change continuous events to exponential; no longer letting them chang…

…e timestep

grss/version.txt

@@ -1 +1 @@
-4.2.3
+4.3.0

include/simulation.h

@@ -242,7 +242,8 @@ class Event {
     real multiplier = 1.0L;
 
     // for continuous ejecta events
-    real dt = 1.0L;
+    std::vector<real> expAccel0 = {0.0L, 0.0L, 0.0L};
+    real tau = 1.0L;
     bool isContinuous = false;
     bool isHappening = false;
     /**
@@ -522,8 +523,8 @@ class PropSimulation {
     /**
      * @brief Add an ejecta event to the simulation.
      */
-    void add_event(IntegBody body, real tEvent, std::vector<real> deltaV,
-                   real multiplier, real dt);
+    void add_event(IntegBody body, real tEvent, std::vector<real> expAccel0,
+                   real multiplier, real tau);
     /**
      * @brief Set the values of the PropSimulation Constants object.
      */

src/force.cpp

@@ -657,24 +657,16 @@ static void force_continuous_event(const real &t, const PropSimulation *propSim,
             if (propSim->eventMngr.continuousEvents[i].isHappening){
                 const size_t starti =
                     propSim->eventMngr.continuousEvents[i].xIntegIndex / 2;
-                const real tPastEvent =
-                    t - propSim->eventMngr.continuousEvents[i].t;
-                // f = np.sin(np.pi*x/(2*time_for_val))
-                // df = np.pi/(2*time_for_val)*np.cos(np.pi*x/(2*time_for_val))
-                const real preFac =
-                    PI / (2 * propSim->eventMngr.continuousEvents[i].dt);
-                real accFac = preFac * cos(preFac * tPastEvent);
-                if (accFac > preFac || accFac < 0.0) {
-                    accFac = 0.0;
-                }
-                accInteg[starti + 0] += accFac *
-                    propSim->eventMngr.continuousEvents[i].deltaV[0] *
+                const real tPastEvent = t - propSim->eventMngr.continuousEvents[i].t;
+                const real postFac = exp(-tPastEvent/propSim->eventMngr.continuousEvents[i].tau);
+                accInteg[starti + 0] += propSim->eventMngr.continuousEvents[i].expAccel0[0] *
+                    postFac *
                     propSim->eventMngr.continuousEvents[i].multiplier * propDir;
-                accInteg[starti + 1] += accFac *
-                    propSim->eventMngr.continuousEvents[i].deltaV[1] *
+                accInteg[starti + 1] += propSim->eventMngr.continuousEvents[i].expAccel0[1] *
+                    postFac *
                     propSim->eventMngr.continuousEvents[i].multiplier * propDir;
-                accInteg[starti + 2] += accFac *
-                    propSim->eventMngr.continuousEvents[i].deltaV[2] *
+                accInteg[starti + 2] += propSim->eventMngr.continuousEvents[i].expAccel0[2] *
+                    postFac *
                     propSim->eventMngr.continuousEvents[i].multiplier * propDir;
             }
         }

src/gr15.cpp

@@ -255,14 +255,12 @@ void check_continuous_events(PropSimulation *propSim, const real &t) {
         bool allDone = true;
         bool forwardProp = propSim->integParams.tf > propSim->integParams.t0;
         for (size_t i = 0; i < propSim->eventMngr.nConEvents; i++) {
-            // const bool eventStarted = t >= propSim->eventMngr.continuousEvents[i].t;
-            // const bool eventEnded = t > propSim->eventMngr.continuousEvents[i].t + propSim->eventMngr.continuousEvents[i].dt;
             bool eventStarted, eventEnded;
             if (forwardProp) {
                 eventStarted = t >= propSim->eventMngr.continuousEvents[i].t;
-                eventEnded = t >= (propSim->eventMngr.continuousEvents[i].t + propSim->eventMngr.continuousEvents[i].dt);
+                eventEnded = t >= propSim->integParams.tf;
             } else {
-                eventStarted = t <= (propSim->eventMngr.continuousEvents[i].t + propSim->eventMngr.continuousEvents[i].dt);
+                eventStarted = t <= propSim->integParams.t0;
                 eventEnded = t < propSim->eventMngr.continuousEvents[i].t;
             }
             if (eventStarted && !eventEnded) {
@@ -306,17 +304,12 @@ void event_timestep_check(PropSimulation *propSim, real &dt) {
         }
     }
     if (!propSim->eventMngr.allConEventDone) {
-        for (size_t i = 0; i < propSim->eventMngr.nConEvents; i++) {
-            if (propSim->eventMngr.continuousEvents[i].isHappening) {
-                // if any continuous event is happening, set dt to 1/10th of the event duration
-                // dt is the min of the current dt and the one dictated by the event
-                dt = fmin(1.0, propSim->eventMngr.continuousEvents[i].dt/10.0L);
-                dt = forwardProp ? dt : -dt;
-            }
-            if (forwardProp && propSim->t < propSim->eventMngr.continuousEvents[i].t) {
-                tNextEvent = fmin(tNextEvent, propSim->eventMngr.continuousEvents[i].t);
-            } else if (!forwardProp && propSim->t > propSim->eventMngr.continuousEvents[i].t+propSim->eventMngr.continuousEvents[i].dt) {
-                tNextEvent = fmax(tNextEvent, propSim->eventMngr.continuousEvents[i].t+propSim->eventMngr.continuousEvents[i].dt);
+        for (size_t i = 0; i < propSim->eventMngr.nConEvents; i++) { 
+            const real tNextConEvent = propSim->eventMngr.continuousEvents[i].t;
+            if (forwardProp && propSim->t < tNextConEvent) {
+                tNextEvent = fmin(tNextEvent, tNextConEvent);
+            } else if (!forwardProp && propSim->t > tNextConEvent) {
+                tNextEvent = fmax(tNextEvent, tNextConEvent);
             }
         }
     }

src/grss.cpp

@@ -884,8 +884,8 @@ PYBIND11_MODULE(libgrss, m) {
              static_cast<void (PropSimulation::*)(
                  IntegBody, real, std::vector<real>, real, real)>(
                  &PropSimulation::add_event),
-             py::arg("bodyName"), py::arg("tEvent"), py::arg("deltaV"),
-             py::arg("multiplier"), py::arg("dt"),
+             py::arg("bodyName"), py::arg("tEvent"), py::arg("expAccel0"),
+             py::arg("multiplier"), py::arg("tau"),
              R"mydelimiter(
              Adds an ejecta event to the simulation.
 
@@ -895,12 +895,12 @@ PYBIND11_MODULE(libgrss, m) {
                 Name of the body to apply the delta-V to.
             tEvent : real
                 MJD Epoch of the event. Must be in TDB.
-            deltaV : list of real
-                Delta-V to apply to the body.
+            expAccel0 : list of real
+                Initial exponentiallly decaying acceleration.
             multiplier : real
-                Multiplier to apply to the delta-V.
-            dt : real
-                Time duration for the continuous ejecta event.
+                Multiplier for the exponential decay.
+            tau : real
+                Time constant for the exponentiallly decaying acceleration.
             )mydelimiter")
         .def("set_sim_constants", &PropSimulation::set_sim_constants,
              py::arg("du2m") = 149597870700.0L, py::arg("tu2s") = 86400.0L,

src/simulation.cpp

@@ -1060,7 +1060,7 @@ void PropSimulation::add_event(IntegBody body, real tEvent,
     event.deltaV = deltaV;
     event.multiplier = multiplier;
 
-    event.dt = 0.0;
+    event.tau = 0.0;
     event.isContinuous = false;
     event.isHappening = false;
     event_postprocess(this, event);
@@ -1070,22 +1070,23 @@ void PropSimulation::add_event(IntegBody body, real tEvent,
 /**
  * @param[in] body IntegBody object to apply the EjectaEvent to.
  * @param[in] tEvent Time at which to apply the EjectaEvent.
- * @param[in] deltaV Delta-V for the ejecta.
- * @param[in] multiplier Multiplier for the Delta-V.
- * @param[in] dt Time duration for the ejecta.
+ * @param[in] expAccel0 Initial exponentiallly decaying acceleration.
+ * @param[in] multiplier Multiplier for the exponential decay.
+ * @param[in] tau Time constant for the exponentiallly decaying acceleration.
  */
 void PropSimulation::add_event(IntegBody body, real tEvent,
-                               std::vector<real> deltaV, real multiplier,
-                               real dt) {
+                               std::vector<real> expAccel0, real multiplier,
+                               real tau) {
     size_t bodyIndex = event_preprocess(this, body, tEvent);
     Event event;
     event.t = tEvent;
     event.bodyName = body.name;
     event.bodyIndex = bodyIndex;
-    event.deltaV = deltaV;
+    event.deltaV = std::vector<real>(3, 0.0);
     event.multiplier = multiplier;
 
-    event.dt = dt;
+    event.expAccel0 = expAccel0;
+    event.tau = tau;
     event.isContinuous = true;
     event.isHappening = false;
     event_postprocess(this, event);