rp1.f.html | clawcode2html |
Source file: rp1.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. |
c c c ========================================================= subroutine rp1(maxmx,meqn,mwaves,mbc,mx,ql,qr,auxl,auxr, & fwave,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, fwave contains the f-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 auxl(1-mbc:maxmx+mbc, 1) dimension auxr(1-mbc:maxmx+mbc, 1) dimension s(1-mbc:maxmx+mbc, mwaves) dimension fwave(1-mbc:maxmx+mbc, meqn, mwaves) dimension amdq(1-mbc:maxmx+mbc, meqn) dimension apdq(1-mbc:maxmx+mbc, meqn) common /comrp/ u common /comsrc/ mthsrc c c c do 30 i=2-mbc,mx+mbc c c # Compute the wave and speed c Qim = qr(i-1,1) Qi = ql(i,1) sigim = auxr(i-1,1) sigi = auxl(i,1) if (mthsrc.eq.1) then c # fractional step, source term done in src1 fwave(i,1,1) = u*(Qi - Qim) else if (mthsrc.eq.2) then c # f-wave includes arithmetic average src = -0.5d0*(Qi+Qim) * (sigi-sigim) fwave(i,1,1) = u*(Qi - Qim) - src else if (mthsrc.eq.3) then c # f-wave using path integrals Qihat = Qim*dexp(-(sigi-sigim)/u) Qimhat = Qi*dexp(+(sigi-sigim)/u) fwave(i,1,1) = 0.5d0*u*(Qi - Qihat + Qimhat - Qim) else if (mthsrc.eq.4) then c # f-wave using proper path integral Qihat = Qim*dexp(-(sigi-sigim)/u) fwave(i,1,1) = u*(Qi - Qihat) else write(6,*) '*** invalid mthsrc: ',mthsrc endif s(i,1) = u c # assumes u>0: amdq(i,1) = 0.d0 apdq(i,1) = fwave(i,1,1) 30 continue c return end