Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries --ompython_omhome=/usr ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.conf.json loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices trunk/package.mo", uses=false) [Timeout 90] Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices trunk/package.mo): time 0.001495/0.001495, allocations: 108.9 kB / 20.37 MB, free: 2.102 MB / 14.72 MB [Timeout remaining time 90] loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex trunk/package.mo", uses=false) [Timeout 90] Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex trunk/package.mo): time 0.001666/0.001666, allocations: 212.2 kB / 23.54 MB, free: 5.402 MB / 14.72 MB [Timeout remaining time 90] loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica trunk/package.mo", uses=false) [Timeout 90] Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica trunk/package.mo): time 1.434/1.434, allocations: 230.2 MB / 256.7 MB, free: 8.652 MB / 206.1 MB [Timeout remaining time 88] loadFile("/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaTest 4.1.0-beta.om/package.mo", uses=false) [Timeout 90] Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaTest 4.1.0-beta.om/package.mo): time 0.2208/0.2208, allocations: 46.89 MB / 359.9 MB, free: 5.039 MB / 286.1 MB [Timeout remaining time 90] Using package ModelicaTest with version 4.1.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaTest 4.1.0-beta.om/package.mo) Using package Modelica with version trunk (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica trunk/package.mo) Using package Complex with version trunk (/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex trunk/package.mo) Using package ModelicaServices with version trunk (/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices trunk/package.mo) Running command: translateModel(ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5002,variableFilter="time|volume.medium.p|volume.medium.T|volume.medium.X.1.|volume.medium.X.2.|volume.medium.X.3.|volume.medium.X.4.|volume.medium.X.5.|volume.medium.X.6.",fileNamePrefix="ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas") translateModel(ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5002,variableFilter="time|volume.medium.p|volume.medium.T|volume.medium.X.1.|volume.medium.X.2.|volume.medium.X.3.|volume.medium.X.4.|volume.medium.X.5.|volume.medium.X.6.",fileNamePrefix="ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas") [Timeout 660] Warning: Requested package Modelica of version 4.1.0, but this package was already loaded with version trunk. OpenModelica cannot reason about compatibility between the two packages since they are not semantic versions. Notification: Performance of FrontEnd - loaded program: time 0.002312/0.002312, allocations: 79.88 kB / 0.495 GB, free: 8.738 MB / 366.1 MB Notification: Performance of FrontEnd - Absyn->SCode: time 0.3632/0.3655, allocations: 65.98 MB / 0.5594 GB, free: 5.242 MB / 398.1 MB Notification: Performance of NFInst.instantiate(ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas): time 0.5363/0.9018, allocations: 180.6 MB / 0.7358 GB, free: 1.793 MB / 0.5606 GB Notification: Performance of NFInst.instExpressions: time 0.008896/0.9107, allocations: 6.519 MB / 0.7422 GB, free: 1.781 MB / 0.5606 GB Notification: Performance of NFInst.updateImplicitVariability: time 0.0007055/0.9114, allocations: 22.06 kB / 0.7422 GB, free: 1.781 MB / 0.5606 GB Notification: Performance of NFTyping.typeComponents: time 0.001128/0.9126, allocations: 449.5 kB / 0.7426 GB, free: 1.773 MB / 0.5606 GB Notification: Performance of NFTyping.typeBindings: time 