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