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errest.f.html |
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Source file: errest.f
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Directory: /home/rjl/git/rjleveque/clawpack-4.x/amrclaw/2d/lib
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Converted: Sun May 15 2011 at 19:16:13
using clawcode2html
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This documentation file will
not reflect any later changes in the source file.
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c
c -------------------------------------------------------------
c
subroutine errest (nvar,naux,lcheck)
c
implicit double precision (a-h,o-z)
include "call.i"
c
c # no sense computing new time step if just for error estimation,
c # vtime removed from arg list to stepgrid, but new dt not used
c :::::::::::::::::::::::::: ERREST :::::::::::::::::::::::::::::::::::
c for all grids at level lcheck:
c estimate the error by taking a large (2h,2k) step based on the
c values in the old storage loc., then take one regular (and for
c now wasted) step based on the new info. compare using an
c error relation for a pth order accurate integration formula.
c flag error plane as either bad (needs refinement), or good.
c
c call the regular integrator on a grid twice as coarse.
c initialize such a grid directly, instead of trick dimensioning.
c this is to make other l1 type estimates easier to program.
c :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
c
hx = hxposs(lcheck)
hy = hyposs(lcheck)
hx2 = 2.d0*hx
hy2 = 2.d0*hy
mptr = lstart(lcheck)
5 continue
nx = node(ndihi,mptr) - node(ndilo,mptr) + 1
ny = node(ndjhi,mptr) - node(ndjlo,mptr) + 1
mitot = nx + 2*nghost
mjtot = ny + 2*nghost
locnew = node(store1,mptr)
locold = node(store2,mptr)
locaux = node(storeaux,mptr)
mi2tot = nx/2 + 2*nghost
mj2tot = ny/2 + 2*nghost
time = rnode(timemult,mptr)
dt = possk(lcheck)
tpre = time - dt
c
c prepare double the stencil size worth of boundary values,
c then coarsen them for the giant step integration.
c
midub = nx+4*nghost
mjdub = ny+4*nghost
locdub = igetsp(midub*mjdub*(nvar+naux))
locbgc = igetsp(mi2tot*mj2tot*(nvar+naux))
node(errptr,mptr) = locbgc
ng2 = 2*nghost
c # transfer soln. into grid with twice the ghost cells
call copysol(alloc(locdub),alloc(locold),nvar,mitot,mjtot,
1 nghost,midub,mjdub,ng2)
c
if (naux .gt. 0) then
locaxb = locdub + midub*mjdub*nvar
locaxc = locbgc + mi2tot*mj2tot*nvar
xl = rnode(cornxlo, mptr)
yb = rnode(cornylo, mptr)
maxmx = midub - 4*nghost
mx = maxmx
maxmy = mjdub - 4*nghost
my = maxmy
call setaux(maxmx,maxmy,2*nghost,mx,my,xl,yb,hx,hy,
& naux,alloc(locaxb))
call auxcoarsen(alloc(locaxb),midub,mjdub,
1 alloc(locaxc),mi2tot,mj2tot,naux,auxtype)
else
locaxb = 1
endif
c # fill it - use enlarged (before coarsening) aux arrays
call bound(tpre,nvar,ng2,alloc(locdub),midub,mjdub,mptr,
1 alloc(locaxb),naux)
c coarsen by 2 in every direction
call coarsen(alloc(locdub),midub,mjdub,
1 alloc(locbgc),mi2tot,mj2tot,nvar)
call reclam(locdub,midub*mjdub*(nvar+naux))
c
c
c************************************************************************
c changed. now locbig filled from spest, always, even if no
c user estimation routine. reclaim space later tho.
c We now fill bndry values at time t = time, in preparation
c for calculating the solution on the grid mptr for error estimation.
c
c locbig = igetsp(mitot*mjtot*nvar)
c node(tempptr,mptr) = locbig
c # straight copy into scratch array so don't mess up latest soln.
c do 10 i = 1, mitot*mjtot*nvar
c 10 alloc(locbig+i-1) = alloc(locnew+i-1)
c
c call bound(time,nvar,nghost,alloc(locbig),mitot,mjtot,mptr,
c 1 alloc(locaux),naux)
c************************************************************************
c
mptr = node(levelptr,mptr)
if (mptr .ne. 0) go to 5
c
hx = hxposs(lcheck)
hy = hyposs(lcheck)
hx2 = 2.d0*hx
hy2 = 2.d0*hy
dt = possk(lcheck)
dt2 = 2. * dt
mptr = lstart(lcheck)
25 continue
nx = node(ndihi,mptr) - node(ndilo,mptr) + 1
ny = node(ndjhi,mptr) - node(ndjlo,mptr) + 1
mitot = nx+ 2*nghost
mjtot = ny+ 2*nghost
mi2tot = nx/2 + 2*nghost
mj2tot = ny/2 + 2*nghost
c
c # this scratch storage will be used both for regular and half
c # sized grid. different dimensions in stepgrid - do not reuse.
locfp = igetsp(mitot*mjtot*nvar)
locfm = igetsp(mitot*mjtot*nvar)
locgp = igetsp(mitot*mjtot*nvar)
locgm = igetsp(mitot*mjtot*nvar)
locaux = node(storeaux,mptr)
c
locbgc = node(errptr,mptr)
c
locaxc = locbgc+nvar*mi2tot*mj2tot
c should we set to 1 if naux=0?
c
evol = evol + (nx/2)*(ny/2)
xlow = rnode(cornxlo,mptr) - nghost*hx2
ylow = rnode(cornylo,mptr) - nghost*hy2
call stepgrid(alloc(locbgc),alloc(locfm),alloc(locfp),
1 alloc(locgm),alloc(locgp),
2 mi2tot,mj2tot,nghost,
3 dt2,dtnew2,hx2,hy2,nvar,
4 xlow,ylow,tpre,mptr,naux,alloc(locaxc))
c
c the one giant step based on old values is done. now take
c one regular step based on new values.
c
evol = evol + nx * ny
xlow = rnode(cornxlo,mptr) - nghost*hx
ylow = rnode(cornylo,mptr) - nghost*hy
locbig = node(tempptr,mptr)
loctmp = node(store2,mptr)
c
c **********************************************************************
c ****** changed. spatial error now done from separate routine spest ******
c
c estimate spatial component of error - use old values before
c integration to get accurate boundary gradients
c
c locerrsp = igetsp(mitot*mjtot)
c call errsp(alloc(locbig), alloc(locerrsp), mitot,mjtot,
c & nvar, mptr,nghost, eprint, outunit)
c **********************************************************************
call stepgrid(alloc(locbig),alloc(locfm),alloc(locfp),
1 alloc(locgm),alloc(locgp),
2 mitot,mjtot,nghost,
3 dt,dtnew,hx,hy,nvar,
4 xlow,ylow,time,mptr,naux,alloc(locaux))
c
call reclam(locfp, mitot*mjtot*nvar)
call reclam(locfm, mitot*mjtot*nvar)
call reclam(locgp, mitot*mjtot*nvar)
call reclam(locgm, mitot*mjtot*nvar)
c
call errf1(alloc(locbig),nvar,
1 alloc(locbgc),mptr,mi2tot,mj2tot,
2 mitot,mjtot,alloc(loctmp))
call reclam(locbgc,mi2tot*mj2tot*(nvar+naux))
c reclaiming locbig is now done from bufnst, since this routine
c will not be called if tol<0
c call reclam(locbig,mitot*mjtot*nvar)
c
mptr = node(levelptr, mptr)
if (mptr .ne. 0) go to 25
c
return
end