Running: ./testmodel.py --libraries=/home/hudson/saved_omc/libraries/.openmodelica/libraries/ --ompython_omhome=/usr Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.conf.json
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/ModelicaServices 4.0.0+maint.om/package.mo", uses=false)
Using package ModelicaServices with version 4.0.0 (/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/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)
Running command: translateModel(Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5000,variableFilter="time|inertia.phi|inertia.w",fileNamePrefix="Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic")
translateModel(Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic,tolerance=1e-06,outputFormat="mat",numberOfIntervals=5000,variableFilter="time|inertia.phi|inertia.w",fileNamePrefix="Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic")
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Complex 4.0.0+maint.om/package.mo): time 0.001202/0.001202, allocations: 186.5 kB / 17.27 MB, free: 4.504 MB / 13.93 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/Modelica 4.0.0+maint.om/package.mo): time 1.508/1.508, allocations: 222.9 MB / 240.9 MB, free: 10.99 MB / 202.7 MB
Notification: Performance of loadFile(/home/hudson/saved_omc/libraries/.openmodelica/libraries/ModelicaServices 4.0.0+maint.om/package.mo): time 0.0009942/0.0009941, allocations: 104.4 kB / 291.2 MB, free: 10.95 MB / 234.7 MB
Notification: Performance of FrontEnd - loaded program: time 0.0008972/0.0008975, allocations: 39.94 kB / 350 MB, free: 80 kB / 282.7 MB
Notification: Performance of FrontEnd - Absyn->SCode: time 0.243/0.2439, allocations: 49.43 MB / 399.5 MB, free: 33.37 MB / 298.7 MB
Notification: Performance of NFInst.instantiate(Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic): time 0.3492/0.5931, allocations: 114.2 MB / 0.5017 GB, free: 260 kB / 378.7 MB
Notification: Performance of NFInst.instExpressions: time 0.05947/0.6527, allocations: 22.39 MB / 0.5235 GB, free: 13.82 MB / 394.7 MB
Notification: Performance of NFInst.updateImplicitVariability: time 0.02723/0.6799, allocations: 0.5135 MB / 0.524 GB, free: 13.82 MB / 394.7 MB
Notification: Performance of NFTyping.typeComponents: time 0.0142/0.6942, allocations: 7.982 MB / 0.5318 GB, free: 11.97 MB / 394.7 MB
Notification: Performance of NFTyping.typeBindings: time 0.0118/0.7061, allocations: 3.404 MB / 0.5352 GB, free: 10.29 MB / 394.7 MB
Notification: Performance of NFTyping.typeClassSections: time 0.005994/0.7121, allocations: 1.851 MB / 0.537 GB, free: 9.152 MB / 394.7 MB
Notification: Performance of NFFlatten.flatten: time 0.02647/0.7386, allocations: 18.86 MB / 0.5554 GB, free: 14.2 MB / 410.7 MB
Notification: Performance of NFFlatten.resolveConnections: time 0.01749/0.7562, allocations: 10.15 MB / 0.5653 GB, free: 4.168 MB / 410.7 MB
Notification: Performance of NFEvalConstants.evaluate: time 0.009633/0.7658, allocations: 3.76 MB / 0.569 GB, free: 0.6055 MB / 410.7 MB
Notification: Performance of NFSimplifyModel.simplify: time 0.01103/0.7769, allocations: 5.993 MB / 0.5748 GB, free: 10.92 MB / 426.7 MB
Notification: Performance of NFPackage.collectConstants: time 0.003458/0.7804, allocations: 0.6289 MB / 0.5754 GB, free: 10.29 MB / 426.7 MB
Notification: Performance of NFFlatten.collectFunctions: time 0.006857/0.7873, allocations: 1.879 MB / 0.5773 GB, free: 8.473 MB / 426.7 MB
Notification: Performance of NFScalarize.scalarize: time 0.008133/0.7955, allocations: 4.71 MB / 0.5819 GB, free: 3.773 MB / 426.7 MB
Notification: Performance of NFVerifyModel.verify: time 0.01271/0.8082, allocations: 5.029 MB / 0.5868 GB, free: 14.73 MB / 442.7 MB
