fix duplicate figure object in latest matplotlib

Author: zingale

pyro/incompressible/simulation.py

@@ -427,7 +427,7 @@ def dovis(self):
             0.5*(u.ip(1) - u.ip(-1))/myg.dx + \
             0.5*(v.jp(1) - v.jp(-1))/myg.dy
 
-        _, axes = plt.subplots(nrows=2, ncols=2, num=1)
+        _, axes = plt.subplots(nrows=2, ncols=2, num=1, clear=True)
         plt.subplots_adjust(hspace=0.25)
 
         fields = [u, v, vort, divU]

pyro/lm_atm/simulation.py

@@ -643,7 +643,7 @@ def dovis(self):
 
         vort.v()[:, :] = dv - du
 
-        _, axes = plt.subplots(nrows=2, ncols=2, num=1)
+        _, axes = plt.subplots(nrows=2, ncols=2, num=1, clear=True)
         plt.subplots_adjust(hspace=0.25)
 
         fields = [rho, magvel, vort, rhoprime]