Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement.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: translateModel(Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement")
translateModel(Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement,tolerance=1e-06,outputFormat="empty",numberOfIntervals=5000,variableFilter="",fileNamePrefix="Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement")
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.0009275/0.0009273, allocations: 98.77 kB / 15.05 MB, free: 1.105 MB / 14.72 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.0008954/0.0008954, allocations: 177.3 kB / 15.94 MB, free: 228 kB / 14.72 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 3.2.3+maint.om/package.mo): time 1.281/1.281, allocations: 205.4 MB / 222.1 MB, free: 5.516 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 1.619/1.619, allocations: 292.5 MB / 0.5497 GB, free: 14.63 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 0.0005736/0.0005737, allocations: 17.94 kB / 0.6735 GB, free: 26.25 MB / 0.5294 GB
Notification: Performance of FrontEnd - Absyn->SCode: time 0.2146/0.2152, allocations: 116.3 MB / 0.7871 GB, free: 11.95 MB / 0.6075 GB
Notification: Performance of NFInst.instantiate(Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement): time 0.0382/0.2534, allocations: 33.89 MB / 0.8202 GB, free: 9.953 MB / 0.6387 GB
Notification: Performance of NFInst.instExpressions: time 0.01479/0.2682, allocations: 10.61 MB / 0.8306 GB, free: 15.33 MB / 0.6544 GB
Notification: Performance of NFInst.updateImplicitVariability: time 0.001759/0.27, allocations: 47.69 kB / 0.8306 GB, free: 15.28 MB / 0.6544 GB
Notification: Performance of NFTyping.typeComponents: time 0.002018/0.2721, allocations: 0.6219 MB / 0.8312 GB, free: 14.66 MB / 0.6544 GB
Notification: Performance of NFTyping.typeBindings: time 0.006216/0.2783, allocations: 1.95 MB / 0.8331 GB, free: 12.7 MB / 0.6544 GB
Notification: Performance of NFTyping.typeClassSections: time 0.004517/0.2828, allocations: 1.487 MB / 0.8346 GB, free: 11.24 MB / 0.6544 GB
Notification: Performance of NFFlatten.flatten: time 0.004449/0.2873, allocations: 2.072 MB / 0.8366 GB, free: 9.168 MB / 0.6544 GB
Notification: Performance of NFFlatten.resolveConnections: time 0.001264/0.2886, allocations: 0.8724 MB / 0.8375 GB, free: 8.266 MB / 0.6544 GB
Notification: Performance of NFEvalConstants.evaluate: time 0.001962/0.2905, allocations: 0.9341 MB / 0.8384 GB, free: 7.328 MB / 0.6544 GB
Notification: Performance of NFSimplifyModel.simplify: time 0.001075/0.2916, allocations: 0.6416 MB / 0.839 GB, free: 6.684 MB / 0.6544 GB
Notification: Performance of NFPackage.collectConstants: time 0.0001328/0.2918, allocations: 52 kB / 0.8391 GB, free: 6.633 MB / 0.6544 GB
Notification: Performance of NFFlatten.collectFunctions: time 0.003157/0.2949, allocations: 1.104 MB / 0.8401 GB, free: 5.527 MB / 0.6544 GB
Notification: Performance of NFScalarize.scalarize: time 0.000279/0.2952, allocations: 223.1 kB / 0.8403 GB, free: 5.309 MB / 0.6544 GB
Notification: Performance of NFVerifyModel.verify: time 0.0004349/0.2957, allocations: 301 kB / 0.8406 GB, free: 5.008 MB / 0.6544 GB
Notification: Performance of NFConvertDAE.convert: time 0.002229/0.2979, allocations: 1.866 MB / 0.8425 GB, free: 3.137 MB / 0.6544 GB
Notification: Performance of FrontEnd - DAE generated: time 3.587e-06/0.2979, allocations: 4 kB / 0.8425 GB, free: 3.133 MB / 0.6544 GB
Notification: Performance of FrontEnd: time 2.384e-06/0.2979, allocations: 3.938 kB / 0.8425 GB, free: 3.129 MB / 0.6544 GB
Notification: Performance of Transformations before backend: time 2.329e-05/0.298, allocations: 0 / 0.8425 GB, free: 3.129 MB / 0.6544 GB
Notification: Model statistics after passing the front-end and creating the data structures used by the back-end:
 * Number of equations: 214
 * Number of variables: 214
Notification: Performance of Generate backend data structure: time 0.002423/0.3004, allocations: 1.479 MB / 0.8439 GB, free: 1.594 MB / 0.6544 GB
Notification: Performance of prepare preOptimizeDAE: time 3.495e-05/0.3004, allocations: 8.031 kB / 0.8439 GB, free: 1.586 MB / 0.6544 GB
