Index: gpaw/blacs.py
===================================================================
--- gpaw/blacs.py	(revision 7232)
+++ gpaw/blacs.py	(working copy)
@@ -197,6 +197,18 @@
             _gpaw.blacs_destroy(self.context)
 
 
+class DryRunBlacsGrid(BlacsGrid):
+    def __init__(self, comm, nprow, npcol, order='R'):
+        assert isinstance(comm, SerialCommunicator) #DryRunCommunicator is subclass
+        self.context = INACTIVE
+        self.comm = comm
+        self.nprow = nprow
+        self.npcol = npcol
+        self.ncpus = nprow * npcol
+        self.mycol, self.myrow = nprow / comm.size, npcol / comm.size #XXX float round-off
+        self.order = order
+
+
 class BlacsDescriptor(MatrixDescriptor):
     """Class representing a 2D matrix distribution on a blacs grid.