simplify the conservative update as a loop

Author: Michael Zingale

compressible/simulation.py

@@ -179,6 +179,9 @@ def preevolve(self):
 
 
     def evolve(self, dt):
+        """
+        Evolve the equations of compressible hydrodynamics through a timestep dt
+        """
 
         pf = profile.timer("evolve")
         pf.begin()
@@ -201,46 +204,14 @@ def evolve(self, dt):
         dtdx = dt/myg.dx
         dtdy = dt/myg.dy
 
-        dens[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] += \
-           dtdx*(Flux_x[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.idens] - \
-                 Flux_x[myg.ilo+1:myg.ihi+2,
-                        myg.jlo  :myg.jhi+1,self.vars.idens]) + \
-           dtdy*(Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.idens] - \
-                 Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo+1:myg.jhi+2,self.vars.idens])    
-
-        xmom[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] += \
-           dtdx*(Flux_x[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.ixmom] - \
-                 Flux_x[myg.ilo+1:myg.ihi+2,
-                        myg.jlo  :myg.jhi+1,self.vars.ixmom]) + \
-           dtdy*(Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.ixmom] - \
-                 Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo+1:myg.jhi+2,self.vars.ixmom])    
-
-        ymom[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] += \
-           dtdx*(Flux_x[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.iymom] - \
-                 Flux_x[myg.ilo+1:myg.ihi+2,
-                        myg.jlo  :myg.jhi+1,self.vars.iymom]) + \
-           dtdy*(Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.iymom] - \
-                 Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo+1:myg.jhi+2,self.vars.iymom])    
-
-        ener[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] += \
-           dtdx*(Flux_x[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.iener] - \
-                 Flux_x[myg.ilo+1:myg.ihi+2,
-                        myg.jlo  :myg.jhi+1,self.vars.iener]) + \
-           dtdy*(Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo  :myg.jhi+1,self.vars.iener] - \
-                 Flux_y[myg.ilo  :myg.ihi+1,
-                        myg.jlo+1:myg.jhi+2,self.vars.iener])    
+        for n in range(self.vars.nvar):
+            var = self.cc_data.get_var_by_index(n)
 
+            var[myg.ilo:myg.ihi+1,myg.jlo:myg.jhi+1] += \
+                dtdx*(Flux_x[myg.ilo  :myg.ihi+1,myg.jlo  :myg.jhi+1,n] - \
+                      Flux_x[myg.ilo+1:myg.ihi+2,myg.jlo  :myg.jhi+1,n]) + \
+                dtdy*(Flux_y[myg.ilo  :myg.ihi+1,myg.jlo  :myg.jhi+1,n] - \
+                      Flux_y[myg.ilo  :myg.ihi+1,myg.jlo+1:myg.jhi+2,n])    
 
         # gravitational source terms
         ymom += 0.5*dt*(dens + old_dens)*grav

mesh/patch.py

@@ -486,6 +486,26 @@ def get_var(self, name):
         n = self.vars.index(name)
         return self.data[n,:,:]
 
+
+    def get_var_by_index(self, n):
+        """
+        Return a data array for the variable with index n in the 
+        data array.  Any changes made to this are automatically 
+        reflected in the CellCenterData2d object.
+
+        Parameters
+        ----------
+        n : int
+            The index of the variable to access
+
+        Returns
+        -------
+        out : ndarray
+            The array of data corresponding to the index
+
+        """
+        return self.data[n,:,:]
+
 
     def get_aux(self, keyword):
         """