Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Buildings_8_Buildings.Fluid.Examples.Performance.Example1v1.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 8.1.4-maint.8.1.x/package.mo", uses=false) Using package Buildings with version 8.1.4 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 8.1.4-maint.8.1.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: "" <> buildModelFMU(Buildings.Fluid.Examples.Performance.Example1v1,fileNamePrefix="Buildings_8_Buildings_Fluid_Examples_Performance_Example1v1",fmuType="me",version="2.0",platforms={"static"}) "" <> buildModelFMU(Buildings.Fluid.Examples.Performance.Example1v1,fileNamePrefix="Buildings_8_Buildings_Fluid_Examples_Performance_Example1v1",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 0.0009667/0.0009671, allocations: 92.16 kB / 15.06 MB, free: 1.098 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.0009216/0.0009214, allocations: 172.7 kB / 15.95 MB, free: 208 kB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo): time 1.543/1.543, allocations: 205.4 MB / 222.1 MB, free: 5.539 MB / 174.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 8.1.4-maint.8.1.x/package.mo): time 1.819/1.819, allocations: 292.7 MB / 0.5499 GB, free: 14.54 MB / 462.1 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 0.0005077/0.0005078, allocations: 16.41 kB / 0.6738 GB, free: 26.08 MB / 0.5294 GB Notification: Performance of FrontEnd - Absyn->SCode: time 0.2219/0.2224, allocations: 116.3 MB / 0.7874 GB, free: 11.85 MB / 0.6075 GB Notification: Performance of NFInst.instantiate(Buildings.Fluid.Examples.Performance.Example1v1): time 0.06122/0.2837, allocations: 66.85 MB / 0.8527 GB, free: 8.812 MB / 0.67 GB Notification: Performance of NFInst.instExpressions: time 0.0288/0.3126, allocations: 18.88 MB / 0.8711 GB, free: 5.898 MB / 0.6856 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.003281/0.3159, allocations: 79.44 kB / 0.8712 GB, free: 5.82 MB / 0.6856 GB Notification: Performance of NFTyping.typeComponents: time 0.002611/0.3185, allocations: 0.6637 MB / 0.8718 GB, free: 5.152 MB / 0.6856 GB Notification: Performance of NFTyping.typeBindings: time 0.005794/0.3243, allocations: 1.919 MB / 0.8737 GB, free: 3.227 MB / 0.6856 GB Notification: Performance of NFTyping.typeClassSections: time 0.004738/0.3291, allocations: 1.568 MB / 0.8752 GB, free: 1.672 MB / 0.6856 GB Notification: Performance of NFFlatten.flatten: time 0.009716/0.3388, allocations: 9.028 MB / 0.8841 GB, free: 8.613 MB / 0.7012 GB Notification: Performance of NFFlatten.resolveConnections: time 0.008339/0.3472, allocations: 5.314 MB / 0.8892 GB, free: 3.258 MB / 0.7012 GB Notification: Performance of NFEvalConstants.evaluate: time 0.007431/0.3547, allocations: 2.684 MB / 0.8919 GB, free: 0.5625 MB / 0.7012 GB Notification: Performance of NFSimplifyModel.simplify: time 0.004918/0.3596, allocations: 2.314 MB / 0.8941 GB, free: 14.24 MB / 0.7169 GB Notification: Performance of NFPackage.collectConstants: time 0.001024/0.3607, allocations: 128 kB / 0.8943 GB, free: 14.11 MB / 0.7169 GB Notification: Performance of NFFlatten.collectFunctions: time 0.003899/0.3646, allocations: 1.014 MB / 0.8952 GB, free: 13.1 MB / 0.7169 GB Notification: Performance of NFScalarize.scalarize: time 0.001489/0.3661, allocations: 0.6105 MB / 0.8958 GB, free: 12.48 MB / 0.7169 GB Notification: Performance of NFVerifyModel.verify: time 0.00193/0.3681, allocations: 0.6445 MB / 0.8965 GB, free: 11.83 MB / 0.7169 GB Notification: Performance of NFConvertDAE.convert: time 0.005242/0.3733, allocations: 3.48 MB / 0.8999 GB, free: 8.344 MB / 0.7169 GB Notification: Performance of FrontEnd - DAE generated: time 6.342e-06/0.3734, allocations: 0 / 0.8999 GB, free: 8.344 MB / 0.7169 GB Notification: Performance of FrontEnd: time 2.295e-06/0.3734, allocations: 0 / 0.8999 GB, free: 8.344 MB / 0.7169 GB Notification: Performance of Transformations before backend: time 0.0001855/0.3736, allocations: 0 / 0.8999 GB, free: 8.344 MB / 0.7169 GB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 398 * Number of variables: 398 Notification: Performance of Generate backend data structure: time 0.008763/0.3823, allocations: 3.866 MB / 0.9036 GB, free: 4.398 