Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr BuildingSystems_BuildingSystems.Media.Examples.WaterDerivativeCheck.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 4.0.0+maint.om/package.mo", uses=false) loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/NcDataReader2 2.5.1-master/package.mo", uses=false) loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/package.mo", uses=false) Using package BuildingSystems with version 2.0.0-beta (/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/package.mo) Using package NcDataReader2 with version 2.5.1 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/NcDataReader2 2.5.1-master/package.mo) Using package Modelica with version 4.0.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 4.0.0+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(BuildingSystems.Media.Examples.WaterDerivativeCheck,fileNamePrefix="BuildingSystems_BuildingSystems_Media_Examples_WaterDerivativeCheck",fmuType="me",version="2.0",platforms={"static"}) "" <> buildModelFMU(BuildingSystems.Media.Examples.WaterDerivativeCheck,fileNamePrefix="BuildingSystems_BuildingSystems_Media_Examples_WaterDerivativeCheck",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 0.0007426/0.0007425, allocations: 84.38 kB / 15.06 MB, free: 1.09 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.0008048/0.0008048, allocations: 168.7 kB / 15.95 MB, free: 204 kB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 4.0.0+maint.om/package.mo): time 1.271/1.271, allocations: 223.2 MB / 240 MB, free: 5.422 MB / 190.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/NcDataReader2 2.5.1-master/package.mo): time 0.001718/0.001718, allocations: 255.1 kB / 291.3 MB, free: 1.98 MB / 238.1 MB [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:5:3-5:34:writable] Warning: Got element f_alp that was not referenced in the package.order file. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:6:3-6:35:writable] Warning: Elements in the package.mo-file need to be in the same relative order as the package.order file. Got element named f_lay but it was already added because it was not the next element in the list at that time. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:6:3-6:35:writable] Warning: Got element f_lay that was not referenced in the package.order file. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:7:3-7:37:writable] Warning: Elements in the package.mo-file need to be in the same relative order as the package.order file. Got element named f_loss but it was already added because it was not the next element in the list at that time. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:7:3-7:37:writable] Warning: Got element f_loss that was not referenced in the package.order file. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:8:3-8:33:writable] Warning: Elements in the package.mo-file need to be in the same relative order as the package.order file. Got element named f_pv but it was already added because it was not the next element in the list at that time. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:8:3-8:33:writable] Warning: Got element f_pv that was not referenced in the package.order file. [/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/Buildings/Airvolumes/Parameter/package.mo:2:1-34:14:writable] Warning: f_pv was referenced in the package.order file, but was not found in package.mo, f_pv/package.mo or f_pv.mo. Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/BuildingSystems 2.0.0-master/package.mo): time 0.7759/0.7759, allocations: 144.7 MB / 487.2 MB, free: 7.125 MB / 350.1 MB Notification: Performance of FrontEnd - loaded program: time 0.0003837/0.0003837, allocations: 13.77 kB / 0.5686 GB, free: 38.43 MB / 430.1 MB Notification: Performance of FrontEnd - Absyn->SCode: time 0.1291/0.1295, allocations: 83.09 MB / 0.6497 GB, free: 3.469 MB / 446.1 MB Notification: Performance of NFInst.instantiate(BuildingSystems.Media.Examples.WaterDerivativeCheck): time 0.001224/0.1308, allocations: 0.9726 MB / 0.6507 GB, free: 2.484 MB / 446.1 MB Notification: Performance of NFInst.instExpressions: time 0.003381/0.1342, allocations: 3.042 MB / 0.6536 GB, free: 15.44 MB / 462.1 MB Notification: Performance of NFInst.updateImplicitVariability: time 2.515e-05/0.1342, allocations: 0 / 0.6536 GB, free: 15.44 MB / 462.1 MB Notification: Performance of NFTyping.typeComponents: time 1.459e-05/0.1342, allocations: 0 / 0.6536 GB, free: 15.44 MB / 462.1 MB Notification: Performance of NFTyping.typeBindings: time 4.604e-05/0.1343, allocations: 12.36 kB / 0.6536 GB, free: 15.43 MB / 462.1 MB Notification: Performance of NFTyping.typeClassSections: time 0.0004322/0.1347, allocations: 85.09 kB / 0.6537 GB, free: 15.35 MB / 462.1 MB Notification: Performance of NFFlatten.flatten: time 6.184e-05/0.1348, allocations: 27.92 kB / 0.6537 GB, free: 15.32 MB / 462.1 MB Notification: Performance of NFFlatten.resolveConnections: time 3.207e-05/0.1348, allocations: 4.922 kB / 0.6537 GB, free: 15.32 MB / 462.1 MB Notification: Performance of NFEvalConstants.evaluate: time 4.551e-05/0.1349, allocations: 23.92 kB / 0.6538 GB, free: 15.29 MB / 462.1 MB Notification: Performance of NFSimplifyModel.simplify: time 5.667e-05/0.135, allocations: 16.98 kB / 0.6538 GB, free: 15.28 MB / 462.1 MB Notification: Performance of NFPackage.collectConstants: time 1.19e-05/0.135, allocations: 4 kB / 0.6538 GB, free: 15.27 MB / 462.1 MB Notification: Performance of NFFlatten.collectFunctions: time 0.0001952/0.1352, allocations: 55.83 kB / 0.6538 GB, free: 15.22 MB / 462.1 MB Notification: Performance of NFScalarize.scalarize: time 1.319e-05/0.1352, allocations: 12.55 kB / 0.6539 GB, free: 15.21 MB / 462.1 MB Notification: Performance of NFVerifyModel.verify: time 2.635e-05/0.1352, allocations: 30.2 kB / 0.6539 GB, free: 15.17 MB / 462.1 MB Notification: Performance of NFConvertDAE.convert: time 0.0001042/0.1353, allocations: 31.95 kB / 0.6539 GB, free: 15.14 MB / 462.1 MB Notification: Performance of FrontEnd - DAE generated: time 5.24e-06/0.1354, allocations: 5.25 kB / 0.6539 GB, free: 15.14 MB / 462.1 MB Notification: Performance of FrontEnd: time 1.713e-06/0.1354, allocations: 0 / 0.6539 GB, free: 15.14 MB / 462.1 MB Notification: Performance of Transformations before backend: time 3.827e-06/0.1354, allocations: 0 / 0.6539 GB, free: 15.14 MB / 462.1 MB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 7 * Number of variables: 7 Notification: Performance of Generate backend data structure: time 0.0003115/0.1357, allocations: 344.7 kB / 0.6543 GB, free: 14.75 MB / 462.1 MB Notification: Performance of prepare preOptimizeDAE: time 3.943e-05/0.1357, allocations: 8.031 kB / 0.6543 GB, free: 14.75 MB / 462.1 MB Notification: Performance of preOpt introduceOutputAliases (simulation): time 3.834e-05/0.1358, allocations: 35.12 kB / 0.6543 GB, free: 14.7 MB / 462.1 MB Notification: Performance of preOpt normalInlineFunction (simulation): time 7.917e-05/0.1359, allocations: 4.531 kB / 0.6543 GB, free: 14.7 MB / 462.1 MB Notification: Performance of preOpt evaluateParameters (simulation): time 9.799e-05/0.136, allocations: 172.2 kB / 0.6545 GB, free: 14.49 MB / 462.1 MB Notification: Performance of preOpt simplifyIfEquations (simulation): time 1.097e-05/0.136, allocations: 