Notification: Performance of preOpt normalInlineFunction (simulation): time 0.0003322/0.3008, allocations: 150.3 kB / 0.8441 GB, free: 1.438 MB / 0.6544 GB
Notification: Performance of preOpt evaluateParameters (simulation): time 0.001558/0.3023, allocations: 1.041 MB / 0.8451 GB, free: 364 kB / 0.6544 GB
Notification: Performance of preOpt simplifyIfEquations (simulation): time 4.843e-05/0.3024, allocations: 77.94 kB / 0.8452 GB, free: 284 kB / 0.6544 GB
Notification: Performance of preOpt expandDerOperator (simulation): time 0.0001163/0.3025, allocations: 92 kB / 0.8452 GB, free: 192 kB / 0.6544 GB
Notification: Performance of preOpt clockPartitioning (simulation): time 0.001275/0.3038, allocations: 0.8894 MB / 0.8461 GB, free: 15.27 MB / 0.67 GB
Notification: Performance of preOpt findStateOrder (simulation): time 2.425e-05/0.3038, allocations: 8 kB / 0.8461 GB, free: 15.26 MB / 0.67 GB
Notification: Performance of preOpt replaceEdgeChange (simulation): time 7.195e-05/0.3039, allocations: 36 kB / 0.8462 GB, free: 15.22 MB / 0.67 GB
Notification: Performance of preOpt inlineArrayEqn (simulation): time 3.283e-05/0.304, allocations: 20 kB / 0.8462 GB, free: 15.2 MB / 0.67 GB
Notification: Performance of preOpt removeEqualRHS (simulation): time 0.0009706/0.3049, allocations: 0.6402 MB / 0.8468 GB, free: 14.56 MB / 0.67 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 0.004435/0.3094, allocations: 4.328 MB / 0.851 GB, free: 9.949 MB / 0.67 GB
Notification: Performance of preOpt comSubExp (simulation): time 0.0008354/0.3102, allocations: 0.505 MB / 0.8515 GB, free: 9.438 MB / 0.67 GB
Notification: Performance of preOpt evalFunc (simulation): time 0.0006125/0.3108, allocations: 0.594 MB / 0.8521 GB, free: 8.715 MB / 0.67 GB
Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 3.333e-05/0.3109, allocations: 47.08 kB / 0.8521 GB, free: 8.66 MB / 0.67 GB
Notification: Performance of pre-optimization done (n=57): time 2.795e-06/0.3109, allocations: 0 / 0.8521 GB, free: 8.66 MB / 0.67 GB
Notification: Performance of matching and sorting (n=57): time 0.00231/0.3132, allocations: 1.231 MB / 0.8533 GB, free: 7.34 MB / 0.67 GB
Notification: Performance of inlineWhenForInitialization (initialization): time 3.173e-05/0.3133, allocations: 55.97 kB / 0.8534 GB, free: 7.273 MB / 0.67 GB
Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.001015/0.3143, allocations: 0.9144 MB / 0.8543 GB, free: 6.336 MB / 0.67 GB
Notification: Performance of collectPreVariables (initialization): time 5.816e-05/0.3144, allocations: 41.7 kB / 0.8543 GB, free: 6.289 MB / 0.67 GB
Notification: Performance of collectInitialEqns (initialization): time 0.0003573/0.3147, allocations: 0.5113 MB / 0.8548 GB, free: 5.77 MB / 0.67 GB
Notification: Performance of collectInitialBindings (initialization): time 0.000148/0.3149, allocations: 197.1 kB / 0.855 GB, free: 5.574 MB / 0.67 GB
Notification: Performance of simplifyInitialFunctions (initialization): time 3.292e-05/0.3149, allocations: 16 kB / 0.855 GB, free: 5.559 MB / 0.67 GB
Notification: Performance of setup shared object (initialization): time 0.0001018/0.315, allocations: 337.9 kB / 0.8554 GB, free: 5.223 MB / 0.67 GB
Notification: Performance of preBalanceInitialSystem (initialization): time 0.0002917/0.3153, allocations: 201.9 kB / 0.8555 GB, free: 5.027 MB / 0.67 GB
Notification: Performance of partitionIndependentBlocks (initialization): time 0.0004233/0.3157, allocations: 406.2 kB / 0.8559 GB, free: 4.562 MB / 0.67 GB
Notification: Performance of analyzeInitialSystem (initialization): time 0.0003725/0.3161, allocations: 271.1 kB / 0.8562 GB, free: 4.297 MB / 0.67 GB
Notification: Performance of solveInitialSystemEqSystem (initialization): time 3.146e-06/0.3161, allocations: 0 / 0.8562 GB, free: 4.297 MB / 0.67 GB
Notification: Performance of matching and sorting (n=94) (initialization): time 0.00143/0.3176, allocations: 0.8544 MB / 0.857 GB, free: 3.422 MB / 0.67 GB
