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c
c Flux smoothness based detection
c
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subroutine cles_dcflag(ux,vx,dcflag,ncomps,nvars,
$ ixlo,ixhi, nx, dx, direction,extra)
implicit none
integer ncomps, nvars
integer ixlo, ixhi
integer direction, extra(*)
INTEGER nx
integer dcflag(1:nx+1,1)
double precision ux(ncomps,ixlo:ixhi)
double precision vx(nvars,ixlo:ixhi)
DOUBLE PRECISION dx
integer i, m, slow, shigh, loop, size, enoOrder
double precision smoothness, dmdx, maxv(4), minv(4), variance(4)
integer span
double precision TriggerValue, smooth_eps
TriggerValue = 0.0d0
smooth_eps = 0.001
span = 3
enoOrder = extra(1)
size = enoOrder-1
! ---- test criteria at each point
DO i = 1, nx+1, 1
DO loop =1,4
do m=i-size, i+size-1
dmdx = abs(fx(loop,m+1)-fx(loop,m-1))
if ( m .eq. i-size ) then
maxv(loop) = dmdx
minv(loop) = dmdx
else
maxv(loop) = MAX(maxv(loop), dmdx)
minv(loop) = MIN(minv(loop), dmdx)
endif
enddo
variance(loop) = maxv(loop)/(minv(loop)+smooth_eps)
if ( loop .eq. 1 ) then
smoothness = variance(loop)
else
smoothness = MAX(smoothness, variance(loop))
endif
END DO
IF ( smoothness .gt. TriggerValue ) THEN
! we are at a shock
! ---- we will use WENO here
slow = max(i-span,1)
shigh = min(i+span,nx+1)
do m=slow,shigh
dcflag(m,direction) = 1
enddo
END IF
END DO
return
end