Notification: Performance of NFConvertDAE.convert: time 0.0223/0.8306, allocations: 16.63 MB / 0.603 GB, free: 14.43 MB / 458.7 MB
Notification: Performance of FrontEnd - DAE generated: time 8.085e-06/0.8306, allocations: 0 / 0.603 GB, free: 14.43 MB / 458.7 MB
Notification: Performance of FrontEnd: time 2.094e-06/0.8306, allocations: 0 / 0.603 GB, free: 14.43 MB / 458.7 MB
Notification: Performance of Transformations before backend: time 0.0007345/0.8314, allocations: 0 / 0.603 GB, free: 14.43 MB / 458.7 MB
Notification: Model statistics after passing the front-end and creating the data structures used by the back-end:
 * Number of equations: 2753
 * Number of variables: 2753
Notification: Performance of Generate backend data structure: time 0.03662/0.868, allocations: 11.21 MB / 0.614 GB, free: 3.27 MB / 458.7 MB
Notification: Performance of prepare preOptimizeDAE: time 5.095e-05/0.8681, allocations: 8.031 kB / 0.614 GB, free: 3.262 MB / 458.7 MB
Notification: Performance of preOpt normalInlineFunction (simulation): time 0.0466/0.9147, allocations: 5.417 MB / 0.6193 GB, free: 13.82 MB / 474.7 MB
Notification: Performance of preOpt evaluateParameters (simulation): time 0.02321/0.938, allocations: 8.855 MB / 0.6279 GB, free: 4.984 MB / 474.7 MB
Notification: Performance of preOpt simplifyIfEquations (simulation): time 0.000584/0.9386, allocations: 0.5195 MB / 0.6284 GB, free: 4.512 MB / 474.7 MB
Notification: Performance of preOpt expandDerOperator (simulation): time 0.003398/0.942, allocations: 0.7244 MB / 0.6291 GB, free: 3.836 MB / 474.7 MB
Notification: Performance of preOpt clockPartitioning (simulation): time 0.04493/0.987, allocations: 19.52 MB / 0.6482 GB, free: 15.41 MB / 0.4948 GB
Notification: Performance of preOpt findStateOrder (simulation): time 0.0005079/0.9875, allocations: 87.22 kB / 0.6483 GB, free: 15.33 MB / 0.4948 GB
Notification: Performance of preOpt replaceEdgeChange (simulation): time 0.002667/0.9902, allocations: 325.1 kB / 0.6486 GB, free: 15.06 MB / 0.4948 GB
Notification: Performance of preOpt inlineArrayEqn (simulation): time 0.004571/0.9948, allocations: 2.825 MB / 0.6513 GB, free: 12.25 MB / 0.4948 GB
Notification: Performance of preOpt removeEqualRHS (simulation): time 0.03823/1.033, allocations: 16.25 MB / 0.6672 GB, free: 11.98 MB / 0.5105 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 0.5434/1.576, allocations: 74.42 MB / 0.7399 GB, free: 190.9 MB / 0.5262 GB
Notification: Performance of preOpt comSubExp (simulation): time 0.02151/1.598, allocations: 8.51 MB / 0.7482 GB, free: 187.6 MB / 0.5262 GB
Notification: Performance of preOpt resolveLoops (simulation): time 0.00595/1.604, allocations: 4.779 MB / 0.7529 GB, free: 185 MB / 0.5262 GB
Notification: Performance of preOpt evalFunc (simulation): time 0.0285/1.633, allocations: 15.4 MB / 0.7679 GB, free: 173 MB / 0.5262 GB
Notification: Performance of preOpt encapsulateWhenConditions (simulation): time 7.86e-05/1.633, allocations: 76.08 kB / 0.768 GB, free: 172.9 MB / 0.5262 GB
Notification: Performance of pre-optimization done (n=321): time 8.355e-06/1.633, allocations: 0 / 0.768 GB, free: 172.9 MB / 0.5262 GB
Notification: Performance of matching and sorting (n=428): time 0.1814/1.814, allocations: 54.62 MB / 0.8213 GB, free: 118.4 MB / 0.5262 GB
Notification: Performance of inlineWhenForInitialization (initialization): time 0.0001101/1.814, allocations: 402.8 kB / 0.8217 GB, free: 118 MB / 0.5262 GB
Notification: Performance of selectInitializationVariablesDAE (initialization): time 0.009909/1.824, allocations: 7.563 MB / 0.8291 GB, free: 110.4 MB / 0.5262 GB
Notification: Performance of collectPreVariables (initialization): time 0.001228/1.825, allocations: 93.7 kB / 0.8292 GB, free: 110.3 MB / 0.5262 GB
Notification: Performance of collectInitialEqns (initialization): time 0.003109/1.829, allocations: 5.596 MB / 0.8346 GB, free: 104.7 MB / 0.5262 GB
Notification: Performance of collectInitialBindings (initialization): time 0.002171/1.831, allocations: 1.559 MB / 0.8362 GB, free: 103.2 MB / 0.5262 GB
Notification: Performance of simplifyInitialFunctions (initialization): time 0.002978/1.834, allocations: 2.082 MB / 0.8382 GB, free: 101.1 MB / 0.5262 GB
Notification: Performance of setup shared object (initialization): time 5.304e-05/1.834, allocations: 301.1 kB / 0.8385 GB, free: 100.8 MB / 0.5262 GB
Notification: Performance of preBalanceInitialSystem (initialization): time 0.006245/1.84, allocations: 5.221 MB / 0.8436 GB, free: 95.57 MB / 0.5262 GB
Notification: Performance of partitionIndependentBlocks (initialization): time 0.0086/1.849, allocations: 10.27 MB / 0.8536 GB, free: 82.88 MB / 0.5262 GB
Notification: Performance of analyzeInitialSystem (initialization): time 0.01711/1.866, allocations: 16.31 MB / 0.8695 GB, free: 64.16 MB / 0.5262 GB
Notification: Performance of solveInitialSystemEqSystem (initialization): time 0.0001489/1.866, allocations: 52 kB / 0.8696 GB, free: 64.11 MB / 0.5262 GB
Notification: Performance of matching and sorting (n=1335) (initialization): time 0.04087/1.907, allocations: 21.25 MB / 0.8903 GB, free: 42.84 MB / 0.5262 GB
Notification: Performance of prepare postOptimizeDAE: time 0.0001077/1.907, allocations: 80 kB / 0.8904 GB, free: 42.76 MB / 0.5262 GB
Notification: Performance of postOpt simplifyComplexFunction (initialization): time 0.000189/1.907, allocations: 171.9 kB / 0.8906 GB, free: 42.59 MB / 0.5262 GB
Notification: Performance of postOpt tearingSystem (initialization): time 0.01949/1.927, allocations: 6.653 MB / 0.8971 GB, free: 35.93 MB / 0.5262 GB
Notification: Performance of postOpt solveSimpleEquations (initialization): time 0.007227/1.934, allocations: 2.156 MB / 0.8992 GB, free: 33.77 MB / 0.5262 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (initialization): time 0.04257/1.977, allocations: 32.79 MB / 0.9312 GB, free: 0.832 MB / 0.5262 GB
Notification: Performance of postOpt simplifyAllExpressions (initialization): time 0.008561/1.985, allocations: 0.6279 MB / 0.9318 GB, free: 208 kB / 0.5262 GB
Notification: Performance of postOpt collapseArrayExpressions (initialization): time 0.2262/2.211, allocations: 0.5235 MB / 0.9323 GB, free: 212 MB / 0.5262 GB
Notification: Model statistics after passing the back-end for initialization:
 * Number of independent subsystems: 778
 * Number of states: 0 ()
 * Number of discrete variables: 73 (jointRRP.jointUSP.prismatic.positiveBranch,jointRRP.jointUSP.rod1Color[3],jointRRP.jointUSP.rod1Color[2],jointRRP.jointUSP.rod1Color[1],jointRRP.jointUSP.cylinderColor[3],jointRRP.jointUSP.cylinderColor[2],jointRRP.jointUSP.cylinderColor[1],jointRRP.jointUSP.sphereColor[3],jointRRP.jointUSP.sphereColor[2],jointRRP.jointUSP.sphereColor[1],jointRRP.rodColor[3],jointRRP.rodColor[2],jointRRP.rodColor[1],jointRRP.cylinderColor[3],jointRRP.cylinderColor[2],jointRRP.cylinderColor[1],cylPosition.color[3],cylPosition.color[2],cylPosition.color[1],mid.color[3],mid.color[2],mid.color[1],crank4.color[3],crank4.color[2],crank4.color[1],crank4.body.sphereColor[3],crank4.body.sphereColor[2],crank4.body.sphereColor[1],crank3.color[3],crank3.color[2],crank3.color[1],crank3.body.sphereColor[3],crank3.body.sphereColor[2],crank3.body.sphereColor[1],crank2.color[3],crank2.color[2],crank2.color[1],crank2.body.sphereColor[3],crank2.body.sphereColor[2],crank2.body.sphereColor[1],crank1.color[3],crank1.color[2],crank1.color[1],crank1.body.sphereColor[3],crank1.body.sphereColor[2],crank1.body.sphereColor[1],bearing.cylinderColor[3],bearing.cylinderColor[2],bearing.cylinderColor[1],connectingRod.color[3],connectingRod.color[2],connectingRod.color[1],connectingRod.body.sphereColor[3],connectingRod.body.sphereColor[2],connectingRod.body.sphereColor[1],piston.color[3],piston.color[2],piston.color[1],piston.body.sphereColor[3],piston.body.sphereColor[2],piston.body.sphereColor[1],world.gravityArrowColor[3],world.gravityArrowColor[2],world.gravityArrowColor[1],world.axisColor_x[3],world.axisColor_x[2],world.axisColor_x[1],world.groundColor[3],world.groundColor[2],world.groundColor[1],world.gravitySphereColor[3],world.gravitySphereColor[2],world.gravitySphereColor[1])
 * Number of discrete states: 0 ()
 * Number of clocked states: 0 ()
 * Top-level inputs: 0
Notification: Strong component statistics for initialization (1178):
 * Single equations (assignments): 1173
 * Array equations: 4
 * 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): 1 system
   {(3,129,100.0%)}
 * Non-linear torn systems (#iteration vars, #inner vars): 0 systems
Notification: Performance of prepare postOptimizeDAE: time 0.009663/2.221, allocations: 4.101 MB / 0.9363 GB, free: 211.9 MB / 0.5262 GB
Notification: Performance of postOpt lateInlineFunction (simulation): time 0.001817/2.223, allocations: 0.6978 MB / 0.937 GB, free: 211.9 MB / 0.5262 GB
Notification: Performance of postOpt wrapFunctionCalls (simulation): time 0.02933/2.252, allocations: 14.32 MB / 0.951 GB, free: 207.9 MB / 0.5262 GB
Notification: Performance of postOpt inlineArrayEqn (simulation): time 0.0001113/2.253, allocations: 47.03 kB / 0.9511 GB, free: 207.9 MB / 0.5262 GB
Notification: Performance of postOpt constantLinearSystem (simulation): time 4.096e-05/2.253, allocations: 23.59 kB / 0.9511 GB, free: 207.9 MB / 0.5262 GB
Notification: Performance of postOpt simplifysemiLinear (simulation): time 9.477e-05/2.253, allocations: 23.23 kB / 0.9511 GB, free: 207.9 MB / 0.5262 GB
Notification: Performance of postOpt removeSimpleEquations (simulation): time 0.05634/2.309, allocations: 28.24 MB / 0.9787 GB, free: 194.5 MB / 0.5262 GB
Notification: Performance of postOpt simplifyComplexFunction (simulation): time 5.265e-05/2.309, allocations: 11.03 kB / 0.9787 GB, free: 194.5 MB / 0.5262 GB
Notification: Performance of postOpt solveSimpleEquations (simulation): time 0.002793/2.312, allocations: 0.5928 MB / 0.9793 GB, free: 193.9 MB / 0.5262 GB
Notification: Performance of postOpt tearingSystem (simulation): time 0.01766/2.33, allocations: 6.316 MB / 0.9854 GB, free: 187.6 MB / 0.5262 GB
Notification: Performance of postOpt inputDerivativesUsed (simulation): time 0.001054/2.331, allocations: 83.92 kB / 0.9855 GB, free: 187.5 MB / 0.5262 GB
Notification: Performance of postOpt calculateStrongComponentJacobians (simulation): time 0.03476/2.365, allocations: 29.73 MB / 1.015 GB, free: 157.9 MB / 0.5262 GB
Notification: Performance of postOpt calculateStateSetsJacobians (simulation): time 6.452e-06/2.365, allocations: 11.94 kB / 1.015 GB, free: 157.9 MB / 0.5262 GB
Notification: Performance of postOpt symbolicJacobian (simulation): time 0.6481/3.014, allocations: 185.2 MB / 1.195 GB, free: 174.3 MB / 0.5262 GB
Notification: Performance of postOpt removeConstants (simulation): time 0.005314/3.019, allocations: 1.561 MB / 1.197 GB, free: 173.8 MB / 0.5262 GB
Notification: Performance of postOpt simplifyTimeIndepFuncCalls (simulation): time 0.002038/3.021, allocations: 86.17 kB / 1.197 GB, free: 173.8 MB / 0.5262 GB
Notification: Performance of postOpt simplifyAllExpressions (simulation): time 0.004952/3.026, allocations: 327 kB / 1.197 GB, free: 173.7 MB / 0.5262 GB
Notification: Performance of postOpt findZeroCrossings (simulation): time 0.001271/3.027, allocations: 300.9 kB / 1.198 GB, free: 173.7 MB / 0.5262 GB
