Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static.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.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static")
translateModel(Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static")
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.0008633/0.0008632, allocations: 98.27 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 0.005614/0.005614, allocations: 170.6 kB / 16.27 MB, free: 6.652 MB / 14.72 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo): time 1.491/1.491, allocations: 205.4 MB / 222.5 MB, free: 5.559 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 1.501/1.501, allocations: 252 MB / 0.5105 GB, free: 4.652 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 0.0005439/0.0005439, allocations: 15.98 kB / 0.6249 GB, free: 0.7305 MB / 0.5137 GB
Notification: Performance of FrontEnd - Absyn->SCode: time 0.5016/0.5022, allocations: 106.3 MB / 0.7287 GB, free: 11.27 MB / 0.545 GB
Notification: Performance of NFInst.instantiate(Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static): time 0.06004/0.5623, allocations: 68.23 MB / 0.7953 GB, free: 6.809 MB / 0.6075 GB
Notification: Performance of NFInst.instExpressions: time 0.02378/0.5861, allocations: 14.64 MB / 0.8096 GB, free: 8.137 MB / 0.6231 GB
Notification: Performance of NFInst.updateImplicitVariability: time 0.003325/0.5895, allocations: 63.56 kB / 0.8097 GB, free: 8.074 MB / 0.6231 GB
Notification: Performance of NFTyping.typeComponents: time 0.00299/0.5925, allocations: 0.7576 MB / 0.8104 GB, free: 7.312 MB / 0.6231 GB
Notification: Performance of NFTyping.typeBindings: time 0.007685/0.6002, allocations: 2.318 MB / 0.8127 GB, free: 4.988 MB / 0.6231 GB
Notification: Performance of NFTyping.typeClassSections: time 0.005204/0.6054, allocations: 1.792 MB / 0.8145 GB, free: 3.211 MB / 0.6231 GB
Notification: Performance of NFFlatten.flatten: time 0.00776/0.6132, allocations: 5.818 MB / 0.8201 GB, free: 13.38 MB / 0.6387 GB
Notification: Performance of NFFlatten.resolveConnections: time 0.002302/0.6155, allocations: 1.254 MB / 0.8214 GB, free: 12.09 MB / 0.6387 GB
Notification: Performance of NFEvalConstants.evaluate: time 0.003365/0.6189, allocations: 1.427 MB / 0.8228 GB, free: 10.66 MB / 0.6387 GB
Notification: Performance of NFSimplifyModel.simplify: time 0.002713/0.6217, allocations: 1.186 MB / 0.8239 GB, free: 9.465 MB / 0.6387 GB
Notification: Performance of NFPackage.collectConstants: time 0.0003887/0.6221, allocations: 64 kB / 0.824 GB, free: 9.402 MB / 0.6387 GB
Notification: Performance of NFFlatten.collectFunctions: time 0.00541/0.6275, allocations: 1.822 MB / 0.8258 GB, free: 7.578 MB / 0.6387 GB
Notification: Performance of NFScalarize.scalarize: time 0.0005658/0.6281, allocations: 322.4 kB / 0.8261 GB, free: 7.262 MB / 0.6387 GB
Notification: Performance of NFVerifyModel.verify: time 0.001547/0.6296, allocations: 0.8957 MB / 0.8269 GB, free: 6.355 MB / 0.6387 GB
Notification: Performance of NFConvertDAE.convert: time 0.006763/0.6364, allocations: 3.4 MB / 0.8303 GB, free: 2.945 MB / 0.6387 GB
Notification: Performance of FrontEnd - DAE generated: time 5.23e-06/0.6364, allocations: 0 / 0.8303 GB, free: 2.945 MB / 0.6387 GB
Notification: Performance of FrontEnd: time 2.264e-06/0.6365, allocations: 0 / 0.8303 GB, free: 2.945 MB / 0.6387 GB
Notification: Performance of Transformations before backend: time 4.402e-05/0.6365, allocations: 0 / 0.8303 GB, free: 2.945 MB / 0.6387 GB
Notification: Model statistics after passing the front-end and creating the data structures used by the back-end:
 * Number of equations: 294
 * Number of variables: 294
Notification: Performance of Generate backend data structure: time 0.003999/0.6405, allocations: 1.971 MB / 0.8322 GB, free: 0.9062 MB / 0.6387 GB
Notification: Performance of prepare preOptimizeDAE: time 5.252e-05/0.6406, allocations: 12.03 kB / 0.8322 GB, free: 0.8945 MB / 0.6387 GB
Notification: Performance of preOpt normalInlineFunction (simulation): time 0.005139/0.6457, allocations: 0.6817 MB / 0.8329 GB, free: 216 kB / 0.6387 GB
