documenting units and making gravity a named constant, refs eclipse-s…

…umo#2, eclipse-sumo#12

src/mesosim/MEVehicle.h

@@ -70,7 +70,7 @@ class MEVehicle : public MSBaseVehicle {
     double getAngle() const;
 
 
-    /** @brief Returns the slope of the road at vehicle's position
+    /** @brief Returns the slope of the road at vehicle's position in degrees
      * @return The slope
      */
     double getSlope() const;

src/microsim/MSBaseVehicle.cpp

@@ -491,12 +491,6 @@ MSBaseVehicle::getAcceleration() const {
 }
 
 
-double
-MSBaseVehicle::getSlope() const {
-    return 0;
-}
-
-
 void
 MSBaseVehicle::onDepart() {
     myDeparture = MSNet::getInstance()->getCurrentTimeStep();

src/microsim/MSBaseVehicle.h

@@ -270,13 +270,6 @@ class MSBaseVehicle : public SUMOVehicle {
      */
     virtual double getAcceleration() const;
 
-    /** @brief Returns the slope of the road at vehicle's position
-     *
-     * This default implementation returns always 0.
-     * @return The slope
-     */
-    virtual double getSlope() const;
-
     /** @brief Called when the vehicle is inserted into the network
      *
      * Sets optional information about departure time, informs the vehicle

src/microsim/MSVehicle.h

@@ -540,7 +540,7 @@ class MSVehicle : public MSBaseVehicle {
     /// @name Other getter methods
     //@{
 
-    /** @brief Returns the slope of the road at vehicle's position
+    /** @brief Returns the slope of the road at vehicle's position in degrees
      * @return The slope
      */
     double getSlope() const;

src/microsim/cfmodels/MSCFModel_KraussPS.cpp

@@ -42,8 +42,7 @@ MSCFModel_KraussPS::~MSCFModel_KraussPS() {}
 
 double
 MSCFModel_KraussPS::maxNextSpeed(double speed, const MSVehicle* const veh) const {
-    const double gravity = 9.80665;
-    const double aMax = MAX2(0., getMaxAccel() - gravity * sin(DEG2RAD(veh->getSlope())));
+    const double aMax = MAX2(0., getMaxAccel() - GRAVITY * sin(DEG2RAD(veh->getSlope())));
     // assuming drag force is proportional to the square of speed
     const double vMax = MAX2(
                             sqrt(aMax / getMaxAccel()) * myType->getMaxSpeed(),

src/microsim/cfmodels/MSCFModel_Rail.cpp

@@ -27,8 +27,6 @@
 #include <microsim/lcmodels/MSAbstractLaneChangeModel.h>
 #include "MSCFModel_Rail.h"
 
-#define G  9.80665
-
 MSCFModel_Rail::MSCFModel_Rail(const MSVehicleType* vtype) :
     MSCFModel(vtype) {
     const std::string trainType = vtype->getParameter().getCFParamString(SUMO_ATTR_TRAIN_TYPE, "NGT400");
@@ -117,7 +115,7 @@ double MSCFModel_Rail::maxNextSpeed(double speed, const MSVehicle* const veh) co
     double res = getInterpolatedValueFromLookUpMap(speed, &(myTrainParams.resistance)); // kN
 
     double slope = veh->getSlope();
-    double gr = myTrainParams.weight * G * sin(DEG2RAD(slope)); //kN
+    double gr = myTrainParams.weight * GRAVITY * sin(DEG2RAD(slope)); //kN
 
     double totalRes = res + gr; //kN
 
@@ -143,7 +141,7 @@ double MSCFModel_Rail::maxNextSpeed(double speed, const MSVehicle* const veh) co
 double MSCFModel_Rail::minNextSpeed(double speed, const MSVehicle* const veh) const {
 
     const double slope = veh->getSlope();
-    const double gr = myTrainParams.weight * G * sin(DEG2RAD(slope)); //kN
+    const double gr = myTrainParams.weight * GRAVITY * sin(DEG2RAD(slope)); //kN
     const double res = getInterpolatedValueFromLookUpMap(speed, &(myTrainParams.resistance)); // kN
     const double totalRes = res + gr; //kN
     const double a = myTrainParams.decl + totalRes / myTrainParams.rotWeight;
@@ -205,7 +203,7 @@ double MSCFModel_Rail::getInterpolatedValueFromLookUpMap(double speed, const Loo
 double MSCFModel_Rail::getSpeedAfterMaxDecel(double /* speed */) const {
 