Notification: Performance of postOpt collapseArrayExpressions (simulation): time 0.0004295/3.028, allocations: 118 kB / 1.198 GB, free: 173.6 MB / 0.5262 GB
Notification: Performance of sorting global known variables: time 0.008068/3.036, allocations: 4.827 MB / 1.202 GB, free: 172.1 MB / 0.5262 GB
Notification: Performance of sort global known variables: time 7.62e-07/3.036, allocations: 2.844 kB / 1.202 GB, free: 172.1 MB / 0.5262 GB
Notification: Performance of remove unused functions: time 0.01733/3.053, allocations: 3.432 MB / 1.206 GB, free: 168.7 MB / 0.5262 GB
Notification: Model statistics after passing the back-end for simulation:
 * Number of independent subsystems: 34
 * Number of states: 2 (inertia.phi,inertia.w)
 * 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 (296):
 * Single equations (assignments): 292
 * Array equations: 3
 * 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): 1 system
   {(3,116,77.8%)}
 * Non-linear torn systems (#iteration vars, #inner vars): 0 systems
Notification: Performance of Backend phase and start with SimCode phase: time 0.002019/3.055, allocations: 278.6 kB / 1.206 GB, free: 168.5 MB / 0.5262 GB
Notification: Performance of simCode: created initialization part: time 0.01967/3.075, allocations: 12.71 MB / 1.218 GB, free: 157.3 MB / 0.5262 GB
Notification: Performance of simCode: created event and clocks part: time 1.544e-05/3.075, allocations: 4 kB / 1.218 GB, free: 157.3 MB / 0.5262 GB
Notification: Performance of simCode: created simulation system equations: time 0.008473/3.083, allocations: 5.342 MB / 1.224 GB, free: 152.6 MB / 0.5262 GB
Notification: Performance of simCode: created of all other equations (e.g. parameter, nominal, assert, etc): time 0.01/3.093, allocations: 1.017 MB / 1.225 GB, free: 151.7 MB / 0.5262 GB
Notification: Performance of simCode: created linear, non-linear and system jacobian parts: time 0.05812/3.152, allocations: 30.64 MB / 1.255 GB, free: 124.2 MB / 0.5262 GB
Notification: Performance of simCode: some other stuff during SimCode phase: time 0.01375/3.165, allocations: 6.559 MB / 1.261 GB, free: 117.7 MB / 0.5262 GB
Notification: Performance of simCode: alias equations: time 0.01013/3.176, allocations: 3.044 MB / 1.264 GB, free: 114.7 MB / 0.5262 GB
Notification: Performance of simCode: all other stuff during SimCode phase: time 0.002722/3.178, allocations: 455.4 kB / 1.264 GB, free: 114.2 MB / 0.5262 GB
Notification: Performance of SimCode: time 1.713e-06/3.178, allocations: 0 / 1.264 GB, free: 114.2 MB / 0.5262 GB
Notification: Performance of Templates: time 0.5628/3.741, allocations: 160.7 MB / 1.421 GB, free: 146.6 MB / 0.5262 GB
make -j1 -f Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.makefile
(rm -f Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.pipe ; mkfifo Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.pipe ; head -c 1048576 < Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.pipe >> ../files/Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.sim & ./Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic  -abortSlowSimulation -alarm=480  -emit_protected -lv LOG_STATS > Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.pipe 2>&1)
diffSimulationResults("Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic_res.mat","/var/lib/jenkins/ws/OpenModelicaLibraryTestingWork@2/Reference-modelica.org/ReferenceResults/MAP-LIB_ReferenceResults/v4.0.0/Modelica/Mechanics/MultiBody/Examples/Loops/Engine1b_analytic/Engine1b_analytic.csv","../files/Modelica_4.0.0_Modelica.Mechanics.MultiBody.Examples.Loops.Engine1b_analytic.diff",relTol=0.003,relTolDiffMinMax=0.003,rangeDelta=0.001)
Reference file matches