Notification: Performance of preOpt evaluateParameters (simulation): time 0.003289/0.649, allocations: 1.537 MB / 0.8344 GB, free: 14.62 MB / 0.6544 GB
Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0001485/0.6492, allocations: 128 kB / 0.8345 GB, free: 14.48 MB / 0.6544 GB
Notification: Performance of preOpt expandDerOperator (simulation): time 0.0001989/0.6494, allocations: 116 kB / 0.8346 GB, free: 14.37 MB / 0.6544 GB
Notification: Performance of preOpt clockPartitioning (simulation): time 0.003818/0.6533, allocations: 1.634 MB / 0.8362 GB, free: 12.64 MB / 0.6544 GB
Notification: Performance of preOpt findStateOrder (simulation): time 2.827e-05/0.6533, allocations: 7.938 kB / 0.8362 GB, free: 12.63 MB / 0.6544 GB
Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0001469/0.6535, allocations: 48 kB / 0.8362 GB, free: 12.59 MB / 0.6544 GB
Notification: Performance of preOpt inlineArrayEqn (simulation): time 4.803e-05/0.6535, allocations: 39.92 kB / 0.8363 GB, free: 12.55 MB / 0.6544 GB
Notification: Performance of preOpt removeEqualRHS (simulation): time 0.00452/0.658, allocations: 1.472 MB / 0.8377 GB, free: 11.07 MB / 0.6544 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 0.01005/0.6681, allocations: 7.194 MB / 0.8447 GB, free: 3.488 MB / 0.6544 GB
Notification: Performance of preOpt comSubExp (simulation): time 0.002257/0.6704, allocations: 0.8183 MB / 0.8455 GB, free: 2.664 MB / 0.6544 GB
Notification: Performance of preOpt resolveLoops (simulation): time 0.001602/0.672, allocations: 0.4988 MB / 0.846 GB, free: 2.164 MB / 0.6544 GB
Notification: Performance of preOpt evalFunc (simulation): time 0.001486/0.6735, allocations: 1.274 MB / 0.8473 GB, free: 0.6133 MB / 0.6544 GB
Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 5.069e-05/0.6736, allocations: 43.12 kB / 0.8473 GB, free: 0.5586 MB / 0.6544 GB
Notification: Performance of pre-optimization done (n=68): time 2.935e-06/0.6736, allocations: 4 kB / 0.8473 GB, free: 0.5547 MB / 0.6544 GB
Notification: Performance of matching and sorting (n=68): time 0.01018/0.6838, allocations: 2.252 MB / 0.8495 GB, free: 14.27 MB / 0.67 GB
Notification: Performance of inlineWhenForInitialization (initialization): time 7.855e-05/0.6839, allocations: 111.4 kB / 0.8496 GB, free: 14.14 MB / 0.67 GB
Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.002247/0.6861, allocations: 1.359 MB / 0.851 GB, free: 12.77 MB / 0.67 GB
Notification: Performance of collectPreVariables (initialization): time 0.0001403/0.6863, allocations: 41.7 kB / 0.851 GB, free: 12.72 MB / 0.67 GB
Notification: Performance of collectInitialEqns (initialization): time 0.0007062/0.687, allocations: 0.6879 MB / 0.8517 GB, free: 12.03 MB / 0.67 GB
Notification: Performance of collectInitialBindings (initialization): time 0.0002553/0.6873, allocations: 236.7 kB / 0.8519 GB, free: 11.8 MB / 0.67 GB
Notification: Performance of simplifyInitialFunctions (initialization): time 0.0001339/0.6874, allocations: 73.69 kB / 0.852 GB, free: 11.72 MB / 0.67 GB
Notification: Performance of setup shared object (initialization): time 0.0001359/0.6876, allocations: 341.9 kB / 0.8523 GB, free: 11.38 MB / 0.67 GB
Notification: Performance of preBalanceInitialSystem (initialization): time 0.001813/0.6894, allocations: 0.4938 MB / 0.8528 GB, free: 10.89 MB / 0.67 GB
Notification: Performance of partitionIndependentBlocks (initialization): time 0.002053/0.6914, allocations: 0.7783 MB / 0.8535 GB, free: 9.992 MB / 0.67 GB
Notification: Performance of analyzeInitialSystem (initialization): time 0.003503/0.695, allocations: 1.141 MB / 0.8546 GB, free: 8.77 MB / 0.67 GB
Notification: Performance of solveInitialSystemEqSystem (initialization): time 5.941e-06/0.695, allocations: 3.938 kB / 0.8546 GB, free: 8.766 MB / 0.67 GB
Notification: Performance of matching and sorting (n=108) (initialization): time 0.004787/0.6998, allocations: 1.562 MB / 0.8562 GB, free: 7.191 MB / 0.67 GB
Notification: Performance of prepare postOptimizeDAE: time 0.0002003/0.7, allocations: 276.9 kB / 0.8564 GB, free: 6.832 MB / 0.67 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.214e-05/0.7, allocations: 4 kB / 0.8564 GB, free: 6.828 MB / 0.67 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.001553/0.7016, allocations: 449.8 kB / 0.8569 GB, free: 6.387 MB / 0.67 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001352/0.7029, allocations: 259.6 kB / 0.8571 GB, free: 6.133 MB / 0.67 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.00147/0.7044, allocations: 1.079 MB / 0.8582 GB, free: 5.027 MB / 0.67 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.002427/0.7068, allocations: 278.7 kB / 0.8584 GB, free: 4.754 MB / 0.67 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0001142/0.707, allocations: 55.95 kB / 0.8585 GB, free: 4.699 MB / 0.67 GB
Notification: Performance of prepare postOptimizeDAE: time 1.096e-05/0.707, allocations: 4 kB / 0.8585 GB, free: 4.695 MB / 0.67 GB
Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.004409/0.7114, allocations: 1.406 MB / 0.8599 GB, free: 3.285 MB / 0.67 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.143e-05/0.7114, allocations: 8 kB / 0.8599 GB, free: 3.277 MB / 0.67 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.001422/0.7129, allocations: 438.6 kB / 0.8603 GB, free: 2.852 MB / 0.67 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.001333/0.7142, allocations: 251.6 kB / 0.8605 GB, free: 2.605 MB / 0.67 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.00148/0.7157, allocations: 1.079 MB / 0.8616 GB, free: 1.5 MB / 0.67 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.002192/0.7179, allocations: 254.7 kB / 0.8618 GB, free: 1.25 MB / 0.67 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0001111/0.718, allocations: 55.94 kB / 0.8619 GB, free: 1.195 MB / 0.67 GB
Notification: Model statistics after passing the back-end for initialization:
 * Number of independent subsystems: 28
 * Number of states: 0 ()
 * Number of discrete variables: 2 (heaPum.com.isOn,$PRE.heaPum.com.isOn)
 * Number of discrete states: 0 ()
 * Number of clocked states: 0 ()
 * Top-level inputs: 0
Notification: Strong component statistics for initialization (82):
 * Single equations (assignments): 81
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 0
 * When equations: 0
 * If-equations: 0
 * Equation systems (not torn): 0
 * Torn equation systems: 1
 * 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): 1 system
   {(4,23)}
Notification: Performance of prepare postOptimizeDAE: time 0.0008777/0.7189, allocations: 440.9 kB / 0.8623 GB, free: 0.7539 MB / 0.67 GB
Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0002901/0.7192, allocations: 142.3 kB / 0.8624 GB, free: 0.6133 MB / 0.67 GB
Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.004159/0.7234, allocations: 1.325 MB / 0.8637 GB, free: 15.27 MB / 0.6856 GB
Notification: Performance of postOpt inlineArrayEqn (simulation): time 1.479e-05/0.7234, allocations: 8 kB / 0.8637 GB, free: 15.26 MB / 0.6856 GB
Notification: Performance of postOpt constantLinearSystem (simulation): time 7.834e-06/0.7234, allocations: 7.875 kB / 0.8637 GB, free: 15.25 MB / 0.6856 GB
Notification: Performance of postOpt simplifysemiLinear (simulation): time 0.003494/0.7269, allocations: 1.135 MB / 0.8649 GB, free: 14.08 MB / 0.6856 GB
Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.008459/0.7354, allocations: 3.41 MB / 0.8682 GB, free: 10.46 MB / 0.6856 GB
Notification: Performance of postOpt simplifyComplexFunction (simulation): time 1.172e-05/0.7355, allocations: 4 kB / 0.8682 GB, free: 10.46 MB / 0.6856 GB
Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0009479/0.7364, allocations: 159.8 kB / 0.8683 GB, free: 10.3 MB / 0.6856 GB
Notification: Performance of postOpt tearingSystem (simulation): time 0.001465/0.7379, allocations: 429.2 kB / 0.8688 GB, free: 9.887 MB / 0.6856 GB
Notification: Performance of postOpt inputDerivativesUsed (simulation): time 6.303e-05/0.738, allocations: 27.91 kB / 0.8688 GB, free: 9.859 MB / 0.6856 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.001492/0.7395, allocations: 1.075 MB / 0.8698 GB, free: 8.758 MB / 0.6856 GB
Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 7.334e-06/0.7395, allocations: 11.94 kB / 0.8698 GB, free: 8.746 MB / 0.6856 GB
