*******************************************************************************

	program MC_to_MD

*******************************************************************************
c
c       This program is designed to convert a data file to BIOSYM format
c       The input file for the nvt Monte Carlo simulation can be read in
c       and then converted to a car file
c

c	To compile non-graphics programs use : 
c        f77 $(OPT) MC_to_MD.f -o MC_to_MD 

        parameter (n = 1000)
        real rx(n), ry(n), rz(n)
        real length, density, sigma, angle 
        character*40	fname
        character*40	gname
	integer	        natom
c
c 
	 print *,'Enter MC filename (inside single quotes) : '
	 read(5,*) fname
c
         call readcn( fname, rx, ry, rz, natom )
c
         print *,'This cell is in reduced Lennard-Jones units'
         print *,'The cell is of unit length'
         print *,'To convert to Angstroms you must input the density'
         print *,'and the value of the L-J sigma parameter'
         print *,'Input sigma:'
         read(5,*) sigma
         print *,'Input box length in reduced units:'
         read(5,*) length 
         length=length*sigma
c
         print *,'Enter MD filename (inside single quotes): '
         read(5,*) gname
c
         open(unit=7,file=gname,form='formatted',
     $                            status='new',err=990)
c
         angle = 90.0000
         write(7,'(a17)') '!BIOSYM archive 3'
         write(7,'(a6)') 'PBC=ON'
         write(7,'(a20)') '       '
         write(7,'(a29)') '!DATE Mon Dec 19 3:10:05 2000'
         write(7,210) length, length, length, angle, angle, angle

         do 200 i=1,natom
          rx(i) = rx(i)*sigma
          ry(i) = ry(i)*sigma
          rz(i) = rz(i)*sigma
         write(7,220) i,rx(i), ry(i), rz(i),i
200      continue
210      format('PBC  ',5(f9.6,1x),f9.6,'(P1)')
220      format('AR',i3,3(2x,f13.9),1x,'ARH  ',i3,
     $ '    ar      Ar  0.000')
         write(7,170) 'end'
         write(7,170) 'end'
170      format(a3)
         goto 999
990      continue
         print *,'Error in output file'
999      continue
c
         end

        SUBROUTINE READCN ( CNFILE, RX, RY, RZ, NN )


C    *******************************************************************
C    ** SUBROUTINE TO READ IN INITIAL CONFIGURATION FROM UNIT 10      **
C    *******************************************************************

        INTEGER     N,I
        PARAMETER ( N = 1000 )
        CHARACTER   CNFILE*(*)
        CHARACTER*80 RECORD
        REAL        RX(N), RY(N), RZ(N)
        INTEGER     CNUNIT, NN
        PARAMETER ( CNUNIT = 10 )

C     ******************************************************************
        
        OPEN ( UNIT = CNUNIT, FILE = CNFILE, STATUS = 'OLD',
     :         FORM = 'FORMATTED' )

        READ( CNUNIT,'(A80)',END=3000,ERR=3000) RECORD 
        print *, record
        READ(RECORD,130,ERR=3000) NN
        print *,nn
C        IF ( NN .NE. N ) STOP ' INCORRECT NUMBER OF ATOMS '
        READ( CNUNIT,'(A80)',END=3000,ERR=3000) RECORD 
        READ( CNUNIT,'(A80)',END=3000,ERR=3000) RECORD 
        READ( CNUNIT,'(A80)',END=3000,ERR=3000) RECORD 
        DO 2000 I=1,NN
          READ( CNUNIT,'(A80)',END=3000,ERR=3000) RECORD 
          READ(RECORD,120,ERR=3000) RX(I), RY(I), RZ(I) 
2000    CONTINUE
120     FORMAT(3(F12.6),A44)
130     FORMAT(1X,I4,A75)

        CLOSE ( UNIT = CNUNIT )
        GOTO 3001
3000    CONTINUE
        PRINT *,'ERROR IN READCN'
3001    CONTINUE
        RETURN
        END