0.003903/0.9165, allocations: 1.788 MB / 0.7444 GB, free: 1.707 MB / 0.5606 GB Notification: Performance of NFTyping.typeClassSections: time 0.003609/0.9201, allocations: 1.532 MB / 0.7458 GB, free: 1.656 MB / 0.5606 GB Notification: Performance of NFFlatten.flatten: time 0.002193/0.9223, allocations: 2.248 MB / 0.748 GB, free: 1.645 MB / 0.5606 GB Notification: Performance of NFFlatten.resolveConnections: time 0.0008363/0.9231, allocations: 0.6681 MB / 0.7487 GB, free: 1.625 MB / 0.5606 GB Notification: Performance of NFEvalConstants.evaluate: time 0.003488/0.9266, allocations: 1.82 MB / 0.7505 GB, free: 1.605 MB / 0.5606 GB Notification: Performance of NFSimplifyModel.simplify: time 0.002535/0.9291, allocations: 1.685 MB / 0.7521 GB, free: 1.59 MB / 0.5606 GB Notification: Performance of NFPackage.collectConstants: time 0.0002126/0.9293, allocations: 100.7 kB / 0.7522 GB, free: 1.59 MB / 0.5606 GB Notification: Performance of NFFlatten.collectFunctions: time 0.002763/0.9321, allocations: 1.388 MB / 0.7536 GB, free: 1.574 MB / 0.5606 GB Notification: Performance of NFScalarize.scalarize: time 0.0005749/0.9327, allocations: 0.7001 MB / 0.7543 GB, free: 1.57 MB / 0.5606 GB Notification: Performance of NFVerifyModel.verify: time 0.0008003/0.9335, allocations: 0.7532 MB / 0.755 GB, free: 1.57 MB / 0.5606 GB Notification: Performance of NFConvertDAE.convert: time 0.003144/0.9366, allocations: 2.629 MB / 0.7576 GB, free: 1.441 MB / 0.5606 GB Notification: Performance of FrontEnd - DAE generated: time 4.849e-06/0.9366, allocations: 5.75 kB / 0.7576 GB, free: 1.441 MB / 0.5606 GB Notification: Performance of FrontEnd: time 1.552e-06/0.9366, allocations: 0 / 0.7576 GB, free: 1.441 MB / 0.5606 GB Notification: Performance of Transformations before backend: time 2.607e-05/0.9367, allocations: 1.094 kB / 0.7576 GB, free: 1.441 MB / 0.5606 GB Notification: Model statistics after passing the front-end and creating the data structures used by the back-end: * Number of equations: 276 * Number of variables: 276 Notification: Performance of Generate backend data structure: time 0.003255/0.9399, allocations: 1.748 MB / 0.7593 GB, free: 16.62 MB / 0.5762 GB Notification: Performance of prepare preOptimizeDAE: time 3.534e-05/0.9399, allocations: 8.156 kB / 0.7593 GB, free: 16.62 MB / 0.5762 GB Notification: Performance of preOpt normalInlineFunction (simulation): time 0.001378/0.9413, allocations: 313.4 kB / 0.7596 GB, free: 16.56 MB / 0.5762 GB Notification: Performance of preOpt evaluateParameters (simulation): time 0.001351/0.9427, allocations: 0.7768 MB / 0.7603 GB, free: 16.26 MB / 0.5762 GB Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.0001256/0.9428, allocations: 142.7 kB / 0.7605 GB, free: 16.2 MB / 0.5762 GB Notification: Performance of preOpt expandDerOperator (simulation): time 0.0001622/0.943, allocations: 107.3 kB / 0.7606 GB, free: 16.2 MB / 0.5762 GB Notification: Performance of preOpt clockPartitioning (simulation): time 0.002349/0.9453, allocations: 1.838 MB / 0.7624 GB, free: 16 MB / 0.5762 GB Notification: Performance of preOpt findStateOrder (simulation): time 3.308e-05/0.9453, allocations: 13.31 kB / 0.7624 GB, free: 15.99 MB / 0.5762 GB Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.0001398/0.9455, allocations: 48.14 kB / 0.7624 GB, free: 15.99 MB / 0.5762 GB Notification: Performance of preOpt inlineArrayEqn (simulation): time 9.595e-05/0.9456, allocations: 94.53 kB / 0.7625 GB, free: 15.98 MB / 0.5762 GB Notification: Performance of preOpt removeEqualRHS (simulation): time 0.002216/0.9478, allocations: 1.701 MB / 0.7642 GB, free: 15.98 MB / 0.5762 