*     ------------------------------------------------------------------
*     File snmain.f  (Unix version)
*     This is a main program to illustrate the use of subroutine SNOPT,
*     which is part of the SNOPT package.
*
*     31 Jul 1996: First   version.
*     12 Feb 1998: Current version.
*     ------------------------------------------------------------------
      program            snmain
      implicit           double precision (a-h,o-z)

      parameter        ( maxm   = 1000,
     &                   maxn   = 1000,
     &                   maxne  = 3000,
     &                   nName  = 1 )

      character*8        Prob, Names(nName)
      integer            ha(maxne) , hs(maxn+maxm)
      integer            ka(maxn+1)
      double precision   a(maxne)  , bl(maxn+maxm), bu(maxn+maxm),
     &                   x(maxn+maxm), pi(maxm)   , rc(maxn+maxm)

*     SNOPT workspace

      parameter          (  lenrw = 20000)
      double precision   rw(lenrw)
      parameter          (  leniw = 10000) 
      integer            iw(leniw)
      parameter          (  lencw =   500) 
      character*8        cw(lencw)

      logical            byname
      character*20       lfile
      external           HexCon, HexObj

*     ------------------------------------------------------------------
*     Specify some of the SNOPT files.
*     iSpecs  is the Specs file   (0 if none).
*     iPrint  is the Print file   (0 if none).
*     iSumm   is the Summary file (0 if none).
*
*     nout    is an output file used here by snmain.

      iSpecs = 4
      iPrint = 15
      iSumm  = 6
      nout   = 6

      byname = .true.
 
      if ( byname ) then

*        Unix and DOS systems.  Open the Specs and print files.

         lfile = 'snmain.spc'
         open( iSpecs, file=lfile, status='OLD',     err=800 )

         lfile = 'snmain.out'
         open( iPrint, file=lfile, status='UNKNOWN', err=800 )
      end if

*     ------------------------------------------------------------------
*     First,  snInit MUST be called to initialize optional parameters 
*     to their default values.
*     ------------------------------------------------------------------
      call snInit( iPrint, iSumm,
     &             cw, lencw, iw, leniw, rw, lenrw )

*     ------------------------------------------------------------------
*     Read a Specs file (Optional).
*     ------------------------------------------------------------------
      call snSpec( iSpecs, inform,
     &             cw, lencw, iw, leniw, rw, lenrw )

      if (inform .ge. 2) then
         write(nout, *) 'iSpecs > 0 but no Specs file found'
         go to 990
      end if

*     Set up the data structure for the sparse Jacobian.
*     Assign dummy values for the nonlinear elements. 

      call HexDat( Prob, maxm, maxn, maxne, inform,
     &             m, n, ne, nnCon, nnObj, nnJac, iObj, ObjAdd,
     &             a, ha, ka, bl, bu, hs, x, pi )

*     ------------------------------------------------------------------
*     Specify any options not set in the Specs file.
*     i1 and i2 may refer to the Print and Summary file respectively.
*     Setting them to 0 suppresses printing.
*     ------------------------------------------------------------------
      itnlim = 250
      i1     =   0
      i2     =   0
      call snseti( 'Iterations        ', itnlim, i1, i2, inform,
     &             cw, lencw, iw, leniw, rw, lenrw )

*     ------------------------------------------------------------------
*     Go for it, using a Cold start.
*     hs     need not be set if a basis file is to be input.
*            Otherwise, each hs(1:n) should be 0, 1, 2, 3, 4, or 5.
*            The values are used by the Crash procedure m2crsh
*            to choose an initial basis B.
*            If hs(j) = 0 or 1, column j is eligible for B.
*            If hs(j) = 2, column j is initially superbasic (not in B).
*            If hs(j) = 3, column j is eligible for B and is given
*                          preference over columns with hs(j) = 0 or 1.
*            If hs(j) = 4 or 5, column j is initially nonbasic.
*     ------------------------------------------------------------------
      call snopt ( 'Cold', m, n, ne, nName,
     &             nnCon, nnObj, nnJac,
     &             iObj, ObjAdd, Prob,
     &             HexCon, HexObj,
     &             a, ha, ka, bl, bu, Names,
     &             hs, x, pi, rc, 
     &             inform, mincw, miniw, minrw,
     &             nS, nInf, sInf, Obj,
     &             cw, lencw, iw, leniw, rw, lenrw,
     &             cw, lencw, iw, leniw, rw, lenrw )

      if (inform .eq. 42 .or. inform .eq. 43 .or. inform .eq. 44) then
         write(nout, *) ' '
         write(nout, *) 'Estimate of required lencw:', mincw
         write(nout, *) 'Estimate of required leniw:', miniw
         write(nout, *) 'Estimate of required lenrw:', minrw
         go to 910
      end if

      write(nout, *) ' '
      write(nout, *) 'snopt finished.'
      write(nout, *) 'inform =', inform
      write(nout, *) 'nInf   =', nInf
      write(nout, *) 'sInf   =', sInf
      write(nout, *) 'Obj    =', Obj
      if (inform .ge. 20) go to 910
      stop

*     ------------------------------------------------------------------
*     Error exit.
*     ------------------------------------------------------------------
  800 write(nout, 4000) 'Error while opening file', lfile
      stop

  910 write(nout, *) ' '
      write(nout, *) 'STOPPING because of error condition'

  990 stop

 4000 format(/  a, 2x, a  )

*     end of main program to test subroutine snopt
      end