diff --git a/pyro/advection/problems/smooth.py b/pyro/advection/problems/smooth.py
index 3a62c92f7..b941c9a6a 100644
--- a/pyro/advection/problems/smooth.py
+++ b/pyro/advection/problems/smooth.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.smooth"
@@ -16,12 +13,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the smooth advection problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in smooth.py")
-        print(my_data.__class__)
-        sys.exit()
-
     dens = my_data.get_var("density")
 
     xmin = my_data.grid.xmin
diff --git a/pyro/advection/problems/test.py b/pyro/advection/problems/test.py
index ec60c4eaf..59229ff88 100644
--- a/pyro/advection/problems/test.py
+++ b/pyro/advection/problems/test.py
@@ -1,7 +1,3 @@
-import sys
-
-from pyro.mesh import patch
-
 DEFAULT_INPUTS = None
 
 PROBLEM_PARAMS = {}
@@ -11,12 +7,6 @@ def init_data(my_data, rp):
     """ an init routine for unit testing """
     del rp  # this problem doesn't use runtime params
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in sedov.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
 
diff --git a/pyro/advection/problems/tophat.py b/pyro/advection/problems/tophat.py
index 9d39f35c0..b108d6119 100644
--- a/pyro/advection/problems/tophat.py
+++ b/pyro/advection/problems/tophat.py
@@ -1,6 +1,3 @@
-import sys
-
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.tophat"
@@ -14,12 +11,6 @@ def init_data(myd, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the tophat advection problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(myd, patch.CellCenterData2d):
-        print("ERROR: patch invalid in tophat.py")
-        print(myd.__class__)
-        sys.exit()
-
     dens = myd.get_var("density")
 
     xmin = myd.grid.xmin
diff --git a/pyro/advection_nonuniform/problems/slotted.py b/pyro/advection_nonuniform/problems/slotted.py
index a48418cf5..17c4ae922 100755
--- a/pyro/advection_nonuniform/problems/slotted.py
+++ b/pyro/advection_nonuniform/problems/slotted.py
@@ -1,6 +1,5 @@
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.slotted"
@@ -15,11 +14,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the slotted advection problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in slotted.py")
-
     offset = rp.get_param("slotted.offset")
     omega = rp.get_param("slotted.omega")
 
diff --git a/pyro/advection_nonuniform/problems/test.py b/pyro/advection_nonuniform/problems/test.py
index 0a74a17c4..f99f6c860 100755
--- a/pyro/advection_nonuniform/problems/test.py
+++ b/pyro/advection_nonuniform/problems/test.py
@@ -1,6 +1,3 @@
-from pyro.mesh import patch
-from pyro.util import msg
-
 DEFAULT_INPUTS = None
 
 PROBLEM_PARAMS = {}
@@ -10,11 +7,6 @@ def init_data(my_data, rp):
     """ an init routine for unit testing """
     del rp  # this problem doesn't use runtime params
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in slotted.py")
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
 
diff --git a/pyro/burgers/problems/converge.py b/pyro/burgers/problems/converge.py
index eae07e997..5b7bf2500 100644
--- a/pyro/burgers/problems/converge.py
+++ b/pyro/burgers/problems/converge.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.converge.64"
@@ -14,12 +11,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the smooth burgers convergence problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in converge.py")
-        print(my_data.__class__)
-        sys.exit()
-
     u = my_data.get_var("x-velocity")
     v = my_data.get_var("y-velocity")
 
diff --git a/pyro/burgers/problems/test.py b/pyro/burgers/problems/test.py
index 339f0ce85..97dbd7b4c 100644
--- a/pyro/burgers/problems/test.py
+++ b/pyro/burgers/problems/test.py
@@ -1,6 +1,3 @@
-import sys
-
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.test"
@@ -14,12 +11,6 @@ def init_data(myd, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the burgers test problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(myd, patch.CellCenterData2d):
-        print("ERROR: patch invalid in test.py")
-        print(myd.__class__)
-        sys.exit()
-
     u = myd.get_var("x-velocity")
     v = myd.get_var("y-velocity")
 
diff --git a/pyro/burgers/problems/tophat.py b/pyro/burgers/problems/tophat.py
index d3371e17a..12bc595d3 100644
--- a/pyro/burgers/problems/tophat.py
+++ b/pyro/burgers/problems/tophat.py
@@ -1,6 +1,3 @@
-import sys
-
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.tophat"
@@ -12,12 +9,6 @@ def init_data(myd, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the tophat burgers problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(myd, patch.CellCenterData2d):
-        print("ERROR: patch invalid in tophat.py")
-        print(myd.__class__)
-        sys.exit()
-
     u = myd.get_var("x-velocity")
     v = myd.get_var("y-velocity")
 
diff --git a/pyro/compressible/problems/acoustic_pulse.py b/pyro/compressible/problems/acoustic_pulse.py
index b57a28589..3e00bb05e 100644
--- a/pyro/compressible/problems/acoustic_pulse.py
+++ b/pyro/compressible/problems/acoustic_pulse.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import fv, patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.acoustic_pulse"
@@ -18,12 +15,6 @@ def init_data(myd, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the acoustic pulse problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(myd, (patch.CellCenterData2d, fv.FV2d)):
-        print("ERROR: patch invalid in acoustic_pulse.py")
-        print(myd.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = myd.get_var("density")
     xmom = myd.get_var("x-momentum")
diff --git a/pyro/compressible/problems/advect.py b/pyro/compressible/problems/advect.py
index 9a586f5ba..516ec71e8 100644
--- a/pyro/compressible/problems/advect.py
+++ b/pyro/compressible/problems/advect.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.advect.64"
@@ -16,12 +13,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the advect problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in advect.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/bubble.py b/pyro/compressible/problems/bubble.py
index 1a81cfaef..bc72676f9 100644
--- a/pyro/compressible/problems/bubble.py
+++ b/pyro/compressible/problems/bubble.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.bubble"
@@ -22,12 +19,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the bubble problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in bubble.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/gresho.py b/pyro/compressible/problems/gresho.py
index a3ff4429b..a11af9e39 100644
--- a/pyro/compressible/problems/gresho.py
+++ b/pyro/compressible/problems/gresho.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.gresho"
@@ -19,12 +16,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the Gresho vortex problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("Error: patch invalid in gresho.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density and velocities
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/hse.py b/pyro/compressible/problems/hse.py
index d3657a211..4d50b9d83 100644
--- a/pyro/compressible/problems/hse.py
+++ b/pyro/compressible/problems/hse.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.hse"
@@ -17,12 +14,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the HSE problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in hse.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/kh.py b/pyro/compressible/problems/kh.py
index bbf32fb36..191d3b434 100644
--- a/pyro/compressible/problems/kh.py
+++ b/pyro/compressible/problems/kh.py
@@ -1,6 +1,5 @@
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.kh"
@@ -18,11 +17,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the Kelvin-Helmholtz problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in kh.py")
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/logo.py b/pyro/compressible/problems/logo.py
index 8aa5ee25c..8f27c263a 100644
--- a/pyro/compressible/problems/logo.py
+++ b/pyro/compressible/problems/logo.py
@@ -1,9 +1,6 @@
-import sys
-
 import matplotlib.pyplot as plt
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.logo"
@@ -17,12 +14,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the logo problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in logo.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # create the logo
     myg = my_data.grid
 
diff --git a/pyro/compressible/problems/quad.py b/pyro/compressible/problems/quad.py
index ab3b213d4..ffbe38840 100644
--- a/pyro/compressible/problems/quad.py
+++ b/pyro/compressible/problems/quad.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.quad"
@@ -41,12 +38,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the quadrant problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in quad.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/ramp.py b/pyro/compressible/problems/ramp.py
index 081e63df0..55d872344 100644
--- a/pyro/compressible/problems/ramp.py
+++ b/pyro/compressible/problems/ramp.py
@@ -1,9 +1,7 @@
 import math
-import sys
 
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.ramp"
@@ -29,12 +27,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the double Mach reflection problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in ramp.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/rt.py b/pyro/compressible/problems/rt.py
index efd31ce90..f22dec200 100644
--- a/pyro/compressible/problems/rt.py
+++ b/pyro/compressible/problems/rt.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.rt"
@@ -20,12 +17,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the rt problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in rt.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/rt2.py b/pyro/compressible/problems/rt2.py
index 612a0d19f..b738f347e 100644
--- a/pyro/compressible/problems/rt2.py
+++ b/pyro/compressible/problems/rt2.py
@@ -3,11 +3,8 @@
 how the growth rate depends on wavenumber.
 """
 
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.rt2"
@@ -25,12 +22,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the rt problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in rt2.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/sedov.py b/pyro/compressible/problems/sedov.py
index d3f9888e3..cafd1591a 100644
--- a/pyro/compressible/problems/sedov.py
+++ b/pyro/compressible/problems/sedov.py
@@ -1,9 +1,7 @@
 import math
-import sys
 
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.sedov"
@@ -18,12 +16,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the sedov problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in sedov.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible/problems/sod.py b/pyro/compressible/problems/sod.py
index 1da25b732..23ca97b5d 100644
--- a/pyro/compressible/problems/sod.py
+++ b/pyro/compressible/problems/sod.py
@@ -1,6 +1,3 @@
-import sys
-
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.sod.x"
@@ -20,12 +17,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the sod problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in sod.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the sod parameters
     dens_left = rp.get_param("sod.dens_left")
     dens_right = rp.get_param("sod.dens_right")
diff --git a/pyro/compressible/problems/test.py b/pyro/compressible/problems/test.py
index 1a561e22c..b2b5b2bf2 100644
--- a/pyro/compressible/problems/test.py
+++ b/pyro/compressible/problems/test.py
@@ -1,7 +1,3 @@
-import sys
-
-from pyro.mesh import patch
-
 DEFAULT_INPUTS = None
 
 PROBLEM_PARAMS = {}
@@ -11,12 +7,6 @@ def init_data(my_data, rp):
     """ an init routine for unit testing """
     del rp  # this problem doesn't use runtime params
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in sedov.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible_react/problems/flame.py b/pyro/compressible_react/problems/flame.py
index 589c78ca3..3ee41b6fd 100644
--- a/pyro/compressible_react/problems/flame.py
+++ b/pyro/compressible_react/problems/flame.py
@@ -1,9 +1,7 @@
 import math
-import sys
 
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.flame"
@@ -16,12 +14,6 @@ def init_data(my_data, rp):
 
     msg.bold("initializing the flame problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in flame.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/compressible_react/problems/rt.py b/pyro/compressible_react/problems/rt.py
index beb181eb4..c51c1c73d 100644
--- a/pyro/compressible_react/problems/rt.py
+++ b/pyro/compressible_react/problems/rt.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.rt"
@@ -15,12 +12,6 @@ def init_data(my_data, rp):
 
     msg.bold("initializing the rt problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in rt.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     dens = my_data.get_var("density")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/diffusion/problems/gaussian.py b/pyro/diffusion/problems/gaussian.py
index 02cc5fc4a..5ab52a10b 100644
--- a/pyro/diffusion/problems/gaussian.py
+++ b/pyro/diffusion/problems/gaussian.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.gaussian"
@@ -25,12 +22,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the Gaussian diffusion problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in diffuse.py")
-        print(my_data.__class__)
-        sys.exit()
-
     phi = my_data.get_var("phi")
 
     xmin = my_data.grid.xmin
diff --git a/pyro/diffusion/problems/test.py b/pyro/diffusion/problems/test.py
index a410c2c66..b34c09a6d 100644
--- a/pyro/diffusion/problems/test.py
+++ b/pyro/diffusion/problems/test.py
@@ -1,7 +1,3 @@
-import sys
-
-from pyro.mesh import patch
-
 DEFAULT_INPUTS = None
 
 PROBLEM_PARAMS = {}
@@ -11,12 +7,6 @@ def init_data(my_data, rp):
     """ an init routine for unit testing """
     del rp  # this problem doesn't use runtime params
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in test.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density, momenta, and energy as separate variables
     phi = my_data.get_var("phi")
     phi[:, :] = 1.0
diff --git a/pyro/incompressible/problems/converge.py b/pyro/incompressible/problems/converge.py
index e13c006f5..6d1e810fa 100644
--- a/pyro/incompressible/problems/converge.py
+++ b/pyro/incompressible/problems/converge.py
@@ -28,7 +28,6 @@
 
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.converge.64"
@@ -42,11 +41,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the incompressible converge problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in converge.py")
-
     # get the velocities
     u = my_data.get_var("x-velocity")
     v = my_data.get_var("y-velocity")
diff --git a/pyro/incompressible/problems/shear.py b/pyro/incompressible/problems/shear.py
index 648b5f3a3..e2ce51da7 100644
--- a/pyro/incompressible/problems/shear.py
+++ b/pyro/incompressible/problems/shear.py
@@ -18,7 +18,6 @@
 
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.shear"
@@ -33,11 +32,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the incompressible shear problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in shear.py")
-
     # get the necessary runtime parameters
     rho_s = rp.get_param("shear.rho_s")
     delta_s = rp.get_param("shear.delta_s")
diff --git a/pyro/incompressible_viscous/problems/cavity.py b/pyro/incompressible_viscous/problems/cavity.py
index 7ad429c96..deaffaf7b 100644
--- a/pyro/incompressible_viscous/problems/cavity.py
+++ b/pyro/incompressible_viscous/problems/cavity.py
@@ -10,7 +10,6 @@
 https://www.fluid.tuwien.ac.at/HendrikKuhlmann?action=AttachFile&do=get&target=LidDrivenCavity.pdf
 """
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.cavity"
@@ -24,11 +23,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the lid-driven cavity problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in cavity.py")
-
     myg = my_data.grid
 
     if (myg.xmin != 0 or myg.xmax != 1 or
diff --git a/pyro/incompressible_viscous/problems/converge.py b/pyro/incompressible_viscous/problems/converge.py
index 2c07bd9fe..e968ec678 100644
--- a/pyro/incompressible_viscous/problems/converge.py
+++ b/pyro/incompressible_viscous/problems/converge.py
@@ -27,7 +27,6 @@
 
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.converge.64"
@@ -41,11 +40,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the incompressible viscous converge problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in converge.py")
-
     # get the velocities
     u = my_data.get_var("x-velocity")
     v = my_data.get_var("y-velocity")
diff --git a/pyro/incompressible_viscous/problems/shear.py b/pyro/incompressible_viscous/problems/shear.py
index 648b5f3a3..e2ce51da7 100644
--- a/pyro/incompressible_viscous/problems/shear.py
+++ b/pyro/incompressible_viscous/problems/shear.py
@@ -18,7 +18,6 @@
 