Notification: Performance of prepare postOptimizeDAE: time 0.0004224/0.318, allocations: 1.313 MB / 0.8583 GB, free: 2.012 MB / 0.67 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.601e-05/0.318, allocations: 8 kB / 0.8583 GB, free: 2.004 MB / 0.67 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.00055/0.3186, allocations: 155.3 kB / 0.8585 GB, free: 1.84 MB / 0.67 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0004482/0.319, allocations: 139.8 kB / 0.8586 GB, free: 1.703 MB / 0.67 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.003437/0.3225, allocations: 4.985 MB / 0.8635 GB, free: 12.29 MB / 0.6856 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.0008981/0.3234, allocations: 123.3 kB / 0.8636 GB, free: 12.16 MB / 0.6856 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 6.513e-05/0.3235, allocations: 31.98 kB / 0.8636 GB, free: 12.13 MB / 0.6856 GB
Notification: Performance of prepare postOptimizeDAE: time 8.426e-06/0.3235, allocations: 0 / 0.8636 GB, free: 12.13 MB / 0.6856 GB
Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.001182/0.3247, allocations: 0.7095 MB / 0.8643 GB, free: 11.41 MB / 0.6856 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.232e-05/0.3247, allocations: 8 kB / 0.8643 GB, free: 11.4 MB / 0.6856 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.0003089/0.325, allocations: 131.8 kB / 0.8644 GB, free: 11.26 MB / 0.6856 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0004363/0.3255, allocations: 135.8 kB / 0.8646 GB, free: 11.13 MB / 0.6856 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.004175/0.3297, allocations: 5.999 MB / 0.8704 GB, free: 4.582 MB / 0.6856 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.0008875/0.3306, allocations: 111.4 kB / 0.8705 GB, free: 4.473 MB / 0.6856 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 5.319e-05/0.3306, allocations: 28 kB / 0.8706 GB, free: 4.445 MB / 0.6856 GB
Notification: Model statistics after passing the back-end for initialization:
 * Number of independent subsystems: 15
 * 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 (78):
 * Single equations (assignments): 73
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 1
 * When equations: 0
 * If-equations: 0
 * Equation systems (linear and non-linear blocks): 0
 * Torn equation systems: 4
 * Mixed (continuous/discrete) equation systems: 0
Notification: Torn system details for strict tearing set:
 * Linear torn systems: 3 {(1,100.0%) 3,(1,100.0%) 3,(1,100.0%) 3}
 * Non-linear torn systems: 1 {1 4}
Notification: Performance of prepare postOptimizeDAE: time 0.0006413/0.3313, allocations: 380.8 kB / 0.8709 GB, free: 4.062 MB / 0.6856 GB
Notification: Performance of postOpt lateInlineFunction (simulation): time 0.000161/0.3314, allocations: 106.7 kB / 0.871 GB, free: 3.957 MB / 0.6856 GB
Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.001159/0.3326, allocations: 0.7095 MB / 0.8717 GB, free: 3.234 MB / 0.6856 GB
Notification: Performance of postOpt inlineArrayEqn (simulation): time 8.967e-06/0.3326, allocations: 4 kB / 0.8717 GB, free: 3.23 MB / 0.6856 GB
Notification: Performance of postOpt constantLinearSystem (simulation): time 5.45e-06/0.3326, allocations: 4 kB / 0.8717 GB, free: 3.227 MB / 0.6856 GB
Notification: Performance of postOpt simplifysemiLinear (simulation): time 0.0008355/0.3335, allocations: 0.6417 MB / 0.8724 GB, free: 2.543 MB / 0.6856 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 0.002494/0.336, allocations: 1.839 MB / 0.8741 GB, free: 0.6094 MB / 0.6856 GB
Notification: Performance of postOpt simplifyComplexFunction (simulation): time 6.853e-06/0.336, allocations: 4 kB / 0.8742 GB, free: 0.6055 MB / 0.6856 GB
Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0003422/0.3364, allocations: 87.89 kB / 0.8742 GB, free: 0.5195 MB / 0.6856 GB
Notification: Performance of postOpt tearingSystem (simulation): time 0.0002858/0.3366, allocations: 119.3 kB / 0.8743 GB, free: 400 kB / 0.6856 GB
Notification: Performance of postOpt inputDerivativesUsed (simulation): time 3.309e-05/0.3367, allocations: 12 kB / 0.8744 GB, free: 388 kB / 0.6856 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.003272/0.34, allocations: 4.99 MB / 0.8792 GB, free: 10.96 MB / 0.7012 GB
Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 1.893e-06/0.34, allocations: 0 / 0.8792 GB, free: 10.96 MB / 0.7012 GB
Notification: Performance of postOpt symbolicJacobian (simulation): time 0.001496/0.3415, allocations: 1.085 MB / 0.8803 GB, free: 9.812 MB / 0.7012 GB
Notification: Performance of postOpt removeConstants (simulation): time 0.0004493/0.342, allocations: 283.6 kB / 0.8806 GB, free: 9.516 MB / 0.7012 GB
Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0001024/0.3421, allocations: 12 kB / 0.8806 GB, free: 9.504 MB / 0.7012 GB
Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.0005754/0.3426, allocations: 62.89 kB / 0.8806 GB, free: 9.445 MB / 0.7012 GB
Notification: Performance of postOpt findZeroCrossings (simulation): time 7.392e-05/0.3427, allocations: 44.45 kB / 0.8807 GB, free: 9.402 MB / 0.7012 GB
Notification: Performance of postOpt collapseArrayExpressions (simulation): time 4.289e-05/0.3428, allocations: 27.98 kB / 0.8807 GB, free: 9.375 MB / 0.7012 GB
Notification: Performance of sorting global known variables: time 0.0007615/0.3436, allocations: 0.6254 MB / 0.8813 GB, free: 8.738 MB / 0.7012 GB
Notification: Performance of sort global known variables: time 2.61e-07/0.3436, allocations: 0 / 0.8813 GB, free: 8.738 MB / 0.7012 GB
Notification: Performance of remove unused functions: time 0.002214/0.3458, allocations: 0.7288 MB / 0.882 GB, free: 8.008 MB / 0.7012 GB
Notification: Model statistics after passing the back-end for simulation:
 * Number of independent subsystems: 5
 * Number of states: 4 (hex.vol1.dynBal.U,hex.vol2.dynBal.U,hex.capFil1.T,hex.capFil2.T)
 * 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 (47):
 * Single equations (assignments): 41
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 2
 * When equations: 0
 * If-equations: 0
 * Equation systems (linear and non-linear blocks): 0
 * Torn equation systems: 4
 * Mixed (continuous/discrete) equation systems: 0
Notification: Torn system details for strict tearing set:
 * Linear torn systems: 3 {(1,100.0%) 3,(1,100.0%) 3,(1,100.0%) 3}
 * Non-linear torn systems: 1 {1 3}
Notification: Performance of Backend phase and start with SimCode phase: time 0.0008819/0.3467, allocations: 476.9 kB / 0.8825 GB, free: 7.543 MB / 0.7012 GB
Notification: Performance of simCode: created initialization part: time 0.002381/0.3491, allocations: 1.78 MB / 0.8842 GB, free: 5.664 MB / 0.7012 GB
Notification: Performance of simCode: created event and clocks part: time 5.51e-06/0.3491, allocations: 0 / 0.8842 GB, free: 5.664 MB / 0.7012 GB
Notification: Performance of simCode: created simulation system equations: time 0.0007179/0.3498, allocations: 0.6204 MB / 0.8848 GB, free: 5.004 MB / 0.7012 GB
Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.002498/0.3523, allocations: 0.5324 MB / 0.8853 GB, free: 4.477 MB / 0.7012 GB
Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.003359/0.3557, allocations: 2.454 MB / 0.8877 GB, free: 1.992 MB / 0.7012 GB
Notification: Performance of simCode: some other stuff during SimCode phase: time 0.0006369/0.3563, allocations: 1.112 MB / 0.8888 GB, free: 0.8516 MB / 0.7012 GB
Notification: Performance of simCode: alias equations: time 0.000864/0.3572, allocations: 224.9 kB / 0.889 GB, free: 0.6406 MB / 0.7012 GB
Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0001615/0.3574, allocations: 79.42 kB / 0.8891 GB, free: 0.5625 MB / 0.7012 GB
Notification: Performance of SimCode: time 4.51e-07/0.3574, allocations: 0 / 0.8891 GB, free: 0.5625 MB / 0.7012 GB
Notification: Performance of Templates: time 0.03454/0.3919, allocations: 23.88 MB / 0.9124 GB, free: 8.98 MB / 0.7325 GB
make -j1 -f Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement.makefile
Environment - environmentSimulation:
(rm -f Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement.pipe ; mkfifo Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement.pipe ; head -c 1048576 < Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement.pipe >> ../files/Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement.sim & ./Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement  -abortSlowSimulation -alarm=480 -lv LOG_STATS > Buildings_8_Buildings.Fluid.Geothermal.Boreholes.BaseClasses.Examples.HexInternalElement.pipe 2>&1)
Environment - environmentSimulation: