Allow subgrids to inherit any time step stability factor. Remove get_src function (not used).

gprMax/cmds_singleuse.py

@@ -189,7 +189,9 @@ class TimeStepStabilityFactor(UserObjectSingle):
             logger.exception(f'{self.__str__()} requires the value of the time '
                              f'step stability factor to be between zero and one')
             raise ValueError
-        G.dt = G.dt * f
+        
+        G.dt_mod = f
+        G.dt = G.dt * G.dt_mod
 
         logger.info(f'Time step (modified): {G.dt:g} secs')
 

gprMax/geometry_outputs.py

@@ -287,7 +287,8 @@ class Comments():
             # Information on PML thickness
             if self.grid.pmls['slabs']:
                 comments['PMLthickness'] = self.pml_gv_comment()
-            srcs = self.grid.get_srcs()
+            srcs = (self.grid.hertziandipoles + self.grid.magneticdipoles + 
+                   self.grid.voltagesources + self.grid.transmissionlines)
             if srcs:
                 comments['Sources'] = self.srcs_rx_gv_comment(srcs)
             if self.grid.rxs:

gprMax/grid.py

@@ -46,8 +46,9 @@ class FDTDGrid:
         self.dy = 0
         self.dz = 0
         self.dt = 0
-        self.iteration = 0
-        self.iterations = 0
+        self.dt_mod = None # Time step stability factor
+        self.iteration = 0 # Current iteration number
+        self.iterations = 0 # Total number of iterations
         self.timewindow = 0
 
         # PML parameters - set some defaults to use if not user provided
@@ -297,9 +298,6 @@ class FDTDGrid:
         # hardware maximum. Avoids inadvertently exceeding the CFL due to
         # binary representation of floating point number.
         self.dt = round_value(self.dt, decimalplaces=d.getcontext().prec - 1)
-    
-    def get_srcs(self):
-        return self.hertziandipoles + self.magneticdipoles + self.voltagesources + self.transmissionlines
 
 
 class CUDAGrid(FDTDGrid):

gprMax/subgrids/user_objects.py

@@ -54,7 +54,7 @@ class SubGridBase(UserObjectMulti):
         sg.dz = grid.dz / sg.ratio
         sg.dl = np.array([sg.dx, sg.dy, sg.dz])
 
-    def set_main_grid_indices(self, sg, grid, uip, p1, p2):
+    def set_main_grid_indices(self, sg, uip, p1, p2):
         """Sets subgrid indices related to main grid placement."""
         # Location of the IS
         sg.i0, sg.j0, sg.k0 = p1
@@ -91,11 +91,14 @@ class SubGridBase(UserObjectMulti):
 
         self.set_discretisation(sg, grid)
 
-        # Set the temporal discretisation
+        # Set temporal discretisation including inheriting any time step 
+        # stability factor from the main grid
         sg.calculate_dt()
+        if sg.dt_mod:
+            sg.dt = sg.dt * sg.dt_mod
 
         # Set the indices related to the subgrids main grid placement
-        self.set_main_grid_indices(sg, grid, uip, p1, p2)
+        self.set_main_grid_indices(sg, uip, p1, p2)
 
         """
         try: