// weight parameters (indices: nb of hidden layers, layer)
// weights for one hidden layer
std::vector<double> wgt11; // row is hidden id, column is input id
std::vector<double> wgt12;
// weights for two hidden layers
std::vector<double> wgt21;
std::vector<double> wgt22;
std::vector<double> wgt23;
// size values
int nl; //number of layers
int nsp; // number of species
std::vector<int> nhl; // number of nodes per hidden layer
std::vector<int> itype; // array of symmetry function ids
// contains beginnings and ends of symmetry function id to consider for each species pair: iaddr2(i, j, k) i: 1 for start, 2 for end; j, k pair of species
std::vector<int> iaddr2; // for 2-body potential
std::vector<int> iaddr3; // for 3-body potential
// parameters of the symmetry functions
// eta = cnst(1, isf) // isf is symmetry function id
// alpha = cnst(2, isf)
std::vector<double> cnst;
// cutoff radii for 2 and 3 body potentials
double rcin, rc3;
// nb of parameters per symmetry function type
int ncnst_type[200];
// n in n-body potential per symmetry function type