smartbis.f

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c
c ---------------------------------------------------------
c
      subroutine smartbis(badpts,npts,cutoff,numptc,nclust,
     1                    lbase,intcorn,idim,jdim)
c     1                    lbase,intcorn,iscr,jscr,idim,jdim)
c
c  iscr, jscr now stackbased, no need for use of alloc
c
      use amr_module
      implicit double precision (a-h,o-z)

      dimension     badpts(2,npts),intcorn(nsize,maxcl)
c
c  iscr, jscr now stackbased, no need for use of alloc
      dimension     iscr(idim), jscr(jdim)
      integer       nclust, numptc(maxcl)
      parameter(usemin=.4)
c
c :::::::::::::::::::::::::::: SMARTBIS :::::::::::::::::::::::::;
c smart bisect rectangles until cutoff reached for each.
c replaced old bisection routine that cut all grids in half.
c now look for good place to do the cut, based on holes or signatures.
c
c :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::;
c
c     ## initially all points in 1 cluster
      nclust      = 1
      numptc(1)   = npts

      if (gprint) write(outunit,100) nclust
 100  format(' starting smart bisection with ',i5,' clusters')
c
      icl         = 1
      ist         = 1
      iend        = numptc(icl)
c
 10   call moment(intcorn(1,icl),badpts(1,ist),numptc(icl),usenew)
      if (gprint) write(outunit,101) icl,numptc(icl),usenew
 101  format('   testing cluster ',i8,' with ',i9,' pts. use ',e12.4)
c
      if (usenew .lt. cutoff) go to 20
c
c  this cluster ok - on to next
c
      if (.not. gprint) go to 15
         write(outunit,102) icl,numptc(icl),usenew
 102     format('     accepting smart bisected cluster',i4,' with ',i5,
     1          ' pts. use = ',e10.3)
 15   icl   = icl + 1
      if (icl .gt. nclust) go to 200
      ist   = iend + 1
      iend  = ist + numptc(icl) - 1
      go to 10
c
c  smart bisect rectangle (and its cluster) in best location
c
 20   if (nclust .lt. maxcl) go to 25
          write(outunit,900) maxcl
          write(*      ,900) maxcl
 900      format('  too many clusters:  > ',i5)
          stop
 25   continue
c
c smart bisection computes signatures, finds best cut and splits there
c
      call signs(badpts,npts,iscr,jscr,idim,jdim,
     &           ist,iend,ilo,ihi,jlo,jhi)
      call findcut(icl,iscr,jscr,idim,jdim,index,iside,
     &             ilo,ihi,jlo,jhi)
      if (index .eq. 0) then

c         if (usenew .gt. usemin) then
c           icl = icl + 1
c           if (icl .gt. nclust) go to 200
c           ist = iend + 1
c           iend = ist + numptc(icl) - 1
c           go to 10
c         else
c c         bisect in long direction
c           if (ihi-ilo .gt. jhi-jlo) then
c              iside = horizontal
c              index = (ilo + ihi)/2
c           else
c              iside = vertical
c              index = (jlo + jhi)/2
c           endif
c          endif

c 2/28/02 : 3d version uses this branch only;  no 'if' statement.
         icl = icl + 1
         if (icl .gt. nclust) go to 200
         ist = iend + 1
         iend = ist + numptc(icl) - 1
         go to 10
      endif
c
      if (iside .eq. vertical) then
c        fmid = (index-.5)*hy
         fmid = (index-.5)
         idir = 2
      else
         fmid = (index-.5)
         idir = 1
      endif
c
      itop = ist - 1
      ibot = iend + 1
      i    = ist
 50   if (badpts(idir,i) .lt. fmid) go to 60
c
c  point in top half. let it stay, increment counter
c
        itop = itop + 1
        if (itop+1 .ge. ibot) go to 80
             i = i + 1
             go to 50
c
c  point in bottom half. switch with a bottom point that's not yet
c  checked, and increment bot. pointer
c
 60    ibot           = ibot - 1
       temp           = badpts(1,ibot)
       badpts(1,ibot) = badpts(1,i)
       badpts(1,i)    = temp
       temp           = badpts(2,ibot)
       badpts(2,ibot) = badpts(2,i)
       badpts(2,i)    = temp
       if (itop+1 .lt. ibot) go to 50
c
c done smartbisecting icl'th clusters. adjust counts, repeat bisect stage .
c
 80   numptc(icl) = itop - ist + 1
      ibump       = icl + 1
c
c  bump down remaining clusters to make room for the new half of one.
c
      if (ibump .gt. nclust) go to 120
      do 90 ico         = ibump, nclust
      nmove             = nclust - ico + ibump
 90   numptc(nmove + 1) = numptc(nmove)

 120  numptc(ibump)     = iend - ibot + 1
      nclust            = nclust + 1
      iend              = itop
c
c     other half of the cluster has been inserted into cluster list.
c     icl remains the same - need to redo it.
      go to 10
c
c  done: there are nclust clusters.
c
 200  continue
c
      return
      end