Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries --ompython_omhome=/usr Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.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/Buildings 9.1.3-maint.9.1.x/package.mo", uses=false) Using package Buildings with version 9.1.3 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 9.1.3-maint.9.1.x/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: translateModel(Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5000,variableFilter="time|roo.T|bou0.T|sha.vol.T|oriChiTop.m_flow|oriBot.m_flow|oriChiBot.m_flow|con.u_s|con.u_m|con.y",fileNamePrefix="Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume") translateModel(Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5000,variableFilter="time|roo.T|bou0.T|sha.vol.T|oriChiTop.m_flow|oriBot.m_flow|oriChiBot.m_flow|con.u_s|con.u_m|con.y",fileNamePrefix="Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume") Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.001695/0.001695, allocations: 105.6 kB / 16.41 MB, free: 6.512 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.001598/0.001599, allocations: 189.7 kB / 17.34 MB, free: 5.738 MB / 14.72 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 4.0.0+maint.om/package.mo): time 1.487/1.487, allocations: 222.9 MB / 241 MB, free: 15.15 MB / 206.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 9.1.3-maint.9.1.x/package.mo): time 2.444/2.444, allocations: 390.2 MB / 0.6655 GB, free: 0.5938 MB / 0.5294 GB Notification: Performance of FrontEnd - loaded program: time 0.001303/0.001303, allocations: 63.89 kB / 0.9515 GB, free: 7.621 MB / 0.7325 GB Notification: Performance of FrontEnd - Absyn->SCode: time 1.165/1.167, allocations: 140.4 MB / 1.089 GB, free: 5.484 MB / 0.8575 GB Notification: Performance of NFInst.instantiate(Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume): time 0.3206/1.487, allocations: 235.9 MB / 1.319 GB, free: 1.605 MB / 1.045 GB Notification: Performance of NFInst.instExpressions: time 0.01947/1.507, allocations: 10.42 MB / 1.329 GB, free: 7.164 MB / 1.061 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.004582/1.511, allocations: 63.62 kB / 1.329 GB, free: 7.102 MB / 1.061 GB Notification: Performance of NFTyping.typeComponents: time 0.005029/1.517, allocations: 1.189 MB / 1.33 GB, free: 5.906 MB / 1.061 GB Notification: Performance of NFTyping.typeBindings: time 0.01385/1.53, allocations: 3.66 MB / 1.334 GB, free: 2.23 MB / 1.061 GB Notification: Performance of NFTyping.typeClassSections: time 0.007799/1.538, allocations: 2.07 MB / 1.336 GB, free: 168 kB / 1.061 GB Notification: Performance of NFFlatten.flatten: time 0.01026/1.549, allocations: 4.455 MB / 1.34 GB, free: 11.7 MB / 1.076 GB Notification: Performance of NFFlatten.resolveConnections: time 0.004553/1.553, allocations: 1.583 MB / 1.342 GB, free: 10.09 MB / 1.076 GB Notification: Performance of NFEvalConstants.evaluate: time 0.005026/1.558, allocations: 1.623 MB / 1.343 GB, free: 8.457 MB / 1.076 GB Notification: Performance of NFSimplifyModel.simplify: time 0.003925/1.562, allocations: 1.493 MB / 1.345 GB, free: 6.965 MB / 1.076 GB Notification: Performance of NFPackage.collectConstants: time 0.0007765/1.563, allocations: 184 kB / 1.345 GB, free: 6.785 MB / 1.076 GB Notification: Performance of NFFlatten.collectFunctions: time 0.008084/1.571, allocations: 3.242 MB / 1.348 GB, free: 3.535 MB / 1.076 GB Notification: Performance of NFScalarize.scalarize: time 0.001347/1.572, allocations: 0.7011 MB / 1.349 GB, free: 2.832 MB / 1.076 GB Notification: Performance of NFVerifyModel.verify: time 0.002731/1.575, allocations: 1.061 MB / 1.35 GB, free: 1.766 MB / 1.076 GB Notification: Performance of NFConvertDAE.convert: time 0.00955/1.585, allocations: 3.814 MB / 1.354 GB, free: 13.94 MB / 1.092 GB Notification: Performance of FrontEnd - DAE generated: time 5.841e-06/1.585, allocations: 0 / 1.354 GB, free: 13.94 MB / 1.092 GB Notification: Performance of FrontEnd: time 1.903e-06/1.585, allocations: 0 / 1.354 GB, free: 13.94 MB / 1.092 GB Notification: Performance of Transformations before backend: time 0.0001139/1.585, allocations: 0 / 1.354 GB, free: 13.94 MB / 1.092 GB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 344 * Number of variables: 344 Notification: Performance of Generate backend data structure: time 0.007509/1.592, allocations: 2.482 MB / 1.356 GB, free: 11.4 MB / 1.092 GB Notification: Performance of prepare preOptimizeDAE: time 4.312e-05/1.592, allocations: 16.02 kB / 1.356 GB, free: 11.39 MB / 1.092 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.003658/1.596, allocations: 0.5206 MB / 1.357 GB, free: 10.86 MB / 1.092 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.002484/1.599, allocations: 1.283 MB / 1.358 GB, free: 9.523 MB / 1.092 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 9.046e-05/1.599, allocations: 110.6 kB / 1.358 GB, free: 9.414 MB / 1.092 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0002007/1.599, allocations: 132 kB / 1.358 GB, free: 9.285 MB / 1.092 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.002944/1.602, allocations: 1.67 MB / 1.36 GB, free: 7.547 MB / 1.092 GB Notification: Performance of preOpt findStateOrder (simulation): time 3.877e-05/1.602, allocations: 11.91 kB / 1.36 GB, free: 7.535 MB / 1.092 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0001355/1.602, allocations: 52 kB / 1.36 GB, free: 7.484 MB / 1.092 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 8.04e-05/1.602, allocations: 66.58 kB / 1.36 GB, free: 7.418 MB / 1.092 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.002474/1.605, allocations: 1.451 MB / 1.361 GB, free: 5.961 MB / 1.092 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 0.009125/1.614, allocations: 6.988 MB / 1.368 GB, free: 14.51 MB / 1.107 GB Notification: Performance of preOpt comSubExp (simulation): time 0.001867/1.616, allocations: 1.195 MB / 1.369 GB, free: 13.27 MB / 1.107 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.0009232/1.617, allocations: 0.6128 MB / 1.37 GB, free: 12.65 MB / 1.107 GB Notification: Performance of preOpt evalFunc (simulation): time 0.0008756/1.617, allocations: 0.8633 MB / 1.371 GB, free: 11.6 MB / 1.107 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 0.001035/1.619, allocations: 0.6063 MB / 1.371 GB, free: 10.98 MB / 1.107 GB Notification: Performance of pre-optimization done (n=110): time 3.677e-06/1.619, allocations: 0 / 1.371 GB, free: 10.98 MB / 1.107 GB Notification: Performance of matching and sorting (n=110): time 0.003092/1.622, allocations: 1.576 MB / 1.373 GB, free: 9.406 MB / 1.107 GB Notification: Performance of inlineWhenForInitialization (initialization): time 6.903e-05/1.622, allocations: 86.11 kB / 1.373 GB, free: 9.301 MB / 1.107 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.001494/1.623, allocations: 1.199 MB / 1.374 GB, free: 8.082 MB / 1.107 GB Notification: Performance of collectPreVariables (initialization): time 9.63e-05/1.623, allocations: 45.7 kB / 1.374 GB, free: 8.031 MB / 1.107 GB Notification: Performance of collectInitialEqns (initialization): time 0.0005904/1.624, allocations: 0.6737 MB / 1.375 GB, free: 7.352 MB / 1.107 GB Notification: Performance of collectInitialBindings (initialization): time 0.0003693/1.624, allocations: 386.4 kB / 1.375 GB, free: 6.969 MB / 1.107 GB Notification: Performance of simplifyInitialFunctions (initialization): time 0.0002992/1.625, allocations: 182.6 kB / 1.375 GB, free: 6.785 MB / 1.107 GB Notification: Performance of setup shared object (initialization): time 0.0001404/1.625, allocations: 341.9 kB / 1.376 GB, free: 6.445 MB / 1.107 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.0007162/1.625, allocations: 428.6 kB / 1.376 GB, free: 6.023 MB / 1.107 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.0008194/1.626, allocations: 0.5595 MB / 1.377 GB, free: 5.426 MB / 1.107 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.001553/1.628, allocations: 1.009 MB / 1.378 GB, free: 4.383 MB / 1.107 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 5.49e-06/1.628, allocations: 0 / 1.378 GB, free: 4.383 MB / 1.107 GB Notification: Performance of matching and sorting (n=126) (initialization): time 0.002205/1.63, allocations: 1.222 MB / 1.379 GB, free: 3.156 MB / 1.107 GB Notification: Performance of prepare postOptimizeDAE: time 2.514e-05/1.63, allocations: 8 kB / 1.379 GB, free: 3.148 MB / 1.107 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.276e-05/1.63, allocations: 3.938 kB / 1.379 GB, free: 3.145 MB / 1.107 GB Notification: Performance of postOpt tearingSystem (initialization): time 2.609e-05/1.63, allocations: 8 kB / 1.379 GB, free: 3.137 MB / 1.107 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0009595/1.631, allocations: 212 kB / 1.379 GB, free: 2.93 MB / 1.107 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 2.056e-05/1.631, allocations: 15.94 kB / 1.379 GB, free: 2.914 MB / 1.107 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.001315/1.633, allocations: 102.9 kB / 1.379 GB, free: 2.812 MB / 1.107 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 8.482e-05/1.633, allocations: 32 kB / 1.379 GB, free: 2.781 MB / 1.107 GB Notification: Performance of preBalanceInitialSystem (initialization_lambda0): time 0.001421/1.634, allocations: 0.7401 MB / 1.38 GB, free: 2.035 MB / 1.107 GB Notification: Performance of partitionIndependentBlocks (initialization_lambda0): time 0.0008227/1.635, allocations: 0.5401 MB / 1.38 GB, free: 1.461 MB / 1.107 GB Notification: Performance of analyzeInitialSystem (initialization_lambda0): time 0.001546/1.636, allocations: 0.9893 MB / 1.381 GB, free: 452 kB / 1.107 GB Notification: Performance of solveInitialSystemEqSystem (initialization_lambda0): time 4.007e-06/1.636, allocations: 3.938 kB / 1.381 GB, free: 448 kB / 1.107 GB Notification: Performance of matching and sorting (n=126) (initialization_lambda0): time 0.002189/1.639, allocations: 1.195 MB / 1.383 GB, free: 15.23 MB / 1.123 GB Notification: Performance of prepare postOptimizeDAE: time 1.71e-05/1.639, allocations: 4 kB / 1.383 GB, free: 15.23 MB / 1.123 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 5.701e-06/1.639, allocations: 4 kB / 1.383 GB, free: 15.22 MB / 1.123 GB Notification: Performance of postOpt tearingSystem (initialization): time 1.76e-05/1.639, allocations: 15.92 kB / 1.383 GB, free: 15.21 MB / 1.123 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0009462/1.64, allocations: 203.7 kB / 1.383 GB, free: 15.01 MB / 1.123 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 1.752e-05/1.64, allocations: 15.92 kB / 1.383 GB, free: 14.99 MB / 1.123 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.001286/1.641, allocations: 79.48 kB / 1.383 GB, free: 14.91 MB / 1.123 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 8.017e-05/1.641, allocations: 40 kB / 1.383 GB, free: 14.88 MB / 1.123 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 11 * Number of states: 0 () * Number of discrete variables: 5 ($PRE.mRoo_flow.nextTimeEvent,$whenCondition1,mRoo_flow.nextTimeEventScaled,$PRE.mRoo_flow.nextTimeEventScaled,mRoo_flow.nextTimeEvent) * Number of discrete states: 0 () * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for initialization (126): * Single equations (assignments): 126 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (not torn): 0 * Torn equation systems: 0 * Mixed (continuous/discrete) equation systems: 0 Notification: Performance of prepare postOptimizeDAE: time 0.0004238/1.642, allocations: 236.1 kB / 1.383 GB, free: 14.64 MB / 1.123 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0002586/1.642, allocations: 150.2 kB / 1.383 GB, free: 14.49 MB / 1.123 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.002437/1.644, allocations: 1.247 MB / 1.384 GB, free: 13.23 MB / 1.123 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 1.578e-05/1.644, allocations: 12 kB / 1.384 GB, free: 13.22 MB / 1.123 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 8.295e-06/1.644, allocations: 0 / 1.384 GB, free: 13.22 MB / 1.123 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 0.001658/1.646, allocations: 1.007 MB / 1.385 GB, free: 12.2 MB / 1.123 GB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.005321/1.651, allocations: 3.167 MB / 1.389 GB, free: 8.91 MB / 1.123 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 7.895e-06/1.651, allocations: 0 / 1.389 GB, free: 8.91 MB / 1.123 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.001138/1.652, allocations: 231.7 kB / 1.389 GB, free: 8.684 MB / 1.123 GB Notification: Performance of postOpt tearingSystem (simulation): time 1.267e-05/1.652, allocations: 8 kB / 1.389 GB, free: 8.676 MB / 1.123 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 7.831e-05/1.653, allocations: 28.3 kB / 1.389 GB, free: 8.648 MB / 1.123 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 1.5e-05/1.653, allocations: 12 kB / 1.389 GB, free: 8.637 MB / 1.123 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 6.502e-06/1.653, allocations: 7.938 kB / 1.389 GB, free: 8.629 MB / 1.123 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.00317/1.656, allocations: 1.909 MB / 1.391 GB, free: 6.672 MB / 1.123 GB Notification: Performance of postOpt removeConstants (simulation): time 0.0008964/1.657, allocations: 358.9 kB / 1.391 GB, free: 6.301 MB / 1.123 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0002404/1.657, allocations: 32 kB / 1.391 GB, free: 6.27 MB / 1.123 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.001081/1.658, allocations: 36.91 kB / 1.391 GB, free: 6.234 MB / 1.123 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0002213/1.658, allocations: 80.81 kB / 1.391 GB, free: 6.152 MB / 1.123 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 9.072e-05/1.658, allocations: 39.98 kB / 1.391 GB, free: 6.113 MB / 1.123 GB Notification: Performance of sorting global known variables: time 0.001714/1.66, allocations: 0.8258 MB / 1.392 GB, free: 5.285 MB / 1.123 GB Notification: Performance of sort global known variables: time 1.3e-07/1.66, allocations: 0 / 1.392 GB, free: 5.285 MB / 1.123 GB Notification: Performance of remove unused functions: time 0.002904/1.663, allocations: 0.8338 MB / 1.393 GB, free: 4.449 MB / 1.123 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 11 * Number of states: 9 (roo.dynBal.medium.Xi[1],roo.dynBal.U,roo.dynBal.m,oriChiTop.mExc,oriBot.mExc,oriChiBot.mExc,sha.vol.dynBal.medium.Xi[1],sha.vol.dynBal.U,sha.vol.dynBal.m) * Number of discrete variables: 3 ($whenCondition1,mRoo_flow.nextTimeEvent,mRoo_flow.nextTimeEventScaled) * Number of discrete states: 2 (mRoo_flow.nextTimeEvent,mRoo_flow.nextTimeEventScaled) * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for simulation (110): * Single equations (assignments): 108 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 2 * If-equations: 0 * Equation systems (not torn): 0 * Torn equation systems: 0 * Mixed (continuous/discrete) equation systems: 0 Notification: Performance of Backend phase and start with SimCode phase: time 0.00193/1.665, allocations: 0.5731 MB / 1.393 GB, free: 4.035 MB / 1.123 GB Notification: Performance of simCode: created initialization part: time 0.003553/1.668, allocations: 1.62 MB / 1.395 GB, free: 2.422 MB / 1.123 GB Notification: Performance of simCode: created event and clocks part: time 1.263e-05/1.669, allocations: 4 kB / 1.395 GB, free: 2.418 MB / 1.123 GB Notification: Performance of simCode: created simulation system equations: time 0.001003/1.67, allocations: 0.5599 MB / 1.396 GB, free: 1.855 MB / 1.123 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.004686/1.674, allocations: 0.8836 MB / 1.396 GB, free: 0.9922 MB / 1.123 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.006698/1.681, allocations: 3.402 MB / 1.4 GB, free: 13.52 MB / 1.139 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.001321/1.682, allocations: 1.36 MB / 1.401 GB, free: 12.13 MB / 1.139 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0005886/1.683, allocations: 119.4 kB / 1.401 GB, free: 12.02 MB / 1.139 GB Notification: Performance of SimCode: time 5.159e-06/1.683, allocations: 0 / 1.401 GB, free: 12.02 MB / 1.139 GB Notification: Performance of Templates: time 0.04493/1.728, allocations: 25.44 MB / 1.426 GB, free: 2.758 MB / 1.154 GB make -j1 -f Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.makefile (rm -f Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.pipe ; mkfifo Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.pipe ; head -c 1048576 < Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.pipe >> ../files/Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.sim & ./Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume -abortSlowSimulation -alarm=480 -emit_protected -lv LOG_STATS > Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.pipe 2>&1) diffSimulationResults("Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume_res.mat","/mnt/ReferenceFiles/Buildings/csv/maint_9.1.x/Buildings_Airflow_Multizone_Examples_ChimneyShaftWithVolume.csv","/var/lib/jenkins1/ws/OpenModelicaLibraryTestingWork/OpenModelicaLibraryTesting/files/Buildings_9_Buildings.Airflow.Multizone.Examples.ChimneyShaftWithVolume.diff",relTol=0.003,relTolDiffMinMax=0.003,rangeDelta=0.001) Reference file matches