MB / 0.7169 GB Notification: Performance of prepare preOptimizeDAE: time 4.428e-05/0.3824, allocations: 11.97 kB / 0.9037 GB, free: 4.387 MB / 0.7169 GB Notification: Performance of preOpt introduceOutputAliases (simulation): time 0.0006758/0.3831, allocations: 232 kB / 0.9039 GB, free: 4.148 MB / 0.7169 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.002483/0.3856, allocations: 0.5734 MB / 0.9044 GB, free: 3.57 MB / 0.7169 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.005554/0.3911, allocations: 2.454 MB / 0.9068 GB, free: 1.055 MB / 0.7169 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0001502/0.3913, allocations: 139.8 kB / 0.907 GB, free: 0.918 MB / 0.7169 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0005229/0.3919, allocations: 184 kB / 0.9071 GB, free: 0.7383 MB / 0.7169 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.4728/0.8647, allocations: 2.404 MB / 0.9095 GB, free: 43.97 MB / 0.7169 GB Notification: Performance of preOpt findStateOrder (simulation): time 5.155e-05/0.8648, allocations: 8.594 kB / 0.9095 GB, free: 43.97 MB / 0.7169 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0002236/0.865, allocations: 68.12 kB / 0.9096 GB, free: 43.97 MB / 0.7169 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 4.543e-05/0.865, allocations: 39.78 kB / 0.9096 GB, free: 43.97 MB / 0.7169 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.004392/0.8694, allocations: 2.026 MB / 0.9116 GB, free: 43.95 MB / 0.7169 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 0.01565/0.8851, allocations: 12.13 MB / 0.9234 GB, free: 38.17 MB / 0.7169 GB Notification: Performance of preOpt comSubExp (simulation): time 0.002814/0.888, allocations: 1.557 MB / 0.9249 GB, free: 38.11 MB / 0.7169 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.001655/0.8896, allocations: 1.099 MB / 0.926 GB, free: 38.08 MB / 0.7169 GB Notification: Performance of preOpt evalFunc (simulation): time 0.00728/0.8969, allocations: 4.083 MB / 0.93 GB, free: 36.41 MB / 0.7169 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 0.001731/0.8987, allocations: 0.8868 MB / 0.9309 GB, free: 36.35 MB / 0.7169 GB Notification: Performance of preOpt simplifyInStream (simulation): time 0.001933/0.9007, allocations: 449 kB / 0.9313 GB, free: 36.29 MB / 0.7169 GB Notification: Performance of pre-optimization done (n=96): time 4.298e-06/0.9007, allocations: 0 / 0.9313 GB, free: 36.29 MB / 0.7169 GB Notification: Performance of matching and sorting (n=96): time 0.01583/0.9165, allocations: 5.209 MB / 0.9364 GB, free: 35.59 MB / 0.7169 GB Notification: Performance of inlineWhenForInitialization (initialization): time 4.379e-05/0.9166, allocations: 63.12 kB / 0.9364 GB, free: 35.52 MB / 0.7169 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.005057/0.9217, allocations: 2.997 MB / 0.9394 GB, free: 35.28 MB / 0.7169 GB Notification: Performance of collectPreVariables (initialization): time 0.0003902/0.9221, allocations: 57.23 kB / 0.9394 GB, free: 35.25 MB / 0.7169 GB Notification: Performance of collectInitialEqns (initialization): time 0.00144/0.9235, allocations: 1.413 MB / 0.9408 GB, free: 34.89 MB / 0.7169 GB Notification: Performance of collectInitialBindings (initialization): time 0.0004476/0.924, allocations: 346.2 kB / 0.9411 GB, free: 34.67 MB / 0.7169 GB Notification: Performance of simplifyInitialFunctions (initialization): time 9.038e-05/0.9241, allocations: 30.84 kB / 0.9412 GB, free: 34.67 MB / 0.7169 GB Notification: Performance of setup shared object (initialization): time 0.0001217/0.9242, allocations: 361.9 kB / 0.9415 GB, free: 34.36 MB / 0.7169 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.001437/0.9257, allocations: 0.6932 MB / 0.9422 GB, free: 34.36 MB / 0.7169 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.001718/0.9274, allocations: 1.492 MB / 0.9436 GB, free: 33.43 MB / 0.7169 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.001579/0.929, allocations: 0.9023 MB / 0.9445 GB, free: 33.36 MB / 0.7169 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 9.809e-06/0.929, allocations: 3.281 kB / 0.9445 GB, free: 33.36 MB / 0.7169 GB Notification: Performance of matching and sorting (n=181) (initialization): time 0.006608/0.9356, allocations: 2.953 MB / 0.9474 GB, free: 33 MB / 0.7169 GB Notification: Performance of prepare postOptimizeDAE: time 0.0002726/0.9359, allocations: 0.5392 MB / 0.9479 GB, free: 32.35 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 2.321e-05/0.9359, allocations: 17.75 kB / 0.948 GB, free: 32.34 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.002663/0.9386, allocations: 0.7766 MB / 0.9487 GB, free: 32.29 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.00129/0.9399, allocations: 299 kB / 0.949 GB, free: 32.29 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.002175/0.9421, allocations: 2.18 MB / 0.9511 GB, free: 31.21 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.002883/0.945, allocations: 242.9 kB / 0.9514 GB, free: 31.18 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.00016/0.9452, allocations: 79.02 kB / 0.9514 GB, free: 31.18 MB / 0.7169 GB Notification: Performance of prepare postOptimizeDAE: time 2.299e-05/0.9452, allocations: 2.219 kB / 0.9514 GB, free: 31.18 MB / 0.7169 GB Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.003794/0.949, allocations: 2.303 MB / 0.9537 GB, free: 31.07 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 2.297e-05/0.949, allocations: 14.31 kB / 0.9537 GB, free: 31.07 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.00132/0.9504, allocations: 0.5881 MB / 0.9543 GB, free: 31.03 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001037/0.9514, allocations: 286.5 kB / 0.9545 GB, free: 31.02 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.007045/0.9585, allocations: 6.508 MB / 0.9609 GB, free: 28.03 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.002603/0.9611, allocations: 242.6 kB / 0.9611 GB, free: 27.94 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0002373/0.9614, allocations: 70.19 kB / 0.9612 GB, free: 27.93 MB / 0.7169 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 63 * Number of states: 0 () * Number of discrete variables: 8 ($whenCondition1,$PRE.pulse.T_start,pulse.T_start,$PRE.pulse.count,pulse.count,from_dp.y,nRes.y,allowFlowReversal.y) * Number of discrete states: 0 () * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for initialization (133): * Single equations (assignments): 129 * Array equations: 1 * Algorithm blocks: 1 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 2 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 2 {1 40,2 5} Notification: Performance of prepare postOptimizeDAE: time 0.001506/0.9629, allocations: 0.8207 MB / 0.962 GB, free: 27.62 MB / 0.7169 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0006742/0.9636, allocations: 298 kB / 0.9623 GB, free: 27.46 MB / 0.7169 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.00457/0.9681, allocations: 2.49 MB / 0.9647 GB, free: 26.78 MB / 0.7169 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 2.025e-05/0.9682, allocations: 13.31 kB / 0.9647 GB, free: 26.78 MB / 0.7169 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 3.326e-06/0.9682, allocations: 0 / 0.9647 GB, free: 26.78 MB / 0.7169 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 0.003338/0.9715, allocations: 2.183 MB / 0.9669 GB, free: 26 MB / 0.7169 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 postOpt removeSimpleEquations (simulation): time 0.01084/0.9824, allocations: 4.701 MB / 0.9715 GB, free: 24.41 MB / 0.7169 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 8.877e-06/0.9824, allocations: 0 / 0.9715 GB, free: 24.41 MB / 0.7169 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0007477/0.9832, allocations: 160.7 kB / 0.9716 GB, free: 24.36 MB / 0.7169 GB Notification: Performance of postOpt tearingSystem (simulation): time 0.001122/0.9843, allocations: 0.5423 MB / 0.9721 GB, free: 24.2 MB / 0.7169 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 9.205e-05/0.9844, allocations: 36.11 kB / 0.9722 GB, free: 24.19 MB / 0.7169 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.001884/0.9863, allocations: 2.082 MB / 0.9742 GB, free: 22.93 MB / 0.7169 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 3.016e-06/0.9864, allocations: 5.938 kB / 0.9742 GB, free: 22.93 MB / 0.7169 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.006359/0.9927, allocations: 