Notification: Performance of postOpt symbolicJacobian (simulation): time 0.004077/0.7436, allocations: 1.397 MB / 0.8712 GB, free: 7.281 MB / 0.6856 GB
Notification: Performance of postOpt removeConstants (simulation): time 0.000888/0.7445, allocations: 390.8 kB / 0.8716 GB, free: 6.879 MB / 0.6856 GB
Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.000193/0.7447, allocations: 20.11 kB / 0.8716 GB, free: 6.859 MB / 0.6856 GB
Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.0017/0.7464, allocations: 155.8 kB / 0.8717 GB, free: 6.707 MB / 0.6856 GB
Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0001268/0.7465, allocations: 52.25 kB / 0.8718 GB, free: 6.656 MB / 0.6856 GB
Notification: Performance of postOpt collapseArrayExpressions (simulation): time 0.0001057/0.7466, allocations: 47.95 kB / 0.8718 GB, free: 6.609 MB / 0.6856 GB
Notification: Performance of sorting global known variables: time 0.001636/0.7483, allocations: 0.9574 MB / 0.8728 GB, free: 5.652 MB / 0.6856 GB
Notification: Performance of sort global known variables: time 1.7e-07/0.7483, allocations: 0 / 0.8728 GB, free: 5.652 MB / 0.6856 GB
Notification: Performance of remove unused functions: time 0.002721/0.751, allocations: 0.9318 MB / 0.8737 GB, free: 4.719 MB / 0.6856 GB
Notification: Model statistics after passing the back-end for simulation:
 * Number of independent subsystems: 17
 * Number of states: 0 ()
 * Number of discrete variables: 1 (heaPum.com.isOn)
 * Number of discrete states: 1 (heaPum.com.isOn)
 * Number of clocked states: 0 ()
 * Top-level inputs: 0
Notification: Strong component statistics for simulation (42):
 * Single equations (assignments): 39
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 2
 * When equations: 0
 * If-equations: 0
 * Equation systems (not torn): 0
 * Torn equation systems: 1
 * 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): 1 system
   {(4,23)}
Notification: Performance of Backend phase and start with SimCode phase: time 0.001624/0.7527, allocations: 0.5898 MB / 0.8743 GB, free: 4.133 MB / 0.6856 GB
Notification: Performance of simCode: created initialization part: time 0.00721/0.7599, allocations: 1.838 MB / 0.8761 GB, free: 2.297 MB / 0.6856 GB
Notification: Performance of simCode: created event and clocks part: time 2.49e-05/0.76, allocations: 7.938 kB / 0.8761 GB, free: 2.289 MB / 0.6856 GB
Notification: Performance of simCode: created simulation system equations: time 0.002131/0.7621, allocations: 0.5373 MB / 0.8766 GB, free: 1.754 MB / 0.6856 GB
Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.006096/0.7682, allocations: 0.8075 MB / 0.8774 GB, free: 0.9609 MB / 0.6856 GB
Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.006049/0.7743, allocations: 3.127 MB / 0.8804 GB, free: 13.76 MB / 0.7012 GB
Notification: Performance of simCode: some other stuff during SimCode phase: time 0.0008495/0.7752, allocations: 1.207 MB / 0.8816 GB, free: 12.52 MB / 0.7012 GB
Notification: Performance of simCode: alias equations: time 0.001906/0.7771, allocations: 338.9 kB / 0.8819 GB, free: 12.2 MB / 0.7012 GB
Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0003349/0.7775, allocations: 123.3 kB / 0.882 GB, free: 12.07 MB / 0.7012 GB
Notification: Performance of SimCode: time 8.82e-07/0.7775, allocations: 0 / 0.882 GB, free: 12.07 MB / 0.7012 GB
Notification: Performance of Templates: time 0.4392/1.217, allocations: 37.76 MB / 0.9189 GB, free: 170.3 MB / 0.7169 GB
make -j1 -f Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static.makefile
Environment - environmentSimulation:
(rm -f Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static.pipe ; mkfifo Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static.pipe ; head -c 1048576 < Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static.pipe >> ../files/Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static.sim & ./Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static  -abortSlowSimulation -alarm=480 -lv LOG_STATS > Buildings_maint.7.0.x_Buildings.Fluid.HeatPumps.Validation.ReciprocatingWaterToWater_Static.pipe 2>&1)
Environment - environmentSimulation: