5.145 MB / 0.9141 GB, free: 246.4 MB / 0.6387 GB
Notification: Performance of simCode: some other stuff during SimCode phase: time 0.001056/1.624, allocations: 1.717 MB / 0.9157 GB, free: 245 MB / 0.6387 GB
Notification: Performance of simCode: alias equations: time 0.002047/1.626, allocations: 459 kB / 0.9162 GB, free: 244.7 MB / 0.6387 GB
Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0003336/1.626, allocations: 174.4 kB / 0.9163 GB, free: 244.6 MB / 0.6387 GB
Notification: Performance of SimCode: time 1.473e-06/1.626, allocations: 0 / 0.9163 GB, free: 244.6 MB / 0.6387 GB
Notification: Performance of Templates: time 0.09847/1.725, allocations: 68.49 MB / 0.9832 GB, free: 176.7 MB / 0.6387 GB
make -j1 -f Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine.makefile
Environment - environmentSimulation:
(rm -f Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine.pipe ; mkfifo Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine.pipe ; head -c 1048576 < Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine.pipe >> ../files/Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine.sim & ./Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine  -abortSlowSimulation -alarm=480 -lv LOG_STATS > Buildings_1.6_Buildings.Fluid.Movers.Examples.ControlledFlowMachine.pipe 2>&1)
Environment - environmentSimulation: