rp1.f.html
Source file:   rp1.f
Directory:   /home/rjl/git/rjleveque/clawpack-4.x/book/chap6/compareadv
Converted:   Tue Jul 26 2011 at 12:59:02   using clawcode2html
This documentation file will not reflect any later changes in the source file.

 
c
c
c =========================================================
      subroutine rp1(maxmx,meqn,mwaves,mbc,mx,ql,qr,auxl,auxr,
     &		 wave,s,amdq,apdq)
c =========================================================
c
c     # solve Riemann problems for the 1D advection equation q_t + u*q_x = 0.
c     # For constant advection velocity u, passed in common block.
c
c     # The advection speed u is passed in the common block comrp
c     # On input, ql contains the state vector at the left edge of each cell
c     #           qr contains the state vector at the right edge of each cell
c     # On output, wave contains the waves,
c     #            s the speeds,
c     #            amdq the  left-going flux difference  A^- \Delta q
c     #            apdq the right-going flux difference  A^+ \Delta q
c
c     # Note that the i'th Riemann problem has left state qr(i-1,:)
c     #                                    and right state ql(i,:)
c     # From the basic clawpack routine step1, rp is called with ql = qr = q.
c
c
      implicit double precision (a-h,o-z)
      dimension   ql(1-mbc:maxmx+mbc, meqn)
      dimension   qr(1-mbc:maxmx+mbc, meqn)
      dimension    s(1-mbc:maxmx+mbc, mwaves)
      dimension wave(1-mbc:maxmx+mbc, meqn, mwaves)
      dimension amdq(1-mbc:maxmx+mbc, meqn)
      dimension apdq(1-mbc:maxmx+mbc, meqn)
      common /comrp/ u
c
c
c
      do 30 i=2-mbc,mx+mbc
c
c        # Compute the wave and speed
c
         wave(i,1,1) = ql(i,1) - qr(i-1,1)
         s(i,1) = u
c
c
c        # Compute the wave and speed
c
         wave(i,1,1) = ql(i,1) - qr(i-1,1)
         s(i,1) = u
         amdq(i,1) = dmin1(u, 0.d0) * wave(i,1,1)
         apdq(i,1) = dmax1(u, 0.d0) * wave(i,1,1)
   30    continue
c
      return
      end