c-----------------------------------------------------------------------
c Two-dimensional restriction operator for AMROC.
c A coarse cell value is overwritten by the mean value
c of all refined cells within this particular coarse cell.
c
c Interface:
c mfx,mfy := shape of fine grid
c mcx,mcy := shape of coarse grid
c
c uf(,) := fine grid
c uc(,) := coarse grid
c
c lbc(2) := lower bound for coarse grid
c ubc(2) := upper bound for coarse grid
c lbf(2) := lower bound for fine grid
c ubf(2) := upper bound for fine grid
c lbr(2) := lower bound for region restriction desired
c ufr(2) := upper bound for region restriction desired
c shaper(2) := shape of region restriction desired
c
c Copyright (C) 2002 Ralf Deiterding
c Brandenburgische Universitaet Cottbus
c
c Copyright (C) 2003-2007 California Institute of Technology
c Ralf Deiterding, ralf@cacr.caltech.edu
c-----------------------------------------------------------------------
subroutine restrict2(uf,mfx,mfy,lbf,ubf,
& uc,mcx,mcy,lbc,ubc,
& lbr,ubr,shaper,meqn,mbc)
implicit none
integer meqn, mbc, mcx, mcy, mfx, mfy, shaper(2)
double precision uf(meqn,mfx,mfy), uc(meqn,mcx,mcy)
integer lbf(2), ubf(2),
& lbc(2), ubc(2),
& lbr(2), ubr(2)
c Local variables
integer i, j, ii, jj, imin, imax, jmin, jmax, m,
& ifine, icoarse, jfine, jcoarse,
& refine, stridec, stridef, getindx
integer mbcf
c- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
c See definition of member-function extents() in BBox.h
c for calculation of stride
c- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
stridec = (ubc(1) - lbc(1))/(mcx-1)
stridef = (ubf(1) - lbf(1))/(mfx-1)
refine = stridec/stridef
mbcf = mbc * stridef
c- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
c Find coarse domain over which to refine
c Take three regions and select out intersection
c- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
imin = max(lbf(1)+mbcf, lbc(1), lbr(1))
imax = min(ubf(1)-mbcf, ubc(1), ubr(1))
jmin = max(lbf(2)+mbcf, lbc(2), lbr(2))
jmax = min(ubf(2)-mbcf, ubc(2), ubr(2))
if (mod(imin-lbc(1),stridec) .ne. 0) then
imin = imin + stridec - mod(imin-lbc(1),stridec)
endif
if (mod(jmin-lbc(2),stridec) .ne. 0) then
jmin = jmin + stridec - mod(jmin-lbc(2),stridec)
endif
c Inject points to coarse grid from fine grid
c Loop from lower bound to upper bound with stride of refine.
c Convert the integer coordinates to fine and coarse grid absolute
c coordinates...
do 10 j = jmin, jmax, stridec
jfine = getindx(j, lbf(2), stridef)
jcoarse = getindx(j, lbc(2), stridec)
do 10 i = imin, imax, stridec
ifine = getindx(i, lbf(1), stridef)
icoarse = getindx(i, lbc(1), stridec)
! if(icoarse .gt. mcx .or. jcoarse .gt. mcy)then
! write(0,*)'ERROR in restriction: ',icoarse,jcoarse
! end if
do 10 m=1, meqn
uc(m,icoarse,jcoarse) = 0
do 20 ii = 0, refine-1
do 20 jj = 0, refine-1
uc(m,icoarse,jcoarse) = uc(m,icoarse,jcoarse) +
& uf(m,ifine+ii,jfine+jj)
20 continue
uc(m,icoarse,jcoarse) = uc(m,icoarse,jcoarse) / refine**2
10 continue
return
end