 //    //TODO: slope not known here
-//    double gr = 0; //trainParams.weight * 9.81 * edge.grade
+//    double gr = 0; //trainParams.weight * GRAVITY * edge.grade
 //
 //    double a = 0;//trainParams.decl - gr/trainParams.rotWeight;
 //

src/utils/emissions/HelpersEnergy.cpp

@@ -68,7 +68,7 @@ HelpersEnergy::compute(const SUMOEmissionClass /* c */, const PollutantsInterfac
     const double mass = param->find(SUMO_ATTR_VEHICLEMASS)->second;
 
     // calculate potential energy difference
-    double energyDiff = mass * 9.81 * sin(DEG2RAD(slope)) * SPEED2DIST(v);
+    double energyDiff = mass * GRAVITY * sin(DEG2RAD(slope)) * SPEED2DIST(v);
 
     // kinetic energy difference of vehicle
     energyDiff += 0.5 * mass * (v * v - lastV * lastV);
@@ -88,7 +88,7 @@ HelpersEnergy::compute(const SUMOEmissionClass /* c */, const PollutantsInterfac
     // EnergyLoss,Tire = c_R [-] * F_N [N] * s [m]
     //                    ... with c_R = ~0.012    (car tire on asphalt)
     //                    ... with F_N [N] = myMass [kg] * g [m/s^2]
-    energyDiff += param->find(SUMO_ATTR_ROLLDRAGCOEFFICIENT)->second * 9.81 * mass * SPEED2DIST(v);
+    energyDiff += param->find(SUMO_ATTR_ROLLDRAGCOEFFICIENT)->second * GRAVITY * mass * SPEED2DIST(v);
 
     // Energy loss through friction by radial force [Ws]
     // If angle of vehicle was changed
@@ -167,16 +167,16 @@ HelpersEnergy::acceleration(const SUMOEmissionClass /* c */, const PollutantsInt
     }
 
     // calculate power drop due to a potential energy difference
-    Prest -= mass * 9.81 * sin(DEG2RAD(slope)) * (v);
-    const1 = mass * 9.81 * sin(DEG2RAD(slope)) * (TS);
+    Prest -= mass * GRAVITY * sin(DEG2RAD(slope)) * (v);
+    const1 = mass * GRAVITY * sin(DEG2RAD(slope)) * (TS);
 
     // Power loss through Roll resistance [W]
     //                    ... (fabs(veh.getSpeed())>=0.01) = 0, if vehicle isn't moving
     // EnergyLoss,Tire = c_R [-] * F_N [N] * s [m]
     //                    ... with c_R = ~0.012    (car tire on asphalt)
     //                    ... with F_N [N] = myMass [kg] * g [m/s^2]
-    Prest -= param->find(SUMO_ATTR_ROLLDRAGCOEFFICIENT)->second * 9.81 * mass * v;
-    const1 += param->find(SUMO_ATTR_ROLLDRAGCOEFFICIENT)->second * 9.81 * mass * (TS);
+    Prest -= param->find(SUMO_ATTR_ROLLDRAGCOEFFICIENT)->second * GRAVITY * mass * v;
+    const1 += param->find(SUMO_ATTR_ROLLDRAGCOEFFICIENT)->second * GRAVITY * mass * (TS);
 
     //Constant loads are omitted. We assume P as the max limit for the main traction drive. Constant loads are often covered by an auxiliary drive
     //Power loss through constant loads (e.g. A/C) [W]

src/utils/emissions/HelpersHBEFA.h

@@ -81,7 +81,7 @@ class HelpersHBEFA : public PollutantsInterface::Helper {
             return 0.;
         }
         const double* f = myFunctionParameter[index] + 6 * e;
-        const double alpha = asin(a / 9.81) * 180. / M_PI;
+        const double alpha = RAD2DEG(asin(a / GRAVITY));
         return (double) MAX2((f[0] + f[1] * alpha * kmh + f[2] * alpha * alpha * kmh + f[3] * kmh + f[4] * kmh * kmh + f[5] * kmh * kmh * kmh) / scale, 0.);
     }
 

src/utils/geom/GeomHelper.h

@@ -34,6 +34,7 @@
 
 #define DEG2RAD(x) static_cast<double>((x) * M_PI / 180.)
 #define RAD2DEG(x) static_cast<double>((x) * 180. / M_PI)
+#define GRAVITY 9.80665
 
 
 // ===========================================================================

src/utils/vehicle/SUMOTrafficObject.h

@@ -111,7 +111,7 @@ class SUMOTrafficObject : public Named {
      */
     virtual const MSEdge* getEdge() const = 0;
 
-    /** @brief Returns the slope of the road at object's position
+    /** @brief Returns the slope of the road at object's position in degrees
      * @return The slope
      */
     virtual double getSlope() const = 0;