// simulate the given FMU using the forward euler method.
// time events are processed by reducing step size to exactly hit tNext.
// state events are checked and fired only at the end of an Euler step.
// the simulator may therefore miss state events and fires state events typically too late.
static int simulate(FMU* fmu, double tEnd, double h, fmi2Boolean loggingOn, char separator,
int nCategories, const fmi2String categories[]) {
int i;
double dt, tPre;
fmi2Boolean timeEvent, stateEvent, stepEvent, terminateSimulation;
double time;
int nx; // number of state variables
int nz; // number of state event indicators
double *x = NULL; // continuous states
double *xdot = NULL; // the corresponding derivatives in same order
double *z = NULL; // state event indicators
double *prez = NULL; // previous values of state event indicators
fmi2EventInfo eventInfo; // updated by calls to initialize and eventUpdate
ModelDescription* md; // handle to the parsed XML file
const char* guid; // global unique id of the fmu
fmi2CallbackFunctions callbacks = {fmuLogger, calloc, free, NULL, fmu}; // called by the model during simulation
fmi2Component c; // instance of the fmu
fmi2Status fmi2Flag; // return code of the fmu functions
fmi2Real tStart = 0; // start time
fmi2Boolean toleranceDefined = fmi2False; // true if model description define tolerance
fmi2Real tolerance = 0; // used in setting up the experiment
fmi2Boolean visible = fmi2False; // no simulator user interface
const char *instanceName; // instance name
char *fmuResourceLocation = getTempResourcesLocation(); // path to the fmu resources as URL, "file://C:\QTronic\sales"
int nSteps = 0;
int nTimeEvents = 0;
int nStepEvents = 0;
int nStateEvents = 0;
FILE* file;
ValueStatus vs;
// instantiate the fmu
md = fmu->modelDescription;
guid = getAttributeValue((Element *)md, att_guid);
instanceName = getAttributeValue((Element *)getModelExchange(md), att_modelIdentifier);
c = fmu->instantiate(instanceName, fmi2ModelExchange, guid, fmuResourceLocation,
&callbacks, visible, loggingOn);
free(fmuResourceLocation);
if (!c) return error("could not instantiate model");
if (nCategories > 0) {
fmi2Flag = fmu->setDebugLogging(c, fmi2True, nCategories, categories);
if (fmi2Flag > fmi2Warning) {
return error("could not initialize model; failed FMI set debug logging");
}
}
// allocate memory
nx = getDerivativesSize(getModelStructure(md)); // number of continuous states is number of derivatives
// declared in model structure
nz = getAttributeInt((Element *)md, att_numberOfEventIndicators, &vs); // number of event indicators
x = (double *) calloc(nx, sizeof(double));
xdot = (double *) calloc(nx, sizeof(double));
if (nz>0) {
z = (double *) calloc(nz, sizeof(double));
prez = (double *) calloc(nz, sizeof(double));
}
if ((!x || !xdot) || (nz>0 && (!z || !prez))) return error("out of memory");
// open result file
if (!(file = fopen(RESULT_FILE, "w"))) {
printf("could not write %s because:\n", RESULT_FILE);
printf(" %s\n", strerror(errno));
free (x);
free(xdot);
free(z);
free(prez);
return 0; // failure
}
// setup the experiment, set the start time
time = tStart;
fmi2Flag = fmu->setupExperiment(c, toleranceDefined, tolerance, tStart, fmi2True, tEnd);
if (fmi2Flag > fmi2Warning) {
return error("could not initialize model; failed FMI setup experiment");
}
// initialize
fmi2Flag = fmu->enterInitializationMode(c);
if (fmi2Flag > fmi2Warning) {
return error("could not initialize model; failed FMI enter initialization mode");
}
fmi2Flag = fmu->exitInitializationMode(c);
if (fmi2Flag > fmi2Warning) {
return error("could not initialize model; failed FMI exit initialization mode");
}
// event iteration
eventInfo.newDiscreteStatesNeeded = fmi2True;
eventInfo.terminateSimulation = fmi2False;
while (eventInfo.newDiscreteStatesNeeded && !eventInfo.terminateSimulation) {
// update discrete states
fmi2Flag = fmu->newDiscreteStates(c, &eventInfo);
if (fmi2Flag > fmi2Warning) return error("could not set a new discrete state");
}
if (eventInfo.terminateSimulation) {
printf("model requested termination at t=%.16g\n", time);
} else {
// enter Continuous-Time Mode
fmu->enterContinuousTimeMode(c);
// output solution for time tStart
outputRow(fmu, c, tStart, file, separator, fmi2True); // output column names
outputRow(fmu, c, tStart, file, separator, fmi2False); // output values
// enter the simulation loop
while (time < tEnd) {
// get current state and derivatives
fmi2Flag = fmu->getContinuousStates(c, x, nx);
if (fmi2Flag > fmi2Warning) return error("could not retrieve states");
fmi2Flag = fmu->getDerivatives(c, xdot, nx);
if (fmi2Flag > fmi2Warning) return error("could not retrieve derivatives");
// advance time
tPre = time;
time = min(time+h, tEnd);
timeEvent = eventInfo.nextEventTimeDefined && eventInfo.nextEventTime <= time;
if (timeEvent) time = eventInfo.nextEventTime;
dt = time - tPre;
fmi2Flag = fmu->setTime(c, time);
if (fmi2Flag > fmi2Warning) error("could not set time");
// perform one step
for (i = 0; i < nx; i++) x[i] += dt * xdot[i]; // forward Euler method
fmi2Flag = fmu->setContinuousStates(c, x, nx);
if (fmi2Flag > fmi2Warning) return error("could not set states");
if (loggingOn) printf("Step %d to t=%.16g\n", nSteps, time);
// check for state event
for (i = 0; i < nz; i++) prez[i] = z[i];
fmi2Flag = fmu->getEventIndicators(c, z, nz);
if (fmi2Flag > fmi2Warning) return error("could not retrieve event indicators");
stateEvent = FALSE;
for (i=0; i<nz; i++)
stateEvent = stateEvent || (prez[i] * z[i] < 0);
// check for step event, e.g. dynamic state selection
fmi2Flag = fmu->completedIntegratorStep(c, fmi2True, &stepEvent, &terminateSimulation);
if (fmi2Flag > fmi2Warning) return error("could not complete intgrator step");
if (terminateSimulation) {
printf("model requested termination at t=%.16g\n", time);
break; // success
}
// handle events
if (timeEvent || stateEvent || stepEvent) {
fmu->enterEventMode(c);
if (timeEvent) {
nTimeEvents++;
if (loggingOn) printf("time event at t=%.16g\n", time);
}
if (stateEvent) {
nStateEvents++;
if (loggingOn) for (i=0; i<nz; i++)
printf("state event %s z[%d] at t=%.16g\n",
(prez[i]>0 && z[i]<0) ? "-\\-" : "-/-", i, time);
}
if (stepEvent) {
nStepEvents++;
if (loggingOn) printf("step event at t=%.16g\n", time);
}
// event iteration in one step, ignoring intermediate results
eventInfo.newDiscreteStatesNeeded = fmi2True;
eventInfo.terminateSimulation = fmi2False;
while (eventInfo.newDiscreteStatesNeeded && !eventInfo.terminateSimulation) {
// update discrete states
fmi2Flag = fmu->newDiscreteStates(c, &eventInfo);
if (fmi2Flag > fmi2Warning) return error("could not set a new discrete state");
}
if (eventInfo.terminateSimulation) {
printf("model requested termination at t=%.16g\n", time);
break; // success
}
// enter Continuous-Time Mode
fmu->enterContinuousTimeMode(c);
// check for change of value of states
if (eventInfo.valuesOfContinuousStatesChanged && loggingOn) {
printf("continuous state values changed at t=%.16g\n", time);
}
if (eventInfo.nominalsOfContinuousStatesChanged && loggingOn){
printf("nominals of continuous state changed at t=%.16g\n", time);
}
} // if event
outputRow(fmu, c, time, file, separator, fmi2False); // output values for this step
nSteps++;
} // while
}
// cleanup
fmu->terminate(c);
fmu->freeInstance(c);
fclose(file);
if (x != NULL) free(x);
if (xdot != NULL) free(xdot);
if (z != NULL) free(z);
if (prez != NULL) free(prez);
// print simulation summary
printf("Simulation from %g to %g terminated successful\n", tStart, tEnd);
printf(" steps ............ %d\n", nSteps);
printf(" fixed step size .. %g\n", h);
printf(" time events ...... %d\n", nTimeEvents);
printf(" state events ..... %d\n", nStateEvents);
printf(" step events ...... %d\n", nStepEvents);
return 1; // success
}
// simulate the given FMU using the forward euler method.
// time events are processed by reducing step size to exactly hit tNext.
// state events are checked and fired only at the end of an Euler step.
// the simulator may therefore miss state events and fires state events typically too late.
static int simulate(FMU* fmu, double tEnd, double h, fmiBoolean loggingOn, char separator) {
int i, n;
double dt, tPre;
fmiBoolean timeEvent, stateEvent, stepEvent;
double time;
int nx; // number of state variables
int nz; // number of state event indicators
double *x; // continuous states
double *xdot; // the crresponding derivatives in same order
double *z = NULL; // state event indicators
double *prez = NULL; // previous values of state event indicators
fmiEventInfo eventInfo; // updated by calls to initialize and eventUpdate
ModelDescription* md; // handle to the parsed XML file
const char* guid; // global unique id of the fmu
fmiCallbackFunctions callbacks; // called by the model during simulation
fmiComponent c; // instance of the fmu
fmiStatus fmiFlag; // return code of the fmu functions
fmiReal t0 = 0; // start time
fmiBoolean toleranceControlled = fmiFalse;
int nSteps = 0;
int nTimeEvents = 0;
int nStepEvents = 0;
int nStateEvents = 0;
FILE* file;
// instantiate the fmu
md = fmu->modelDescription;
guid = getString(md, att_guid);
callbacks.logger = fmuLogger;
callbacks.allocateMemory = calloc;
callbacks.freeMemory = free;
c = fmu->instantiateModel(getModelIdentifier(md), guid, callbacks, loggingOn);
if (!c) return error("could not instantiate model");
// allocate memory
nx = getNumberOfStates(md);
nz = getNumberOfEventIndicators(md);
x = (double *) calloc(nx, sizeof(double));
xdot = (double *) calloc(nx, sizeof(double));
if (nz>0) {
z = (double *) calloc(nz, sizeof(double));
prez = (double *) calloc(nz, sizeof(double));
}
if (!x || !xdot || nz>0 && (!z || !prez)) return error("out of memory");
// open result file
if (!(file=fopen(RESULT_FILE, "w"))) {
printf("could not write %s because:\n", RESULT_FILE);
printf(" %s\n", strerror(errno));
return 0; // failure
}
// set the start time and initialize
time = t0;
fmiFlag = fmu->setTime(c, t0);
if (fmiFlag > fmiWarning) return error("could not set time");
fmiFlag = fmu->initialize(c, toleranceControlled, t0, &eventInfo);
if (fmiFlag > fmiWarning) error("could not initialize model");
if (eventInfo.terminateSimulation) {
printf("model requested termination at init");
tEnd = time;
}
// output solution for time t0
outputRow(fmu, c, t0, file, separator, TRUE); // output column names
outputRow(fmu, c, t0, file, separator, FALSE); // output values
// enter the simulation loop
while (time < tEnd) {
// get current state and derivatives
fmiFlag = fmu->getContinuousStates(c, x, nx);
if (fmiFlag > fmiWarning) return error("could not retrieve states");
fmiFlag = fmu->getDerivatives(c, xdot, nx);
if (fmiFlag > fmiWarning) return error("could not retrieve derivatives");
// advance time
tPre = time;
time = min(time+h, tEnd);
timeEvent = eventInfo.upcomingTimeEvent && eventInfo.nextEventTime < time;
if (timeEvent) time = eventInfo.nextEventTime;
dt = time - tPre;
fmiFlag = fmu->setTime(c, time);
if (fmiFlag > fmiWarning) error("could not set time");
// perform one step
for (i=0; i<nx; i++) x[i] += dt*xdot[i]; // forward Euler method
fmiFlag = fmu->setContinuousStates(c, x, nx);
if (fmiFlag > fmiWarning) return error("could not set states");
if (loggingOn) printf("Step %d to t=%.16g\n", nSteps, time);
// Check for step event, e.g. dynamic state selection
fmiFlag = fmu->completedIntegratorStep(c, &stepEvent);
if (fmiFlag > fmiWarning) return error("could not complete intgrator step");
// Check for state event
for (i=0; i<nz; i++) prez[i] = z[i];
fmiFlag = fmu->getEventIndicators(c, z, nz);
if (fmiFlag > fmiWarning) return error("could not retrieve event indicators");
stateEvent = FALSE;
for (i=0; i<nz; i++)
stateEvent = stateEvent || (prez[i] * z[i] < 0);
// handle events
if (timeEvent || stateEvent || stepEvent) {
if (timeEvent) {
nTimeEvents++;
if (loggingOn) printf("time event at t=%.16g\n", time);
}
if (stateEvent) {
nStateEvents++;
if (loggingOn) for (i=0; i<nz; i++)
printf("state event %s z[%d] at t=%.16g\n",
(prez[i]>0 && z[i]<0) ? "-\\-" : "-/-", i, time);
}
if (stepEvent) {
nStepEvents++;
if (loggingOn) printf("step event at t=%.16g\n", time);
}
// event iteration in one step, ignoring intermediate results
fmiFlag = fmu->eventUpdate(c, fmiFalse, &eventInfo);
if (fmiFlag > fmiWarning) return error("could not perform event update");
// terminate simulation, if requested by the model
if (eventInfo.terminateSimulation) {
printf("model requested termination at t=%.16g\n", time);
break; // success
}
// check for change of value of states
if (eventInfo.stateValuesChanged && loggingOn) {
printf("state values changed at t=%.16g\n", time);
}
// check for selection of new state variables
if (eventInfo.stateValueReferencesChanged && loggingOn) {
printf("new state variables selected at t=%.16g\n", time);
}
} // if event
outputRow(fmu, c, time, file, separator, FALSE); // output values for this step
nSteps++;
} // while
// cleanup
fclose(file);
if (x!=NULL) free(x);
if (xdot!= NULL) free(xdot);
if (z!= NULL) free(z);
if (prez!= NULL) free(prez);
// print simulation summary
printf("Simulation from %g to %g terminated successful\n", t0, tEnd);
printf(" steps ............ %d\n", nSteps);
printf(" fixed step size .. %g\n", h);
printf(" time events ...... %d\n", nTimeEvents);
printf(" state events ..... %d\n", nStateEvents);
printf(" step events ...... %d\n", nStepEvents);
return 1; // success
}