3.34 MB / 0.9775 GB, free: 22 MB / 0.7169 GB Notification: Performance of postOpt removeConstants (simulation): time 0.00218/0.995, allocations: 0.5552 MB / 0.978 GB, free: 21.67 MB / 0.7169 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0008035/0.9958, allocations: 23.42 kB / 0.978 GB, free: 21.67 MB / 0.7169 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.002247/0.998, allocations: 199.7 kB / 0.9782 GB, free: 21.59 MB / 0.7169 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0001618/0.9982, allocations: 71.98 kB / 0.9783 GB, free: 21.56 MB / 0.7169 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 0.0001086/0.9983, allocations: 35.05 kB / 0.9783 GB, free: 21.55 MB / 0.7169 GB Notification: Performance of sorting global known variables: time 0.003569/1.002, allocations: 2.051 MB / 0.9803 GB, free: 21.02 MB / 0.7169 GB Notification: Performance of sort global known variables: time 2.81e-07/1.002, allocations: 3.375 kB / 0.9803 GB, free: 21.02 MB / 0.7169 GB Notification: Performance of remove unused functions: time 0.00542/1.007, allocations: 1.484 MB / 0.9818 GB, free: 20.88 MB / 0.7169 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 3 * Number of states: 2 (pump.vol.dynBal.U,hea.outCon.T) * Number of discrete variables: 3 ($whenCondition1,pulse.T_start,pulse.count) * Number of discrete states: 1 (pulse.count) * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for simulation (58): * Single equations (assignments): 50 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 4 * When equations: 2 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 2 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 2 {2 5,1 40} Notification: Performance of Backend phase and start with SimCode phase: time 0.006249/1.014, allocations: 4.01 MB / 0.9857 GB, free: 19.1 MB / 0.7169 GB Notification: Performance of simCode: created initialization part: time 0.005594/1.019, allocations: 3.248 MB / 0.9889 GB, free: 16.71 MB / 0.7169 GB Notification: Performance of simCode: created event and clocks part: time 6.392e-06/1.019, allocations: 4 kB / 0.9889 GB, free: 16.71 MB / 0.7169 GB Notification: Performance of simCode: created simulation system equations: time 0.001426/1.021, allocations: 0.8269 MB / 0.9897 GB, free: 16.14 MB / 0.7169 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.008057/1.029, allocations: 1.556 MB / 0.9912 GB, free: 14.82 MB / 0.7169 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.04751/1.076, allocations: 21.25 MB / 1.012 GB, free: 9.035 MB / 0.7325 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.002158/1.079, allocations: 2.041 MB / 1.014 GB, free: 6.969 MB / 0.7325 GB Notification: Performance of simCode: alias equations: time 0.003288/1.082, allocations: 0.6679 MB / 1.015 GB, free: 6.297 MB / 0.7325 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.002093/1.084, allocations: 1.171 MB / 1.016 GB, free: 5.125 MB / 0.7325 GB Notification: Performance of SimCode: time 3.096e-06/1.084, allocations: 0 / 1.016 GB, free: 5.125 MB / 0.7325 GB Notification: Performance of buildModelFMU: Generate the FMI files: time 0.1437/1.228, allocations: 84.71 MB / 1.098 GB, free: 1.656 MB / 0.8106 GB Notification: Performance of buildModelFMU: configured platform static using cached values: time 0.0001844/1.228, allocations: 247.8 kB / 1.099 GB, free: 1.324 MB / 0.8106 GB Notification: Performance of buildModelFMU: Generate platform static: time 4.232/5.46, allocations: 0 / 1.099 GB, free: 1.324 MB / 0.8106 GB (rm -f Buildings_8_Buildings.Fluid.Examples.Performance.Example1v1.pipe ; mkfifo Buildings_8_Buildings.Fluid.Examples.Performance.Example1v1.pipe ; head -c 1048576 < Buildings_8_Buildings.Fluid.Examples.Performance.Example1v1.pipe >> ../files/Buildings_8_Buildings.Fluid.Examples.Performance.Example1v1.sim & /home/hudson/saved_omc/OMSimulator/install/linux/bin/OMSimulator --tempDir=temp_Buildings_8_Buildings_Fluid_Examples_Performance_Example1v1_fmu --startTime=0 --stopTime=20 --timeout=50 --tolerance=1e-06 Buildings_8_Buildings_Fluid_Examples_Performance_Example1v1.fmu > Buildings_8_Buildings.Fluid.Examples.Performance.Example1v1.pipe 2>&1) Environment - environmentSimulation: