diff --git a/garlic/apps/creams/gen_grid.py b/garlic/apps/creams/gen_grid.py
new file mode 100755
index 00000000..723988b8
--- /dev/null
+++ b/garlic/apps/creams/gen_grid.py
@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+
+import argparse
+
+parser = argparse.ArgumentParser(description="Generate a grid.dat input file for CREAMS")
+
+parser.add_argument('--npx', type=int, help='number of processes in X', default=1)
+parser.add_argument('--npy', type=int, help='number of processes in Y', default=1)
+parser.add_argument('--npz', type=int, help='number of processes in Z', default=32)
+parser.add_argument('--grain', type=int, help='granularity', default=9)
+parser.add_argument('--nx', type=int, help='number of points in X', default=20)
+parser.add_argument('--ny', type=int, help='number of points in Y', default=20)
+parser.add_argument('--nz', type=int, help='number of points in Z', default=7000)
+parser.add_argument('--dx', type=float, help='grid spacing in X', default=0.0025062657)
+parser.add_argument('--dy', type=float, help='grid spacing in Y', default=0.0025062657)
+parser.add_argument('--dz', type=float, help='grid spacing in Z', default=0.0025062657)
+
+args = parser.parse_args()
+
+grain_str = "%d %d" % (args.grain, args.grain)
+boundary = "extrapolation"
+
+# Print
+print(' %-49d number of processes in x-direction (0 if automatic)' % args.npx)
+print(' %-49d number of processes in y-direction (0 if automatic)' % args.npy)
+print(' %-49d number of processes in z-direction (0 if automatic)' % args.npz)
+print(' ')
+print(' %-49s subdomain granularity' % grain_str)
+print(' ')
+print(' %-49s -x boundary' % boundary)
+print(' %-49s +x boundary' % boundary)
+print(' %-49s -y boundary' % boundary)
+print(' %-49s +y boundary' % boundary)
+print(' %-49s -z boundary' % boundary)
+print(' %-49s +z boundary' % boundary)
+print(' ')
+print(' x-direction')
+for i in range(args.nx):
+    print("%.9e" % (i * args.dx))
+print(' ')
+print(' y-direction')
+for i in range(args.ny):
+    print("%.9e" % (i * args.dy))
+print(' ')
+print(' z-direction')
+for i in range(args.nz):
+    print("%.9e" % (i * args.dz))
+print(' ')
+print(' END')
diff --git a/garlic/apps/creams/input.nix b/garlic/apps/creams/input.nix
index 1749a722..5a12f91a 100644
--- a/garlic/apps/creams/input.nix
+++ b/garlic/apps/creams/input.nix
@@ -1,7 +1,13 @@
 {
   stdenv
-, granul ? 0
-, nprocz ? 0
+, python3
+, granul ? 9
+, nprocx ? 1
+, nprocy ? 1
+, nprocz ? 1
+, nx ? 20
+, ny ? 20
+, nz ? 7000
 , gitBranch ? "garlic/mpi+send+seq"
 , gitCommit ? null
 , garlicTools
@@ -13,26 +19,30 @@ let
     inherit gitCommit gitBranch;
     gitTable = import ./git-table.nix;
   };
+
+  gen = ./gen_grid.py;
 in
   stdenv.mkDerivation rec {
     name = "creams-input";
 
+    buildInputs = [ python3 ];
+
     inherit (gitSource) src gitBranch gitCommit;
 
-    phases = [ "unpackPhase" "patchPhase" "installPhase" ];
-
-    patchPhase = ''
-      patchShebangs SodTubeBenchmark/gridScript.sh
-    '';
+    phases = [ "unpackPhase" "installPhase" ];
 
     installPhase = ''
-      pushd SodTubeBenchmark
-        ./gridScript.sh 0 0 ${toString nprocz} ${toString granul}
-      popd
-
       mkdir -p $out
       cp -a SodTubeBenchmark $out/
-    '';
 
-    hardeningDisable = [ "all" ];
+      python3 ${gen} \
+        --npx ${toString nprocx} \
+        --npy ${toString nprocy} \
+        --npz ${toString nprocz} \
+        --grain ${toString granul} \
+        --nx ${toString nx} \
+        --ny ${toString ny} \
+        --nz ${toString nz} \
+        > $out/SodTubeBenchmark/grid.dat
+    '';
   }