Topmost level solver computations are concentrated in s__solve.cc file in

 SIM::solve(...) 

inside it main important steps:

 do { 

assume we have some value of unknowns: X_c calculate model parameters

   evaluate models; 

load matrices (Jacobian J and vector FG)

note, that dumping is implemented duing matrix & vector loading process.

   load_marix(); 

solve equations and obtan new poin X_n

   solve_equations(); 

until equations will converge or iteration limit will not be acieved

  } while ( ! converged && ! _sim-> exceeds_iteration_limit(it1));