From 0021b72da97631139e38d0d8e82e30ee2fdb1a65 Mon Sep 17 00:00:00 2001
From: Peter Boyle <paboyle@ph.ed.ac.uk>
Date: Wed, 4 Mar 2015 05:33:26 +0000
Subject: [PATCH] Update organisation

---
 Grid_Cartesian.h | 79 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/Grid_Cartesian.h b/Grid_Cartesian.h
index 779cf44f..03044bdd 100644
--- a/Grid_Cartesian.h
+++ b/Grid_Cartesian.h
@@ -1,7 +1,83 @@
+#ifndef GRID_CARTESIAN_H
+#define GRID_CARTESIAN_H
+
 #include "Grid.h"
-#include "Grid_vComplexD.h"
 
 namespace dpo{
+
+    
+/////////////////////////////////////////////////////////////////////////////////////////
+// Grid Support. Following will go into Grid.h.
+/////////////////////////////////////////////////////////////////////////////////////////
+    // Cartesian grids
+    // dpo::Grid
+    // dpo::GridCartesian
+    // dpo::GridCartesianRedBlack
+    
+class Grid {
+public:
+    // Give Lattice access
+    template<class object> friend class Lattice;
+
+        
+//protected:
+        
+    // Lattice wide random support. not yet fully implemented. Need seed strategy
+    // and one generator per site.
+    //std::default_random_engine generator;
+  //    static std::mt19937  generator( 9 );
+
+        
+    // Grid information.
+    unsigned long _ndimension;
+    std::vector<int> _layout;     // Which dimensions get relayed out over simd lanes.
+    std::vector<int> _dimensions; // Dimensions of array
+    std::vector<int> _rdimensions;// Reduced dimensions with simd lane images removed
+    std::vector<int> _ostride;    // Outer stride for each dimension
+    std::vector<int> _istride;    // Inner stride i.e. within simd lane
+    int _osites;                  // _isites*_osites = product(dimensions).
+    int _isites;
+        
+    // subslice information
+    std::vector<int> _slice_block;
+    std::vector<int> _slice_stride;
+    std::vector<int> _slice_nblock;
+public:
+    
+    // These routines are key. Subdivide the linearised cartesian index into
+    //      "inner" index identifying which simd lane of object<vFcomplex> is associated with coord
+    //      "outer" index identifying which element of _odata in class "Lattice" is associated with coord.
+    // Compared to, say, Blitz++ we simply need to store BOTH an inner stride and an outer
+    // stride per dimension. The cost of evaluating the indexing information is doubled for an n-dimensional
+    // coordinate. Note, however, for data parallel operations the "inner" indexing cost is not paid and all
+    // lanes are operated upon simultaneously.
+    
+    inline int oIndexReduced(std::vector<int> &rcoor)
+    {
+        int idx=0;
+        for(int d=0;d<_ndimension;d++) idx+=_ostride[d]*rcoor[d];
+        return idx;
+    }
+    virtual int oIndex(std::vector<int> &coor)
+    {
+        int idx=0;
+        for(int d=0;d<_ndimension;d++) idx+=_ostride[d]*(coor[d]%_rdimensions[d]);
+        return idx;
+    }
+    inline int iIndex(std::vector<int> &rcoor)
+    {
+        int idx=0;
+        for(int d=0;d<_ndimension;d++) idx+=_istride[d]*(rcoor[d]/_rdimensions[d]);
+        return idx;
+    }
+        
+    inline int oSites(void) { return _osites; };
+    inline int iSites(void) { return _isites; };
+    virtual int CheckerBoard(std::vector<int> site)=0;
+    virtual int CheckerBoardDestination(int source_cb,int shift)=0;
+    virtual int CheckerBoardShift(int source_cb,int dim,int shift)=0;
+};
+
 class GridCartesian: public Grid {
 public:
     virtual int CheckerBoard(std::vector<int> site){
@@ -176,3 +252,4 @@ protected:
 };
 
 }
+#endif