In which parts of the resource codes of LAMMPS the order of pair_style coefficients at input file are set?

I want to know that in which parts of the resource codes of LAMMPS the order of pair coefficients at input file are determined?
For example in pair_coeff 2 3 2.0 1.0 1.12 defines the coefficients for LJ , I want to know where the order of these coefficient are set. As an example change the mentioned order to: pair_coeff 2 3 1.0 1.0 2.0 12.

The parsing of pair_coeff commands happens in the individual coeff() function of each pair style. 3.5. Pair styles — LAMMPS documentation

Thanks, as an example of Gay-Berne pair_style which part of this function?
void PairGayBerne::coeff(int narg, char **arg)
if (narg < 10 || narg > 11)
error->all(FLERR,“Incorrect args for pair coefficients”);
if (!allocated) allocate();

int ilo,ihi,jlo,jhi;

double epsilon_one = utils::numeric(FLERR,arg[2],false,lmp);
double sigma_one = utils::numeric(FLERR,arg[3],false,lmp);
double eia_one = utils::numeric(FLERR,arg[4],false,lmp);
double eib_one = utils::numeric(FLERR,arg[5],false,lmp);
double eic_one = utils::numeric(FLERR,arg[6],false,lmp);
double eja_one = utils::numeric(FLERR,arg[7],false,lmp);
double ejb_one = utils::numeric(FLERR,arg[8],false,lmp);
double ejc_one = utils::numeric(FLERR,arg[9],false,lmp);

double cut_one = cut_global;
if (narg == 11) cut_one = utils::numeric(FLERR,arg[10],false,lmp);

int count = 0;
for (int i = ilo; i <= ihi; i++) {
for (int j = MAX(jlo,i); j <= jhi; j++) {
epsilon[i][j] = epsilon_one;
sigma[i][j] = sigma_one;
cut[i][j] = cut_one;
if (eia_one != 0.0 || eib_one != 0.0 || eic_one != 0.0) {
well[i][0] = pow(eia_one,-1.0/mu);
well[i][1] = pow(eib_one,-1.0/mu);
well[i][2] = pow(eic_one,-1.0/mu);
if (eia_one == eib_one && eib_one == eic_one) setwell[i] = 2;
else setwell[i] = 1;
if (eja_one != 0.0 || ejb_one != 0.0 || ejc_one != 0.0) {
well[j][0] = pow(eja_one,-1.0/mu);
well[j][1] = pow(ejb_one,-1.0/mu);
well[j][2] = pow(ejc_one,-1.0/mu);
if (eja_one == ejb_one && ejb_one == ejc_one) setwell[j] = 2;
else setwell[j] = 1;
setflag[i][j] = 1;

if (count == 0) error->all(FLERR,“Incorrect args for pair coefficients”);

In this part, obviously.

What about the coefficients appeared in front of the pair style? e.g. pair_style gayberne 1.0 1.0 1.0 10.0

How about reading the documentation?

I found them in setting method of pair_style PairGayBerne. e.g.

gamma = utils::numeric(FLERR,arg[0],false,lmp);
upsilon = utils::numeric(FLERR,arg[1],false,lmp)/2.0;
mu = utils::numeric(FLERR,arg[2],false,lmp);
cut_global = utils::numeric(FLERR,arg[3],false,lmp);

Excuse if sometimes my question is so elementary. I am a beginner! :neutral_face:

Sorry, but that is not a valid excuse for not doing your due diligence and study the available information in the LAMMPS manual before asking questions. I even have pointed it out to you. So even if the very first post can be excused by being a beginner and not having memorized the entire 2500+ pages of the LAMMPS manual, after being pointed to it, you should be able to figure out the rather trivial issues in the remaining questions on your own or have to ask more specific questions that are not fully addressed in the documentation pages.

I am very much trying to be accommodating and know that things can be difficult for somebody with limited inexperience, but similarly it is the responsibility of that inexperienced person to act responsible and not exploit that. Remember that people responding here volunteer their time.