MSCFModel_Krauss.cpp

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// Krauss car-following model, with acceleration decrease and faster start
/****************************************************************************/
// SUMO, Simulation of Urban MObility; see http://sumo.dlr.de/
// Copyright (C) 2001-2017 DLR (http://www.dlr.de/) and contributors
/****************************************************************************/
//
//   This file is part of SUMO.
//   SUMO is free software: you can redistribute it and/or modify
//   it under the terms of the GNU General Public License as published by
//   the Free Software Foundation, either version 3 of the License, or
//   (at your option) any later version.
//
/****************************************************************************/


// ===========================================================================
// included modules
// ===========================================================================
#ifdef _MSC_VER
#include <windows_config.h>
#else
#include <config.h>
#endif

#include <microsim/MSVehicle.h>
#include <microsim/MSLane.h>
#include <microsim/MSGlobals.h>
#include "MSCFModel_Krauss.h"
#include <microsim/lcmodels/MSAbstractLaneChangeModel.h>
#include <utils/common/RandHelper.h>


// ===========================================================================
// method definitions
// ===========================================================================
MSCFModel_Krauss::MSCFModel_Krauss(const MSVehicleType* vtype, double accel, double decel,
                                   double emergencyDecel, double apparentDecel,
                                   double dawdle, double headwayTime) :
    MSCFModel_KraussOrig1(vtype, accel, decel, emergencyDecel, apparentDecel, dawdle, headwayTime) {
}


MSCFModel_Krauss::~MSCFModel_Krauss() {}


double
MSCFModel_Krauss::stopSpeed(const MSVehicle* const veh, const double speed, double gap) const {
    // NOTE: This allows return of smaller values than minNextSpeed().
    // Only relevant for the ballistic update: We give the argument headway=TS, to assure that
    // the stopping position is approached with a uniform deceleration also for tau!=TS.
    return MIN2(maximumSafeStopSpeed(gap, speed, false, TS), maxNextSpeed(speed, veh));
}


double
MSCFModel_Krauss::followSpeed(const MSVehicle* const veh, double speed, double gap, double predSpeed, double predMaxDecel) const {
    const double vsafe = maximumSafeFollowSpeed(gap, speed, predSpeed, predMaxDecel);
    const double vmin = minNextSpeed(speed);
    const double vmax = maxNextSpeed(speed, veh);
    if (MSGlobals::gSemiImplicitEulerUpdate) {
        return MIN2(vsafe, vmax);
    } else {
        // ballistic
        // XXX: the euler variant can break as strong as it wishes immediately! The ballistic cannot, refs. #2575.
        return MAX2(MIN2(vsafe, vmax), vmin);
    }
}


double
MSCFModel_Krauss::dawdle(double speed) const {
    if (!MSGlobals::gSemiImplicitEulerUpdate) {
        // in case of the ballistic update, negative speeds indicate
        // a desired stop before the completion of the next timestep.
        // We do not allow dawdling to overwrite this indication
        if (speed < 0) {
            return speed;
        }
    }
    // generate random number out of [0,1)
    const double random = RandHelper::rand();
    // Dawdle.
    if (speed < myAccel) {
        // we should not prevent vehicles from driving just due to dawdling
        //  if someone is starting, he should definitely start
        // (but what about slow-to-start?)!!!
        speed -= ACCEL2SPEED(myDawdle * speed * random);
    } else {
        speed -= ACCEL2SPEED(myDawdle * myAccel * random);
    }
    return MAX2(0., speed);
}


MSCFModel*
MSCFModel_Krauss::duplicate(const MSVehicleType* vtype) const {
    return new MSCFModel_Krauss(vtype, myAccel, myDecel, myEmergencyDecel, myApparentDecel, myDawdle, myHeadwayTime);
}


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