Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries --ompython_omhome=/usr Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.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 11.0.0-master/package.mo", uses=false) Using package Buildings with version 11.0.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 11.0.0-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: translateModel(Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5000,variableFilter="time|sin.ports.1..m_flow",fileNamePrefix="Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised") translateModel(Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5000,variableFilter="time|sin.ports.1..m_flow",fileNamePrefix="Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised") Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.001147/0.001147, allocations: 91.77 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 0.001563/0.001563, 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 4.0.0+maint.om/package.mo): time 1.359/1.359, allocations: 223.3 MB / 240 MB, free: 5.285 MB / 190.1 MB Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Buildings 11.0.0-master/package.mo): time 2.899/2.899, allocations: 462.6 MB / 0.736 GB, free: 15.73 MB / 0.5919 GB Notification: Performance of FrontEnd - loaded program: time 0.0003712/0.0003713, allocations: 10.03 kB / 0.9021 GB, free: 36.67 MB / 0.7169 GB Notification: Performance of FrontEnd - Absyn->SCode: time 0.3862/0.3866, allocations: 159.6 MB / 1.058 GB, free: 5.301 MB / 0.8106 GB Notification: Performance of NFInst.instantiate(Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised): time 0.1803/0.5669, allocations: 152.4 MB / 1.207 GB, free: 12.45 MB / 0.9669 GB Notification: Performance of NFInst.instExpressions: time 0.005604/0.5726, allocations: 3.793 MB / 1.211 GB, free: 8.648 MB / 0.9669 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.0003922/0.573, allocations: 19.88 kB / 1.211 GB, free: 8.629 MB / 0.9669 GB Notification: Performance of NFTyping.typeComponents: time 0.0006833/0.5737, allocations: 163 kB / 1.211 GB, free: 8.469 MB / 0.9669 GB Notification: Performance of NFTyping.typeBindings: time 0.001513/0.5752, allocations: 0.4937 MB / 1.211 GB, free: 7.973 MB / 0.9669 GB Notification: Performance of NFTyping.typeClassSections: time 0.001359/0.5766, allocations: 408.7 kB / 1.212 GB, free: 7.578 MB / 0.9669 GB Notification: Performance of NFFlatten.flatten: time 0.003458/0.5801, allocations: 3.266 MB / 1.215 GB, free: 4.305 MB / 0.9669 GB Notification: Performance of NFFlatten.resolveConnections: time 0.002858/0.5829, allocations: 2.293 MB / 1.217 GB, free: 2.004 MB / 0.9669 GB Notification: Performance of NFEvalConstants.evaluate: time 0.002468/0.5854, allocations: 1.07 MB / 1.218 GB, free: 0.9297 MB / 0.9669 GB Notification: Performance of NFSimplifyModel.simplify: time 0.001052/0.5865, allocations: 0.8443 MB / 1.219 GB, free: 84 kB / 0.9669 GB Notification: Performance of NFPackage.collectConstants: time 9.943e-05/0.5866, allocations: 48 kB / 1.219 GB, free: 36 kB / 0.9669 GB Notification: Performance of NFFlatten.collectFunctions: time 0.001407/0.588, allocations: 0.6003 MB / 1.22 GB, free: 15.43 MB / 0.9825 GB Notification: Performance of NFScalarize.scalarize: time 0.0003554/0.5884, allocations: 326.8 kB / 1.22 GB, free: 15.11 MB / 0.9825 GB Notification: Performance of NFVerifyModel.verify: time 0.0003633/0.5887, allocations: 249.1 kB / 1.22 GB, free: 14.86 MB / 0.9825 GB Notification: Performance of NFConvertDAE.convert: time 0.001291/0.59, allocations: 1.185 MB / 1.221 GB, free: 13.68 MB / 0.9825 GB Notification: Performance of FrontEnd - DAE generated: time 7.494e-06/0.5901, allocations: 0 / 1.221 GB, free: 13.68 MB / 0.9825 GB Notification: Performance of FrontEnd: time 1.854e-06/0.5901, allocations: 0 / 1.221 GB, free: 13.68 MB / 0.9825 GB Notification: Performance of Transformations before backend: time 1.242e-05/0.5901, allocations: 0 / 1.221 GB, free: 13.68 MB / 0.9825 GB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 135 * Number of variables: 135 Notification: Performance of Generate backend data structure: time 0.002456/0.5925, allocations: 1.511 MB / 1.223 GB, free: 12.1 MB / 0.9825 GB Notification: Performance of prepare preOptimizeDAE: time 3.773e-05/0.5926, allocations: 8.031 kB / 1.223 GB, free: 12.09 MB / 0.9825 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.0008169/0.5934, allocations: 198.4 kB / 1.223 GB, free: 11.9 MB / 0.9825 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.00144/0.5949, allocations: 0.8873 MB / 1.224 GB, free: 10.96 MB / 0.9825 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 4.43e-05/0.5949, allocations: 45.31 kB / 1.224 GB, free: 10.91 MB / 0.9825 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0001062/0.595, allocations: 64 kB / 1.224 GB, free: 10.85 MB / 0.9825 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.001487/0.5965, allocations: 0.987 MB / 1.225 GB, free: 9.785 MB / 0.9825 GB Notification: Performance of preOpt findStateOrder (simulation): time 1.75e-05/0.5966, allocations: 7.938 kB / 1.225 GB, free: 9.777 MB / 0.9825 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 6.804e-05/0.5966, allocations: 24 kB / 1.225 GB, free: 9.754 MB / 0.9825 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 1.4e-05/0.5966, allocations: 12 kB / 1.225 GB, free: 9.742 MB / 0.9825 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.001266/0.5979, allocations: 0.8038 MB / 1.226 GB, free: 8.934 MB / 0.9825 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 0.004457/0.6024, allocations: 4.812 MB / 1.23 GB, free: 3.777 MB / 0.9825 GB Notification: Performance of preOpt comSubExp (simulation): time 0.00242/0.6048, allocations: 4.018 MB / 1.234 GB, free: 14.93 MB / 0.9981 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.0005068/0.6053, allocations: 353.2 kB / 1.235 GB, free: 14.59 MB / 0.9981 GB Notification: Performance of preOpt evalFunc (simulation): time 0.0003023/0.6057, allocations: 198.4 kB / 1.235 GB, free: 14.36 MB / 0.9981 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 0.0005385/0.6062, allocations: 332.9 kB / 1.235 GB, free: 14.01 MB / 0.9981 GB Notification: Performance of preOpt simplifyInStream (simulation): time 0.0003032/0.6065, allocations: 27.69 kB / 1.235 GB, free: 13.98 MB / 0.9981 GB Notification: Performance of pre-optimization done (n=35): time 2.775e-06/0.6065, allocations: 0 / 1.235 GB, free: 13.98 MB / 0.9981 GB Notification: Performance of matching and sorting (n=35): time 0.004914/0.6115, allocations: 1.767 MB / 1.237 GB, free: 12.19 MB / 0.9981 GB Notification: Performance of inlineWhenForInitialization (initialization): time 5.194e-05/0.6115, allocations: 85.11 kB / 1.237 GB, free: 12.09 MB / 0.9981 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.001496/0.613, allocations: 1.177 MB / 1.238 GB, free: 10.89 MB / 0.9981 GB Notification: Performance of collectPreVariables (initialization): time 4.915e-05/0.6131, allocations: 37.7 kB / 1.238 GB, free: 10.85 MB / 0.9981 GB Notification: Performance of collectInitialEqns (initialization): time 0.0004405/0.6135, allocations: 0.5121 MB / 1.239 GB, free: 10.34 MB / 0.9981 GB Notification: Performance of collectInitialBindings (initialization): time 0.0001115/0.6137, allocations: 122.3 kB / 1.239 GB, free: 10.21 MB / 0.9981 GB Notification: Performance of simplifyInitialFunctions (initialization): time 2.693e-05/0.6137, allocations: 8 kB / 1.239 GB, free: 10.21 MB / 0.9981 GB Notification: Performance of setup shared object (initialization): time 0.0001225/0.6138, allocations: 322 kB / 1.239 GB, free: 9.887 MB / 0.9981 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.0003693/0.6142, allocations: 217 kB / 1.239 GB, free: 9.672 MB / 0.9981 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.0006247/0.6148, allocations: 0.5331 MB / 1.24 GB, free: 9.004 MB / 0.9981 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.0004606/0.6153, allocations: 321.4 kB / 1.24 GB, free: 8.684 MB / 0.9981 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 5.932e-06/0.6153, allocations: 4 kB / 1.24 GB, free: 8.68 MB / 0.9981 GB Notification: Performance of matching and sorting (n=58) (initialization): time 0.002154/0.6175, allocations: 1.068 MB / 1.241 GB, free: 7.594 MB / 0.9981 GB Notification: Performance of prepare postOptimizeDAE: time 0.0001784/0.6177, allocations: 271.5 kB / 1.241 GB, free: 7.246 MB / 0.9981 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.33e-05/0.6177, allocations: 8 kB / 1.241 GB, free: 7.238 MB / 0.9981 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.001281/0.619, allocations: 382.1 kB / 1.242 GB, free: 6.863 MB / 0.9981 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0002913/0.6193, allocations: 67.89 kB / 1.242 GB, free: 6.797 MB / 0.9981 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.001049/0.6203, allocations: 1.065 MB / 1.243 GB, free: 5.707 MB / 0.9981 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.0008598/0.6212, allocations: 103.7 kB / 1.243 GB, free: 5.605 MB / 0.9981 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 5.704e-05/0.6213, allocations: 24 kB / 1.243 GB, free: 5.582 MB / 0.9981 GB Notification: Performance of prepare postOptimizeDAE: time 7.965e-06/0.6213, allocations: 7.938 kB / 1.243 GB, free: 5.574 MB / 0.9981 GB Notification: Performance of postOpt replaceHomotopyWithSimplified (initialization): time 0.001391/0.6227, allocations: 0.81 MB / 1.244 GB, free: 4.754 MB / 0.9981 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 6.362e-06/0.6227, allocations: 4.625 kB / 1.244 GB, free: 4.75 MB / 0.9981 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.0005777/0.6233, allocations: 271.3 kB / 1.244 GB, free: 4.484 MB / 0.9981 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0002911/0.6236, allocations: 75.89 kB / 1.244 GB, free: 4.41 MB / 0.9981 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.003673/0.6273, allocations: 3.139 MB / 1.247 GB, free: 1.137 MB / 0.9981 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.0008632/0.6282, allocations: 103.8 kB / 1.247 GB, free: 1.035 MB / 0.9981 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 3.964e-05/0.6282, allocations: 20 kB / 1.247 GB, free: 1.016 MB / 0.9981 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 24 * Number of states: 0 () * Number of discrete variables: 5 ($whenCondition1,$PRE.pulse_m_flow.T_start,pulse_m_flow.T_start,$PRE.pulse_m_flow.count,pulse_m_flow.count) * Number of discrete states: 0 () * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for initialization (35): * Single equations (assignments): 33 * Array equations: 0 * Algorithm blocks: 1 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 1 {1 22} Notification: Performance of prepare postOptimizeDAE: time 0.0005962/0.6288, allocations: 472.7 kB / 1.248 GB, free: 0.543 MB / 0.9981 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0001284/0.6289, allocations: 118.6 kB / 1.248 GB, free: 436 kB / 0.9981 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.682/1.311, allocations: 0.8035 MB / 1.249 GB, free: 191.1 MB / 0.9981 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 1.589e-05/1.311, allocations: 4.906 kB / 1.249 GB, free: 191.1 MB / 0.9981 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 5.641e-06/1.311, allocations: 2.391 kB / 1.249 GB, free: 191.1 MB / 0.9981 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 9.367e-06/1.311, allocations: 1.688 kB / 1.249 GB, free: 191.1 MB / 0.9981 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 0.004223/1.315, allocations: 2.17 MB / 1.251 GB, free: 190.3 MB / 0.9981 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 6.833e-06/1.315, allocations: 1.938 kB / 1.251 GB, free: 190.3 MB / 0.9981 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.0002548/1.316, allocations: 54.95 kB / 1.251 GB, free: 190.3 MB / 0.9981 GB Notification: Performance of postOpt tearingSystem (simulation): time 0.0004865/1.316, allocations: 211.3 kB / 1.251 GB, free: 190.3 MB / 0.9981 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 3.367e-05/1.316, allocations: 7.812 kB / 1.251 GB, free: 190.3 MB / 0.9981 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.0007268/1.317, allocations: 0.8849 MB / 1.252 GB, free: 189.8 MB / 0.9981 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 5.721e-06/1.317, allocations: 1.906 kB / 1.252 GB, free: 189.8 MB / 0.9981 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.001511/1.318, allocations: 0.8871 MB / 1.253 GB, free: 189.5 MB / 0.9981 GB Notification: Performance of postOpt removeConstants (simulation): time 0.0005594/1.319, allocations: 240.4 kB / 1.253 GB, free: 189.4 MB / 0.9981 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0002755/1.319, allocations: 7.656 kB / 1.253 GB, free: 189.4 MB / 0.9981 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.0008273/1.32, allocations: 73.58 kB / 1.253 GB, free: 189.4 MB / 0.9981 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0001208/1.32, allocations: 38.58 kB / 1.253 GB, free: 189.4 MB / 0.9981 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 3.658e-05/1.32, allocations: 15.97 kB / 1.253 GB, free: 189.4 MB / 0.9981 GB Notification: Performance of sorting global known variables: time 0.001652/1.322, allocations: 0.8292 MB / 1.254 GB, free: 189.3 MB / 0.9981 GB Notification: Performance of sort global known variables: time 1.31e-07/1.322, allocations: 0 / 1.254 GB, free: 189.3 MB / 0.9981 GB Notification: Performance of remove unused functions: time 0.002332/1.324, allocations: 0.5086 MB / 1.254 GB, free: 189.3 MB / 0.9981 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 8 * Number of states: 0 () * Number of discrete variables: 3 ($whenCondition1,pulse_m_flow.T_start,pulse_m_flow.count) * Number of discrete states: 1 (pulse_m_flow.count) * Number of clocked states: 0 () * Top-level inputs: 0 Notification: Strong component statistics for simulation (22): * Single equations (assignments): 19 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 2 * If-equations: 0 * Equation systems (linear and non-linear blocks): 0 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Torn system details for strict tearing set: * Linear torn systems: 0 * Non-linear torn systems: 1 {1 13} Notification: Performance of Backend phase and start with SimCode phase: time 0.000501/1.325, allocations: 180.3 kB / 1.255 GB, free: 189.2 MB / 0.9981 GB Notification: Performance of simCode: created initialization part: time 0.002026/1.327, allocations: 1.138 MB / 1.256 GB, free: 188.9 MB / 0.9981 GB Notification: Performance of simCode: created event and clocks part: time 5.28e-06/1.327, allocations: 6.031 kB / 1.256 GB, free: 188.9 MB / 0.9981 GB Notification: Performance of simCode: created simulation system equations: time 0.0004676/1.327, allocations: 251.2 kB / 1.256 GB, free: 188.9 MB / 0.9981 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.003357/1.331, allocations: 0.6591 MB / 1.257 GB, free: 188.9 MB / 0.9981 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.003473/1.334, allocations: 2.11 MB / 1.259 GB, free: 188 MB / 0.9981 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.0009356/1.335, allocations: 1.212 MB / 1.26 GB, free: 187.3 MB / 0.9981 GB Notification: Performance of simCode: alias equations: time 0.00127/1.336, allocations: 327.9 kB / 1.26 GB, free: 187.2 MB / 0.9981 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0001794/1.337, allocations: 68.64 kB / 1.26 GB, free: 187.2 MB / 0.9981 GB Notification: Performance of SimCode: time 8.61e-07/1.337, allocations: 0 / 1.26 GB, free: 187.2 MB / 0.9981 GB Notification: Performance of Templates: time 0.04582/1.382, allocations: 21.13 MB / 1.281 GB, free: 180.7 MB / 0.9981 GB make -j1 -f Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.makefile (rm -f Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.pipe ; mkfifo Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.pipe ; head -c 1048576 < Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.pipe >> ../files/Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.sim & ./Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised -abortSlowSimulation -alarm=480 -emit_protected -lv LOG_STATS > Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.pipe 2>&1) diffSimulationResults("Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised_res.mat","/mnt/ReferenceFiles/Buildings/csv/master/Buildings_Fluid_Examples_Performance_PressureDrop_SeriesParallelDpOptimised.csv","/var/lib/jenkins/ws/OpenModelicaLibraryTestingWork/OpenModelicaLibraryTesting/files/Buildings_latest_Buildings.Fluid.Examples.Performance.PressureDrop.SeriesParallelDpOptimised.diff",relTol=0.003,relTolDiffMinMax=0.003,rangeDelta=0.001) Reference file matches