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| Code Block |
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| language | cpp |
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| title | FlippinFelinesOptimizerSystem.h |
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// Set (nondimensional) parameter limits/bounds for the actuators.
SimTK::Vector lowerLimits(getNumParameters(), -1.0);
SimTK::Vector upperLimits(getNumParameters(), 1.0);
setParameterLimits(lowerLimits, upperLimits); |
C.4: Initial parameters
We wanted to make it really easy for the user to specify the initial parameters for the optimization. Since they parameters end up as Y-coordinates of splines, we thought this would be the easiest way for a user to specify the initial parameters. However, we need the initial parameters as a Vector. So, we wrote a method to convert the Y-coordinates from a FunctionSet of SimmSpline's into a Vector.
| Code Block |
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| language | cpp |
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| title | FlippinFelinesOptimizerSystem.h |
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| collapse | true |
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|
SimTK::Vector initialParameters()
{
SimTK::Vector initParams(getNumParameters(), 0.0);
if (_tool.get_initial_parameters_filename() != "")
{ // A file is specified.
// Deserialize the initial parameters XML file.
OpenSim::FunctionSet initFcns(_tool.get_initial_parameters_filename());
// Write a copy of the FunctionSet to the results directory.
initFcns.print(_name + "/" + _name + "_initial_parameters.xml");
OpenSim::Array<std::string> initNames;
initFcns.getNames(initNames);
// This loop is set up so that the initFcns do not need to be in the same
// order as the optimization parameters. Also, the number of initFcns
// specified by the initial parameters file can be greater than the
// number of actuators in the model (assuming that the initial parameters
// file AT LEAST contains the model's actuators).
using OpenSim::SimmSpline;
for (int iAct = 0; iAct < _numActuators; iAct++)
{
// Get index of the initFcn corresponding to the actuator.
int iFcn = initFcns.getIndex(_cat.getActuators().get(iAct).getName());
// Get access to the spline's methods.
SimmSpline * fcn =
dynamic_cast<SimmSpline *>(&initFcns.get(iFcn));
for (int iPts = 0; iPts < _numOptimSplinePoints; iPts++)
{
// Find the right index in the optimization parameters.
int paramIndex = iAct * _numOptimSplinePoints + iPts;
// Transfer y value from input to initial parameters.
initParams[paramIndex] = fcn->getY(iPts);
}
}
}
return initParams;
} |
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We now return to objectiveFunc(), right after the code where we've finished assembling fassembled f. We update the log with new objective function value, and might print an updated model file and updated control functions.
| Code Block |
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| language | cpp |
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| title | FlippinFelinesOptimizerSystem.h |
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| collapse | true |
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_lastCallWasBestYet = _thisCallIsBestYet;
_thisCallIsBestYet = f <= _objectiveFcnValueBestYet;
if (_thisCallIsBestYet) _objectiveFcnValueBestYet = f;
if (_objectiveCalls % _outputPeriod == 0)
_optLog << " objfcn " << f << " objfcn_best_yet " << _objectiveFcnValueBestYet << std::endl;
// If this is the best yet (i.e., smallest objective function value),
// save a copy of the splines.
if (_thisCallIsBestYet)
{
for (unsigned int iFcn = 0; iFcn < _splinesBestYet.size(); iFcn++)
_splinesBestYet[iFcn] = *_splines[iFcn];
}
// If this is worse, print out the best-yet splines and current model
// (NOTE: current model is NOT "best yet", but the idea is that it will
// be close). Also print out nondimensionalized splines so that they can
// be used directly as input for a subsequent optimization.
if (_lastCallWasBestYet && !_thisCallIsBestYet)
{
printBestYetPrescribedControllerFunctionSet(
_name + "_best_yet_parameters.xml");
printBestYetPrescribedControllerFunctionSet(
_name + "_best_yet_parameters_nomdim.xml", true);
printModel(_name + "_best_yet.osim");
}
// Print out to the terminal/console every so often.
if (_objectiveCalls % _outputPeriod == 0)
std::cout << "Objective call # " << _objectiveCalls << std::endl;
return 0; |
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