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 0.009061/0.9569, allocations: 6.854 MB / 0.7709 GB, free: 12.49 MB / 0.5762 GB Notification: Performance of preOpt comSubExp (simulation): time 0.001188/0.958, allocations: 0.8509 MB / 0.7717 GB, free: 12.47 MB / 0.5762 GB Notification: Performance of preOpt resolveLoops (simulation): time 0.000559/0.9586, allocations: 438.7 kB / 0.7721 GB, free: 12.46 MB / 0.5762 GB Notification: Performance of preOpt evalFunc (simulation): time 0.0001392/0.9587, allocations: 105.8 kB / 0.7722 GB, free: 12.36 MB / 0.5762 GB Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 5.342e-05/0.9588, allocations: 45.34 kB / 0.7723 GB, free: 12.32 MB / 0.5762 GB Notification: Performance of pre-optimization done (n=60): time 3.156e-06/0.9588, allocations: 1.984 kB / 0.7723 GB, free: 12.32 MB / 0.5762 GB Notification: Performance of matching and sorting (n=72): time 0.0105/0.9693, allocations: 4.132 MB / 0.7763 GB, free: 11.55 MB / 0.5762 GB Notification: Performance of inlineWhenForInitialization (initialization): time 8.456e-05/0.9694, allocations: 111.4 kB / 0.7764 GB, free: 11.42 MB / 0.5762 GB Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.001257/0.9706, allocations: 1.106 MB / 0.7775 GB, free: 11.27 MB / 0.5762 GB Notification: Performance of collectPreVariables (initialization): time 0.0001148/0.9708, allocations: 43.2 kB / 0.7775 GB, free: 11.23 MB / 0.5762 GB Notification: Performance of collectInitialEqns (initialization): time 0.0003617/0.9711, allocations: 0.5328 MB / 0.7781 GB, free: 10.99 MB / 0.5762 GB Notification: Performance of collectInitialBindings (initialization): time 0.0002296/0.9713, allocations: 281.3 kB / 0.7783 GB, free: 10.82 MB / 0.5762 GB Notification: Performance of simplifyInitialFunctions (initialization): time 0.0003332/0.9717, allocations: 214.8 kB / 0.7785 GB, free: 10.79 MB / 0.5762 GB Notification: Performance of setup shared object (initialization): time 0.0001749/0.9719, allocations: 345.6 kB / 0.7789 GB, free: 10.49 MB / 0.5762 GB Notification: Performance of preBalanceInitialSystem (initialization): time 0.0007942/0.9726, allocations: 0.5829 MB / 0.7794 GB, free: 10.49 MB / 0.5762 GB Notification: Performance of partitionIndependentBlocks (initialization): time 0.001017/0.9737, allocations: 0.878 MB / 0.7803 GB, free: 10.17 MB / 0.5762 GB Notification: Performance of analyzeInitialSystem (initialization): time 0.002087/0.9758, allocations: 1.447 MB / 0.7817 GB, free: 9.867 MB / 0.5762 GB Notification: Performance of solveInitialSystemEqSystem (initialization): time 5.591e-06/0.9758, allocations: 4.344 kB / 0.7817 GB, free: 9.867 MB / 0.5762 GB Notification: Performance of matching and sorting (n=125) (initialization): time 0.003132/0.9789, allocations: 1.982 MB / 0.7836 GB, free: 9.742 MB / 0.5762 GB Notification: Performance of prepare postOptimizeDAE: time 2.173e-05/0.9789, allocations: 7.656 kB / 0.7836 GB, free: 9.742 MB / 0.5762 GB Notification: Performance of postOpt simplifyComplexFunction (initialization): time 1.361e-05/0.9789, allocations: 9.312 kB / 0.7836 GB, free: 9.742 MB / 0.5762 GB Notification: Performance of postOpt tearingSystem (initialization): time 0.0044/0.9833, allocations: 1.352 MB / 0.785 GB, free: 9.711 MB / 0.5762 GB Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.0005813/0.9839, allocations: 146.4 kB / 0.7851 GB, free: 9.711 MB / 0.5762 GB Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.002564/0.9865, allocations: 1.925 MB / 0.787 GB, free: 9.164 MB / 0.5762 GB Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.0009687/0.9874, allocations: 45.19 kB / 0.787 GB, free: 9.164 MB / 0.5762 GB Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.0001085/0.9875, allocations: 69.16 kB / 0.7871 GB, free: 9.164 MB / 0.5762 GB Notification: Model statistics after passing the back-end for initialization: * Number of independent subsystems: 37 * Number of states: 0 () * Number of discrete variables: 4 (volume.regularFlow[1],volume.regularFlow[2],volume.inFlow[2],volume.inFlow[1]) * 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 {(9,35)} Notification: Performance of prepare postOptimizeDAE: time 0.0006502/0.9882, allocations: 401.2 kB / 0.7875 GB, free: 9.043 MB / 0.5762 GB Notification: Performance of postOpt lateInlineFunction (simulation): time 0.0002379/0.9884, allocations: 114.3 kB / 0.7876 GB, free: 8.988 MB / 0.5762 GB Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.002494/0.9909, allocations: 1.494 MB / 0.789 GB, free: 8.906 MB / 0.5762 GB Notification: Performance of postOpt inlineArrayEqn (simulation): time 7.574e-06/0.9909, allocations: 7.812 kB / 0.7891 GB, free: 8.906 MB / 0.5762 GB Notification: Performance of postOpt constantLinearSystem (simulation): time 1.044e-05/0.9909, allocations: 7.375 kB / 0.7891 GB, free: 8.902 MB / 0.5762 GB Notification: Performance of postOpt simplifysemiLinear (simulation): time 8.806e-06/0.991, allocations: 3.078 kB / 0.7891 GB, free: 8.902 MB / 0.5762 GB Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.003851/0.9948, allocations: 2.697 MB / 0.7917 GB, free: 8.543 MB / 0.5762 GB Notification: Performance of postOpt simplifyComplexFunction (simulation): time 3.967e-06/0.9948, allocations: 0 / 0.7917 GB, free: 8.543 MB / 0.5762 GB Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.001722/0.9965, allocations: 323.4 kB / 0.792 GB, free: 8.543 MB / 0.5762 GB Notification: Performance of postOpt tearingSystem (simulation): time 0.0001779/0.9967, allocations: 67.42 kB / 0.7921 GB, free: 8.535 MB / 0.5762 GB Notification: Performance of postOpt inputDerivativesUsed (simulation): time 7.391e-05/0.9968, allocations: 34.77 kB / 0.7921 GB, free: 8.535 MB / 0.5762 GB Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.002641/0.9994, allocations: 3.034 MB / 0.7951 GB, free: 5.777 MB / 0.5762 GB Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 4.178e-06/0.9994, allocations: 5.375 kB / 0.7951 GB, free: 5.773 MB / 0.5762 GB Notification: Performance of postOpt symbolicJacobian (simulation): time 0.002736/1.002, allocations: 1.918 MB / 0.7969 GB, free: 5.535 MB / 0.5762 GB Notification: Performance of postOpt removeConstants (simulation): time 0.0006971/1.003, allocations: 340.5 kB / 0.7973 GB, free: 5.375 MB / 0.5762 GB Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.0001775/1.003, allocations: 31.14 kB / 0.7973 GB, free: 5.375 MB / 0.5762 GB Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.0008923/1.004, allocations: 50.81 kB / 0.7973 GB, free: 5.375 MB / 0.5762 GB Notification: Performance of postOpt findZeroCrossings (simulation): time 0.0001477/1.004, allocations: 61.16 kB / 0.7974 GB, free: 5.375 MB / 0.5762 GB Notification: Performance of postOpt collapseArrayExpressions (simulation): time 0.0001061/1.004, allocations: 60.38 kB / 0.7975 GB, free: 5.371 MB / 0.5762 GB Notification: Performance of sorting global known variables: time 0.0009633/1.005, allocations: 0.7964 MB / 0.7982 GB, free: 5.137 MB / 0.5762 GB Notification: Performance of sort global known variables: time 9e-08/1.005, allocations: 0 / 0.7982 GB, free: 5.137 MB / 0.5762 GB Notification: Performance of remove unused functions: time 0.001389/1.007, allocations: 484.6 kB / 0.7987 GB, free: 5.098 MB / 0.5762 GB Notification: Model statistics after passing the back-end for simulation: * Number of independent subsystems: 2 * Number of states: 8 (volume.medium.p,volume.medium.Xi[1],volume.medium.Xi[2],volume.medium.Xi[3],volume.medium.Xi[4],volume.medium.Xi[5],volume.medium.Xi[6],volume.medium.