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.shear"
@@ -33,11 +32,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the incompressible shear problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in shear.py")
-
     # get the necessary runtime parameters
     rho_s = rp.get_param("shear.rho_s")
     delta_s = rp.get_param("shear.delta_s")
diff --git a/pyro/lm_atm/problems/bubble.py b/pyro/lm_atm/problems/bubble.py
index 2f0254d8a..abdb2b0b4 100644
--- a/pyro/lm_atm/problems/bubble.py
+++ b/pyro/lm_atm/problems/bubble.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.bubble"
@@ -22,12 +19,6 @@ def init_data(my_data, base, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the bubble problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in bubble.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density and velocities
     dens = my_data.get_var("density")
     xvel = my_data.get_var("x-velocity")
diff --git a/pyro/lm_atm/problems/gresho.py b/pyro/lm_atm/problems/gresho.py
index 274febce4..430461087 100644
--- a/pyro/lm_atm/problems/gresho.py
+++ b/pyro/lm_atm/problems/gresho.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.gresho"
@@ -21,12 +18,6 @@ def init_data(my_data, base, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the Gresho vortex problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in bubble.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the density and velocities
     dens = my_data.get_var("density")
     xvel = my_data.get_var("x-velocity")
diff --git a/pyro/swe/problems/acoustic_pulse.py b/pyro/swe/problems/acoustic_pulse.py
index a70599999..1deea825d 100644
--- a/pyro/swe/problems/acoustic_pulse.py
+++ b/pyro/swe/problems/acoustic_pulse.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.acoustic_pulse"
@@ -18,12 +15,6 @@ def init_data(myd, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the acoustic pulse problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(myd, patch.CellCenterData2d):
-        print("ERROR: patch invalid in acoustic_pulse.py")
-        print(myd.__class__)
-        sys.exit()
-
     # get the height, momenta as separate variables
     h = myd.get_var("height")
     xmom = myd.get_var("x-momentum")
diff --git a/pyro/swe/problems/advect.py b/pyro/swe/problems/advect.py
index b20921b64..ebf301eb1 100644
--- a/pyro/swe/problems/advect.py
+++ b/pyro/swe/problems/advect.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.advect"
@@ -16,12 +13,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the advect problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in advect.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the hity, momenta, and energy as separate variables
     h = my_data.get_var("height")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/swe/problems/dam.py b/pyro/swe/problems/dam.py
index c7e8a8a39..8c555feab 100644
--- a/pyro/swe/problems/dam.py
+++ b/pyro/swe/problems/dam.py
@@ -1,6 +1,3 @@
-import sys
-
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.dam.x"
@@ -18,12 +15,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the dam problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in dam.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the dam parameters
     h_left = rp.get_param("dam.h_left")
     h_right = rp.get_param("dam.h_right")
diff --git a/pyro/swe/problems/kh.py b/pyro/swe/problems/kh.py
index b5b18727a..5d63ab8e9 100644
--- a/pyro/swe/problems/kh.py
+++ b/pyro/swe/problems/kh.py
@@ -1,6 +1,5 @@
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.kh"
@@ -17,11 +16,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the Kelvin-Helmholtz problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print(my_data.__class__)
-        msg.fail("ERROR: patch invalid in kh.py")
-
     # get the heightity, momenta, and energy as separate variables
     height = my_data.get_var("height")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/swe/problems/logo.py b/pyro/swe/problems/logo.py
index a88347f9d..e653f25c6 100644
--- a/pyro/swe/problems/logo.py
+++ b/pyro/swe/problems/logo.py
@@ -1,9 +1,6 @@
-import sys
-
 import matplotlib.pyplot as plt
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.logo"
@@ -17,12 +14,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the logo problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in sedov.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # create the logo
     myg = my_data.grid
 
diff --git a/pyro/swe/problems/quad.py b/pyro/swe/problems/quad.py
index 336f488c3..e55eca26f 100644
--- a/pyro/swe/problems/quad.py
+++ b/pyro/swe/problems/quad.py
@@ -1,8 +1,5 @@
-import sys
-
 import numpy as np
 
-from pyro.mesh import patch
 from pyro.util import msg
 
 DEFAULT_INPUTS = "inputs.quad"
@@ -29,12 +26,6 @@ def init_data(my_data, rp):
     if rp.get_param("driver.verbose"):
         msg.bold("initializing the quadrant problem...")
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in quad.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the height, momenta, and energy as separate variables
     h = my_data.get_var("height")
     xmom = my_data.get_var("x-momentum")
diff --git a/pyro/swe/problems/test.py b/pyro/swe/problems/test.py
index eeffdc4b2..3ddf94761 100644
--- a/pyro/swe/problems/test.py
+++ b/pyro/swe/problems/test.py
@@ -1,7 +1,3 @@
-import sys
-
-from pyro.mesh import patch
-
 DEFAULT_INPTUS = None
 
 PROBLEM_PARAMS = {}
@@ -11,12 +7,6 @@ def init_data(my_data, rp):
     """ an init routine for unit testing """
     del rp  # this problem doesn't use runtime params
 
-    # make sure that we are passed a valid patch object
-    if not isinstance(my_data, patch.CellCenterData2d):
-        print("ERROR: patch invalid in sedov.py")
-        print(my_data.__class__)
-        sys.exit()
-
     # get the hity, momenta, and energy as separate variables
     h = my_data.get_var("height")
     xmom = my_data.get_var("x-momentum")