double precision function funmin ( xmer, nmer )
	implicit none
	integer nmer
	double precision xmer(nmer)

      include 'sizes.i'
      include 'files.i'
      include 'inform.i'
      include 'iounit.i'
      include 'math.i'
      include 'omega.i'
      include 'zcoord.i'
      include 'usage.i'
	include 'atoms.i'

	integer mnat, i, ixyz, nunit
	double precision energy, fl

	integer ifirst
	save ifirst
	data ifirst / 0 /

	if (ifirst.eq.0) then
		ifirst = 1
		call initial
		call getint
		call mechanic
		nomega = 0
		mnat = n
		do i=4,mnat
			if (iz(4,i).eq.0) then
				nomega = nomega+1
				iomega(1,nomega) = iz(1,i)
				iomega(2,nomega) = iz(2,i)
				dihed(nomega) = ztors(i)/radian
				zline(nomega) = i
			end if
		end do
		do i=1,mnat
			use(i) = .true.
		end do
		if (nomega.ne.nmer) stop 'NMER NOMEGA'
		do i = 1, nomega
			call setx1(i,ztors(zline(i)))
		end do
	end if

	do i = 1, nomega
		ztors(zline(i)) = xmer(i)
	end do

	call makexyz
	funmin = energy()

	call getfla(1,fl)
	if (fl.ne.0.) then
		fl = 0.
		call setfla(1,fl)
		ixyz = nunit()
		if (ixyz.eq.-1) stop 'ERR: NO FREE UNIT'
		call prtxyz(ixyz)
	end if

	end

	subroutine granal ( nmer, xmer, gmer )
	implicit none
	integer nmer
	double precision xmer(nmer), gmer(nmer)

      include 'sizes.i'
      include 'omega.i'
      include 'zcoord.i'
	include 'atoms.i'

	integer i
	double precision energy, radian

	do i=1,nomega
		ztors(zline(i)) = xmer(i)
	end do

	call makexyz
	call gradrot(energy,gmer)

	radian = 57.29577951308232088d0
	do i=1,nomega
		gmer(i) = gmer(i)/radian
	end do

	end