src1.f.html clawcode2html   
 Source file:   src1.f
 Directory:   /Users/rjl/rjlsvn/papers/pathconwb10/code
 Converted:   Fri Jan 8 2010 at 15:48:01
 This documentation file will not reflect any later changes in the source file.

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c
c
c =========================================================
      subroutine src1(maxmx,meqn,mbc,mx,xlower,dx,q,maux,aux,t,dt)
c =========================================================

c     # Source term is incorporated in fwave in rp1 if mthsrc > 1.

      implicit double precision (a-h,o-z)
      dimension q(1-mbc:maxmx+mbc, meqn)
      dimension aux(1-mbc:maxmx+mbc, 1)
c
      common /comrp/ u
      common /comsrc/ mthsrc

      if (mthsrc.eq.1) then
         
Fractional step for source term: Solve $q_t = -q \sigma'(x)$ over timestep of length dt. Approximate $\sigma'(x)$ using centered difference and then solve exactly.
 
          do i=1,mx
             x = xlower + (i-0.5d0)*dx
             sigp = (aux(i+1,1) - aux(i-1,1)) / (2.d0*dx)
             q(i,1) = q(i,1) * dexp(-sigp*dt)
             enddo
c     # else do nothing in this routine: source term in Riemann solver.
      endif
c
      return
      end