// weight parameters (indices: nb of hidden layers, layer)
// weights for one hidden layer
double*wgt11;// row is hidden id, column is input id
double*wgt12;
// weights for two hidden layers
double*wgt21;
double*wgt22;
double*wgt23;
// size values
intnl;//number of layers
intnsp;// number of species
std::vector<int>nhl;// number of nodes per hidden layer
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
int*iaddr2;// for 2-body potential
int*iaddr3;// for 3-body potential
// parameters of the symmetry functions
// eta = cnst(1, isf) // isf is symmetry function id
// alpha = cnst(2, isf)
double*cnst;
// cutoff radii for 2 and 3 body potentials
doublercin,rc3;
// nb of parameters per symmetry function type
intncnst_type[200];
// n in n-body potential per symmetry function type