source: EXAMPLES/multicanonical.f

!**************************************************************     
! Calculate weights for a multicanonical simulation
!
!
! Copyright 2003-2005  Frank Eisenmenger, U.H.E. Hansmann,
!                      Shura Hayryan, Chin-Ku Hu
! Copyright 2007       Frank Eisenmenger, U.H.E. Hansmann,
!                      Jan H. Meinke, Sandipan Mohanty
!
! **************************************************************


      program multicanonical_main
      
      use multicanonical

      include "../INCL.H"

      
!! Storage space for force-field library paths, seuence-file name, and variable-file name
      character*80 libdir, seqfile, varfile
!! Storage space for end groups
      character grpn*4,grpc*4
      integer nsweeps, nup, kmin, kmax
      double precision temp, binWidth
      logical l_iter
      
! =================================================== Energy setup

!     Directory for SMMP libraries
!     Change the following directory path to where you want to put SMMP
!     libraries of residues. 
      libdir='../../SMMP/'

!!     Choose energy type with the following switch
!        0  => ECEPP2 or ECEPP3 depending on the value of sh2
!        1  => FLEX 
!        2  => Lund force field
!        3  => ECEPP with Abagyan corrections
!
      ientyp = 0

      sh2=.false.         ! .true. for ECEPP/2; .false. for ECEPP3
      epsd=.false.        ! .true. for  distance-dependent  dielectric
                          !  permittivity

      itysol= 0    !  0: vacuum
                   ! >0: numerical solvent energy
                   ! <0: analytical solvent energy & gradients

      call init_energy(libdir)

! ================================================= Structure setup

      grpn = 'nh2' ! N-terminal group
      grpc = 'cooh'! C-terminal group

      iabin = 1  ! =0: read from PDB-file
                 ! =1: ab Initio from sequence (& variables)
      seqfile='1vp.seq'
!      varfile='EXAMPLES/enkefa.var'
      varfile = ' '
      ntlml = 0
      
      call init_molecule(iabin,grpn,grpc,seqfile,varfile)

      seed = 52428
      call sgrnd(seed)
      upchswitch= 0 !Turn off biased Gaussian step

      nsweeps = 100000
      nup = 5000
      kmin = -12
      kmax = 20
      binWidth = 1.0
      l_iter = .false.
      temp=1000.0

!      call mulcan_par(nsweeps, nup, temp, kmin, kmax, binWidth, l_iter)
! Uncomment the following three lines to perform a multi canonical simulation with
! the parameters stored in muca.d
       nmes = 1000
       call mulcan_sim(nmes, nsweeps, nmes, nup, kmin, kmax, binWidth, 
     &                l_iter)
      end program multicanonical_main