make the RT problem initial conditions symmetric (#216)

this reduces roundoff
python-hydro · Aug 31, 2024 · e9df7b2 · e9df7b2
1 parent a8415d3
commit e9df7b2
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/pyro/compressible/problems/rt.py b/pyro/compressible/problems/rt.py
@@ -59,8 +59,9 @@ def init_data(my_data, rp):
 
         j += 1
 
-    ymom[:, :] = amp*np.cos(2.0*np.pi*myg.x2d/(myg.xmax-myg.xmin))*np.exp(-(myg.y2d-ycenter)**2/sigma**2)
-
+    L = myg.xmax-myg.xmin
+    ymom[:, :] = amp * 0.5 * (np.cos(2.0*np.pi*myg.x2d/L) +
+                              np.cos(2.0*np.pi*(L - myg.x2d)/L)) * np.exp(-(myg.y2d-ycenter)**2/sigma**2)
     ymom *= dens
 
     # set the energy (P = cs2*dens)