====== BFGS ======
it call [[http://users.eecs.northwestern.edu/~nocedal/lbfgsb.html|l-bfgs-b]] routine till:
 - the convergence criteria defined in cg.optional are reached (f(i,j)<fmax for all i,j)
 - the algorithm is not able to find the smaller energy in spite of f>fmax
 - the maximum number of steps exceeds 

===setting of input files:===
==fireball.in:==
   iquench = -5
   nstepf = 1000 ! ! Max number of opt steps, default value = 100
   dt = 0.5 !/only if FIRE minimization is used - last parameter in cgopt.optional >0/

==cgopt.optional:==
This routine uses the same input file as Conjiged Gradients (iquench = -4). It does not use all parameters, but they must be there.
   0.1                  ! NOT USED in BFGS
   0.1                  ! NOT USED in BFGS
   0.00000001           ! NOT USED in BFGS (total energy tolerance )
   0.001                ! fmax - force tolerance - end of minimization if fij<fmax
   10000                ! NOT MORE USED IN BFGS (Max number of opt steps) - now the max. number of steps is given by parameter nstepf in firaball.in
   0                    ! number of restarts in case ftot>fmax (it seems it nave no effect)
   0                    ! if >0 then dt must be defined in fireball.in. Number of FIRE downhill steps after BFGS minimization "fails"

====== FIRE ======
===setting of input files:===
==fireball.in:==
   iquench = -6
   nstepf = 100 ! Max number of opt steps
   dt = 0.5 !timestep in MD

==cgopt.optional:==
This routine uses the same input file as Conjiged Gradients (iquench = -4). It does not use all parameters, but they must be there.
   0.1              ! max displacement 
   0.5              ! NOT USED in FIRE
   0.0              ! total energy tolerance  - the walker can make step uphill if Enew-Emin<Etol, Etol=0 => only downhill steps allowed
   0.001            ! fmax - force tolerance - end of minimization if fij<fmax
   10000            ! NOT MORE USED IN FIRE, Max number of opt steps - NOT MORE USED IN FIRE - see parametr nstepf in fireball.in
   0                ! NOT USED in FIRE minimization