4 kB / 0.6545 GB, free: 14.49 MB / 462.1 MB Notification: Performance of preOpt expandDerOperator (simulation): time 2.068e-05/0.136, allocations: 4 kB / 0.6545 GB, free: 14.48 MB / 462.1 MB Notification: Performance of preOpt clockPartitioning (simulation): time 0.0001119/0.1361, allocations: 54.39 kB / 0.6545 GB, free: 14.43 MB / 462.1 MB Notification: Performance of preOpt findStateOrder (simulation): time 6.763e-06/0.1361, allocations: 0 / 0.6545 GB, free: 14.43 MB / 462.1 MB Notification: Performance of preOpt replaceEdgeChange (simulation): time 1.005e-05/0.1362, allocations: 0.875 kB / 0.6545 GB, free: 14.43 MB / 462.1 MB Notification: Performance of preOpt inlineArrayEqn (simulation): time 7.114e-06/0.1362, allocations: 0 / 0.6545 GB, free: 14.43 MB / 462.1 MB Notification: Performance of preOpt removeEqualRHS (simulation): time 5.199e-05/0.1362, allocations: 26.5 kB / 0.6545 GB, free: 14.4 MB / 462.1 MB Notification: Performance of preOpt removeSimpleEquations (simulation): time 0.0001536/0.1364, allocations: 169.5 kB / 0.6547 GB, free: 14.19 MB / 462.1 MB Notification: Performance of preOpt comSubExp (simulation): time 9.092e-05/0.1365, allocations: 54.48 kB / 0.6548 GB, free: 14.12 MB / 462.1 MB Notification: Performance of preOpt resolveLoops (simulation): time 2.759e-05/0.1365, allocations: 20.8 kB / 0.6548 GB, free: 14.1 MB / 462.1 MB Notification: Performance of preOpt evalFunc (simulation): time 0.0006346/0.1372, allocations: 0.589 MB / 0.6554 GB, free: 13.41 MB / 462.1 MB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 2.064e-05/0.1372, allocations: 32.22 kB / 0.6554 GB, free: 13.37 MB / 462.1 MB Notification: Performance of pre-optimization done (n=5): time 1.092e-06/0.1372, allocations: 0 / 0.6554 GB, free: 13.37 MB / 462.1 MB Notification: Performance of matching and sorting (n=7): time 0.0005079/0.1377, allocations: 303.1 kB / 0.6557 GB, free: 13.02 MB / 462.1 MB Notification: Performance of inlineWhenForInitialization (initialization): time 2.89e-05/0.1378, allocations: 51.94 kB / 0.6557 GB, free: 12.96 MB / 462.1 MB Notification: Performance of selectInitializationVariablesDAE (initialization): time 6.198e-05/0.1378, allocations: 106.9 kB / 0.6558 GB, free: 12.84 MB / 462.1 MB Notification: Performance of collectPreVariables (initialization): time 1.529e-05/0.1379, allocations: 25.7 kB / 0.6558 GB, free: 12.81 MB / 462.1 MB Notification: Performance of collectInitialEqns (initialization): time 3.517e-05/0.1379, allocations: 92.02 kB / 0.6559 GB, free: 12.72 MB / 462.1 MB Notification: Performance of collectInitialBindings (initialization): time 2.403e-05/0.1379, allocations: 28.8 kB / 0.656 GB, free: 12.69 MB / 462.1 MB Notification: Performance of simplifyInitialFunctions (initialization): time 3.426e-06/0.1379, allocations: 0 / 0.656 GB, free: 12.69 MB / 462.1 MB Notification: Performance of setup shared object (initialization): time 9.156e-05/0.138, allocations: 319.5 kB / 0.6563 GB, free: 12.37 MB / 462.1 MB Notification: Performance of preBalanceInitialSystem (initialization): time 2.708e-05/0.1381, allocations: 12 kB / 0.6563 GB, free: 12.36 MB / 462.1 MB Notification: Performance of partitionIndependentBlocks (initialization): time 4.808e-05/0.1381, allocations: 51.02 kB / 0.6563 GB, free: 12.29 MB / 462.1 MB Notification: Performance of analyzeInitialSystem (initialization): time 3.776e-05/0.1382, allocations: 18.69 kB / 0.6563 GB, free: 12.28 MB / 462.1 MB Notification: Performance of solveInitialSystemEqSystem (initialization): time 1.022e-06/0.1382, allocations: 0 / 0.6563 GB, free: 12.28 MB / 462.1 MB Notification: Performance of matching and sorting (n=12) (initialization): time 0.000134/0.1383, allocations: 94.33 kB / 0.6564 GB, free: 12.18 MB / 462.1 MB Notification: Performance of prepare postOptimizeDAE: time 2.34e-05/0.1383, allocations: 9.875 kB / 0.6564 GB, free: 12.17 MB / 462.1 MB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 5.33e-06/0.1383, allocations: 1.719 kB / 0.6564 GB, free: 12.17 MB / 462.1 MB Notification: Performance of postOpt tearingSystem (initialization): time 1.259e-05/0.1384, allocations: 4 kB / 0.6565 GB, free: 12.17 MB / 462.1 MB Notification: Performance of postOpt solveSimpleEquations (initialization): time 7.567e-05/0.1384, allocations: 27.88 kB / 0.6565 GB, free: 12.14 MB / 462.1 MB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 6.452e-06/0.1385, allocations: 8 kB / 0.6565 GB, free: 12.13 MB / 462.1 MB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 3.534e-05/0.1385, allocations: 4 kB / 0.6565 GB, free: 12.13 MB / 462.1 MB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 1.022e-05/0.1385, allocations: 9.031 kB / 0.6565 GB, free: 12.12 MB / 462.1 MB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 6 * 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 (12): * Single equations (assignments): 12 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 0 * Mixed (continuous/discrete) equation systems: 0 Notification: Performance of prepare postOptimizeDAE: time 7.496e-05/0.1386, allocations: 125.8 kB / 0.6566 GB, free: 11.99 MB / 462.1 MB Notification: Performance of postOpt lateInlineFunction (simulation): time 2.766e-05/0.1386, allocations: 7.906 kB / 0.6566 GB, free: 11.98 MB / 462.1 MB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 2.877e-05/0.1387, allocations: 11.97 kB / 0.6566 GB, free: 11.97 MB / 462.1 MB Notification: Performance of postOpt inlineArrayEqn (simulation): time 2.965e-06/0.1387, allocations: 7.922 kB / 0.6566 GB, free: 11.96 MB / 462.1 MB Notification: Performance of postOpt constantLinearSystem (simulation): time 4.678e-06/0.1387, allocations: 3.953 kB / 0.6566 GB, free: 11.96 MB / 462.1 MB Notification: Performance of postOpt simplifysemiLinear (simulation): time 2.685e-06/0.1387, allocations: 0 / 0.6566 GB, free: 11.96 MB / 462.1 MB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.0002287/0.1389, allocations: 174.2 kB / 0.6568 GB, free: 11.74 MB / 462.1 MB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 1.523e-06/0.1389, allocations: 0 / 0.6568 GB, free: 11.74 MB / 462.1 MB Notification: Performance of postOpt solveSimpleEquations (simulation): time 8.138e-05/0.139, allocations: 16 kB / 0.6568 GB, free: 11.73 MB / 462.1 MB Notification: Performance of postOpt tearingSystem (simulation): time 4.308e-06/0.139, allocations: 4 kB / 0.6568 GB, free: 11.72 MB / 462.1 MB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 6.763e-06/0.139, allocations: 0 / 0.6568 GB, free: 11.72 MB / 462.1 MB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 1.603e-06/0.1391, allocations: 4 kB / 0.6568 GB, free: 11.72 MB / 462.1 MB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 1.012e-06/0.1391, allocations: 0 / 0.6568 GB, free: 11.72 MB / 462.1 MB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.0001586/0.1392, allocations: 171.4 kB / 0.657 GB, free: 11.54 MB / 462.1 MB Notification: Performance of postOpt removeConstants (simulation): time 5.27e-05/0.1393, allocations: 89.14 kB / 0.6571 GB, free: 11.43 MB / 462.1 MB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 1.255e-05/0.1393, allocations: 3.938 kB / 0.6571 GB, free: 11.43 MB / 462.1 MB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 9.977e-05/0.1394, allocations: 4 kB / 0.6571 GB, free: 11.42 MB / 462.1 MB Notification: Performance of postOpt findZeroCrossings (simulation): time 1.112e-05/0.1394, allocations: 0 / 0.6571 GB, free: 11.42 MB / 462.1 MB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 8.917e-06/0.1394, allocations: 11.98 kB / 0.6571 GB, free: 11.41 MB / 462.1 MB Notification: Performance of sorting global known variables: time 3.075e-05/0.1395, allocations: 79.28 kB / 0.6572 GB, free: 11.33 MB / 462.1 MB Notification: Performance of sort global known variables: time 2.4e-07/0.1395, allocations: 0 / 0.6572 GB, free: 11.33 MB / 462.1 MB Notification: Performance of remove unused functions: time 0.0002347/0.1397, allocations: 15.95 kB / 0.6572 GB, free: 11.32 MB / 462.1 MB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 1 * Number of states: 3 (hLiqSym,cpSym,cvSym) * 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 (7): * Single equations (assignments): 7 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 0 * Mixed (continuous/discrete) equation systems: 0 Notification: Performance of Backend phase and start with SimCode phase: time 0.0003821/0.1401, allocations: 0.709 MB / 0.6579 GB, free: 10.58 MB / 462.1 MB Notification: Performance of simCode: created initialization part: time 0.0001014/0.1402, allocations: 44.09 kB / 0.6579 GB, free: 10.54 MB / 462.1 MB Notification: Performance of simCode: created event and clocks part: time 2.204e-06/0.1402, allocations: 0 / 0.6579 GB, free: 10.54 MB / 462.1 MB Notification: Performance of simCode: created simulation system equations: time 2.225e-05/0.1403, allocations: 15.98 kB / 0.6579 GB, free: 10.52 MB / 462.1 MB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.0002499/0.1405, allocations: 8 kB / 0.658 GB, free: 10.51 MB / 462.1 MB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.0008871/0.1414, allocations: 0.688 MB / 0.6586 GB, free: 9.762 MB / 462.1 MB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.000211/0.1416, allocations: 0.6887 MB / 0.6593 GB, free: 9.047 MB / 462.1 MB Notification: Performance of simCode: alias equations: time 5.341e-05/0.1417, allocations: 8.062 kB / 0.6593 GB, free: 9.039 MB / 462.1 MB Notification: Performance of simCode: all other stuff during SimCode phase: time 3.202e-05/0.1417, allocations: 11.44 kB / 0.6593 GB, free: 9.027 MB / 462.1 MB Notification: Performance of SimCode: time 2.71e-07/0.1417, allocations: 3.938 kB / 0.6593 GB, free: 9.023 MB / 462.1 MB Notification: Performance of buildModelFMU: Generate the FMI files: time 0.01119/0.1529, allocations: 1.416 MB / 0.6607 GB, free: 7.738 MB / 462.1 MB Notification: Performance of buildModelFMU: configured platform static using cached values: time 0.0001606/0.1531, allocations: 182.5 kB / 0.6609 GB, free: 7.504 MB / 462.1 MB Notification: Performance of buildModelFMU: Generate platform static: time 1.542/1.695, allocations: 0 / 0.6609 GB, free: 7.504 MB / 462.1 MB (rm -f BuildingSystems_BuildingSystems.Media.Examples.WaterDerivativeCheck.pipe ; mkfifo BuildingSystems_BuildingSystems.Media.Examples.WaterDerivativeCheck.pipe ; head -c 1048576 < BuildingSystems_BuildingSystems.Media.Examples.WaterDerivativeCheck.pipe >> ../files/BuildingSystems_BuildingSystems.Media.Examples.WaterDerivativeCheck.sim & /home/hudson/saved_omc/OMSimulator/install/linux/bin/OMSimulator --tempDir=temp_BuildingSystems_BuildingSystems_Media_Examples_WaterDerivativeCheck_fmu --startTime=0 --stopTime=1 --timeout=50 --tolerance=1e-08 BuildingSystems_BuildingSystems_Media_Examples_WaterDerivativeCheck.fmu > BuildingSystems_BuildingSystems.Media.Examples.WaterDerivativeCheck.pipe 2>&1) Environment - environmentSimulation: