Added representations definitions for the HMC

lib/qcd/representations/adjoint.h

@@ -0,0 +1,61 @@
+/*
+ *	Policy classes for the HMC
+ *	Author: Guido Cossu
+*/	
+
+#ifndef ADJOINT_H
+#define ADJOINT_H
+
+
+namespace Grid {
+namespace QCD {
+
+/*
+* This is an helper class for the HMC
+* Should contain only the data for the adjoint representation
+* and the facility to convert from the fundamental -> adjoint
+*/
+
+template <int ncolour>
+class AdjointRep {
+ public:
+  typename SU_Adjoint<ncolour>::LatticeAdjMatrix U;
+  const int Dimension = ncolour * ncolour - 1;
+
+  explicit AdjointRep(GridBase* grid):U(grid) {}
+  void update_representation(const LatticeGaugeField& Uin) {
+    // Uin is in the fundamental representation
+    // get the U in AdjointRep
+    // (U_adj)_B = tr[e^a U e^b U^dag]
+    // e^a = t^a/sqrt(T_F)
+    // where t^a is the generator in the fundamental
+    // T_F is 1/2 for the fundamental representation
+    conformable(U, Uin);
+    U = zero;
+    LatticeGaugeField tmp(Uin._grid);
+
+    Vector<typename SU<ncolour>::Matrix > ta(ncolour * ncolour - 1);
+
+    // FIXME probably not very efficient to get all the generators everytime
+    for (int a = 0; a < Dimension; a++) SU<ncolour>::generator(a, ta[a]);
+
+    for (int a = 0; a < Dimension; a++) {
+    	tmp = 2.0 * adj(Uin) * ta[a] * Uin;
+      for (int b = 0; b < (ncolour * ncolour - 1); b++) {
+        auto Tr = TensorRemove(trace(tmp * ta[b]));
+        pokeColour(U, Tr, a,b);
+      }
+    }  	 
+
+  }
+};
+
+typedef	 AdjointRep<Nc> AdjointRepresentation;
+
+}
+}
+
+
+
+
+#endif