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 (78): * Single equations (assignments): 76 * Array equations: 0 * Algorithm blocks: 0 * Record equations: 0 * When equations: 0 * If-equations: 0 * Equation systems (not torn): 1 * Torn equation systems: 1 * Mixed (continuous/discrete) equation systems: 0 Notification: Equation system details (not torn): * Constant Jacobian (size): 0 systems * Linear Jacobian (size,density): 0 systems * Non-linear Jacobian (size): 1 system {1} * Without analytic Jacobian (size): 0 systems Notification: Torn system details for strict tearing set: * Linear torn systems (#iteration vars, #inner vars, density): 1 system {(1,1,100.0%)} * Non-linear torn systems (#iteration vars, #inner vars): 0 systems Notification: Performance of Backend phase and start with SimCode phase: time 0.001722/1.008, allocations: 0.6765 MB / 0.7994 GB, free: 4.832 MB / 0.5762 GB Notification: Performance of simCode: created initialization part: time 0.002732/1.011, allocations: 1.42 MB / 0.8008 GB, free: 3.816 MB / 0.5762 GB Notification: Performance of simCode: created event and clocks part: time 7.103e-06/1.011, allocations: 4.656 kB / 0.8008 GB, free: 3.812 MB / 0.5762 GB Notification: Performance of simCode: created simulation system equations: time 0.001657/1.013, allocations: 0.8336 MB / 0.8016 GB, free: 3.18 MB / 0.5762 GB Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.003146/1.016, allocations: 0.7581 MB / 0.8023 GB, free: 2.523 MB / 0.5762 GB Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.005762/1.022, allocations: 3.045 MB / 0.8053 GB, free: 15.79 MB / 0.5919 GB Notification: Performance of simCode: some other stuff during SimCode phase: time 0.0009874/1.023, allocations: 1.171 MB / 0.8064 GB, free: 14.65 MB / 0.5919 GB Notification: Performance of simCode: all other stuff during SimCode phase: time 0.0004661/1.023, allocations: 118.2 kB / 0.8065 GB, free: 14.54 MB / 0.5919 GB Notification: Performance of SimCode: time 9.82e-07/1.023, allocations: 0 / 0.8065 GB, free: 14.54 MB / 0.5919 GB Notification: Performance of Templates: time 0.0484/1.071, allocations: 32.11 MB / 0.8379 GB, free: 14.69 MB / 0.6231 GB [Timeout remaining time 659] make -j1 -f ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.makefile [Timeout 660] (rm -f ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.pipe ; mkfifo ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.pipe ; head -c 1048576 < ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.pipe >> ../files/ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.sim & ./ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas -abortSlowSimulation -alarm=480 -emit_protected -lv LOG_STATS > ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.pipe 2>&1) [Timeout 480] diffSimulationResults("ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas_res.mat","/var/lib/jenkins1/ws/OpenModelicaLibraryTestingWork/Reference-modelica.org/ReferenceResults/MAP-LIB_ReferenceResults/v4.1.0/ModelicaTest/Media/TestsWithFluid/MediaTestModels/IdealGases/SimpleNaturalGas/SimpleNaturalGas.csv","/var/lib/jenkins1/ws/OpenModelicaLibraryTestingWork/OpenModelicaLibraryTesting/files/ModelicaTest_4.1.0-beta.om_ModelicaTest.Media.TestsWithFluid.MediaTestModels.IdealGases.SimpleNaturalGas.diff",relTol=0.003,relTolDiffMinMax=0.003,rangeDelta=0.001) [Timeout 660] [Timeout remaining time 660] Reference file matches