c
c =====================================================
double precision function philim(a,b,meth)
c =====================================================
implicit double precision(a-h,o-z)
c
c # Compute a limiter based on wave strengths a and b.
c # meth determines what limiter is used.
c # a is assumed to be nonzero.
c
r = b/a
go to (10,20,30,40,50) meth
c
10 continue
c --------
c # minmod
c --------
philim = dmax1(0.d0, dmin1(1.d0, r))
return
c
20 continue
c ----------
c # superbee
c ----------
philim = dmax1(0.d0, dmin1(1.d0, 2.d0*r), dmin1(2.d0, r))
return
c
30 continue
c ----------
c # van Leer
c ----------
philim = (r + dabs(r)) / (1.d0 + dabs(r))
return
c
40 continue
c ------------------------------
c # monotinized centered
c ------------------------------
c = (1.d0 + r)/2.d0
philim = dmax1(0.d0, dmin1(c, 2.d0, 2.d0*r))
return
c
50 continue
c ------------------------------
c # van Albada
c ------------------------------
philim = 1.d0
if (dabs(r).lt.1d36)
& philim = dmax1(0.d0, r*(1.d0+r)/(1.d0+r**2))
return
c
end