Data Flow Graph construction - 2023.2 English

Once AIE kernels have been prepared, next step is to create a Data Flow Graph class which defines the top level ports, Run time parameters, connectivity, constraints etc. This consists of below steps

1. Create graph.h and include Adaptive Data Flow (ADF) header file (adf.h). Also include header file with kernel function prototypes (kernel.h)

   #include <adf.h>
   #include "kernels.h"
   

2. Define your graph class by using the objects which are defined in the adf name space. All user graphs are derived from the class graph.

   include <adf.h>
   #include "kernels.h"
   
   using namespace adf;
   
   class myGraph : public graph {
   private:
       kernel k1;
   };
   

3. Add top level ports to graph. These ports will be responsible to data transfers to / from the kernels.

   #include <adf.h>
   #include "kernels.h"
   
   using namespace adf;
   
   class simpleGraph : public graph {
   private:
       kernel k1;
   
   public:
       port<input> inptr;
       port<output> outptr;
       port<input> kernelCoefficients;
   };
   

4. Specify connections of top level ports to kernels. Primary connections type are Window, Stream, Run time parameters. Below is example code specifying connectivity.

   class myGraph : public adf::graph {
   private:
       kernel k1;
   public:
       port<input> inptr;
       port<output> outptr;
       port<input> kernelCoefficients;
   
       myGraph() {
           k1 = kernel::create(filter2D);
           adf::connect<window<TILE_WINDOW_SIZE> >(inptr, k1.in[0]);
           adf::connect<parameter>(kernelCoefficients, async(k1.in[1]));
           adf::connect<window<TILE_WINDOW_SIZE> >(k1.out[0], outptr);
       }
   };
   

5. Specify source file location and other constraints for each kernel

   class myGraph : public adf::graph {
   private:
       kernel k1;
   public:
       port<input> inptr;
       port<output> outptr;
       port<input> kernelCoefficients;
   
       myGraph() {
           k1 = kernel::create(filter2D);
           adf::connect<window<TILE_WINDOW_SIZE> >(inptr, k1.in[0]);
           adf::connect<parameter>(kernelCoefficients, async(k1.in[1]));
           adf::connect<window<TILE_WINDOW_SIZE> >(k1.out[0], outptr);
           source(k1) = "xf_filter2d.cc";
           // Initial mapping
           runtime<ratio>(k1) = 0.5;
       }
   };