expose gauge group in GImpl and generic Nc fix

Grid/algorithms/iterative/Deflation.h

@@ -54,15 +54,23 @@ class DeflatedGuesser: public LinearFunction<Field> {
 private:
   const std::vector<Field> &evec;
   const std::vector<RealD> &eval;
+  const unsigned int       N;
 
 public:
 
-  DeflatedGuesser(const std::vector<Field> & _evec,const std::vector<RealD> & _eval) : evec(_evec), eval(_eval) {};
+  DeflatedGuesser(const std::vector<Field> & _evec,const std::vector<RealD> & _eval)
+  : DeflatedGuesser(_evec, _eval, _evec.size())
+  {}
+
+  DeflatedGuesser(const std::vector<Field> & _evec, const std::vector<RealD> & _eval, const unsigned int _N)
+  : evec(_evec), eval(_eval), N(_N)
+  {
+    assert(evec.size()==eval.size());
+    assert(N <= evec.size());
+  } 
 
   virtual void operator()(const Field &src,Field &guess) {
     guess = Zero();
-    assert(evec.size()==eval.size());
-    auto N = evec.size();
     for (int i=0;i<N;i++) {
       const Field& tmp = evec[i];
       axpy(guess,TensorRemove(innerProduct(tmp,src)) / eval[i],tmp,guess);

Grid/qcd/action/gauge/GaugeImplTypes.h

@@ -78,6 +78,8 @@ public:
   typedef Lattice<SiteLink>    LinkField; 
   typedef Lattice<SiteField>   Field;
 
+  typedef SU<Nrepresentation> Group;
+
   // Guido: we can probably separate the types from the HMC functions
   // this will create 2 kind of implementations
   // probably confusing the users
@@ -118,7 +120,7 @@ public:
     LinkField Pmu(P.Grid());
     Pmu = Zero();
     for (int mu = 0; mu < Nd; mu++) {
-      SU<Nrepresentation>::GaussianFundamentalLieAlgebraMatrix(pRNG, Pmu);
+      Group::GaussianFundamentalLieAlgebraMatrix(pRNG, Pmu);
       RealD scale = ::sqrt(HMC_MOMENTUM_DENOMINATOR) ;
       Pmu = Pmu*scale;
       PokeIndex<LorentzIndex>(P, Pmu, mu);
@@ -159,15 +161,15 @@ public:
   }
 
   static inline void HotConfiguration(GridParallelRNG &pRNG, Field &U) {
-    SU<Nc>::HotConfiguration(pRNG, U);
+    Group::HotConfiguration(pRNG, U);
   }
 
   static inline void TepidConfiguration(GridParallelRNG &pRNG, Field &U) {
-    SU<Nc>::TepidConfiguration(pRNG, U);
+    Group::TepidConfiguration(pRNG, U);
   }
 
   static inline void ColdConfiguration(GridParallelRNG &pRNG, Field &U) {
-    SU<Nc>::ColdConfiguration(pRNG, U);
+    Group::ColdConfiguration(pRNG, U);
   }
 };