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diff --git a/src/MPIO.slow.hh b/src/MPIO.slow.hh
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+#ifndef __MPIO_HH_
+#define __MPIO_HH_
+#include "IO.hh"
+#include "MPIutils.hh"
+#include "Timer.H"
+
+/* Simplifies assumptions about domain decomposition */ 
+/*
+  Module: MPIO
+
+  Description:
+  Implements slice-based Parallel IO for IEEEIO libraries.
+  Uses iSend/iRecv of XY slices to hide message passing latency.
+  This is a simplified version of PIO which makes fewer assumptions
+  about the layout of the data.
+  
+  Will eventually be subclassed from IObase so that you can
+  drop-in replace a single-threaded IO system with this
+  multithreaded one.  writeChunk() will be used to announce
+  the local chunks and perform the write in parallel rather
+  than collecting serially.
+  
+  Needs to have extensions to automatically remove ghost zones
+  setLocalDims(origin,dims,minindex,maxindex)
+
+  Limitations:
+  * currently only works for 3D grids
+  * only understands Float32 and Float64 datatypes
+  * Assumes HPF layout (eg, canonical processor layout where
+    all PE's are aligned to grid... no partial overlaps)
+  * Uses XY slices (assumes fortran ordering for dimensions)
+  * Collects only to a single file (cannot do a multi-gather).
+ */
+class MPIO /* : public IObase */ {
+  int *gdims,*gorigins,grank;
+  MPIcomm &comm;
+  int globaldims[3]; // for master
+  int localorigin[3],localdims[3];
+  int root,myid;
+  IObase *file;
+  Timer slicewait,slicewrite,slicecollect,sliceselect;
+  Timer sliceallwait;
+  inline int isRoot(){ return ((myid == root)?1:0);}
+  // MPI_Request *slice_send_requests;
+protected:
+  void sendSlice(int z,float *data,MPI_Request *req);
+  void requestSlice(int z,float *slicebuffer,MPI_Request *req);
+  void waitForSlice(int z,float *slicebuffer,float *destbuffer,MPI_Request *req);
+public:
+  MPIO(IObase *io,MPIcomm &c);
+  ~MPIO();
+  void setLocalDims(int rank,int *origin, int *dims);
+  virtual int write(IObase::DataType type,int rank,int *dims,void *data);
+  void write(float *data);
+};
+
+#endif // __MPIO_HH_