getmaxspeed_geo.f.html
Source file:   getmaxspeed_geo.f
Directory:   /home/rjl/git/rjleveque/clawpack-4.x/geoclaw/2d/lib
Converted:   Sun May 15 2011 at 19:15:40   using clawcode2html
This documentation file will not reflect any later changes in the source file.

 

c
c -----------------------------------------------------------------------------
c
      double precision function get_max_speed(val,mitot,mjtot,nvar,
     &                          aux,naux,nghost,hx,hy)

      use geoclaw_module
      implicit double precision (a-h,o-z)
      dimension   val(mitot,mjtot,nvar), aux(mitot,mjtot,naux)


      sp_over_h = 0.d0   ! compute max speed over h, since dx may not equal dy
      if (icoordsys .eq. 2) then
        do j = nghost+1, mjtot-nghost
         ymetric = Rearth*pi/180.d0
         hyphys = ymetric*hy

         do i = nghost+1, mitot-nghost
            xmetric = cos(aux(i,j,3))*Rearth*pi/180.d0
            hxphys = xmetric * hx
            h  = val(i,j,1)
            if (h .gt. drytolerance) then
              u  = val(i,j,2)/h
              v  = val(i,j,3)/h
            else
              u = 0.d0
              v = 0.d0
            endif
            sig = sqrt(grav*h)
            sp_over_h = max((abs(u)+sig)/hxphys,(abs(v)+sig)/hyphys,
     &                      sp_over_h)
         end do
         end do
      else  ! speeds in cartesian coords, no metrics needed
         do j = nghost+1, mjtot-nghost
         do i = nghost+1, mitot-nghost
            h  = val(i,j,1)
            if (h .gt. drytolerance) then
              u  = val(i,j,2)/h
              v  = val(i,j,3)/h
            else
              u = 0.d0
              v = 0.d0
            endif
            sig = sqrt(grav*h)
            sp_over_h = max((abs(u)+sig)/hx,(abs(v)+sig)/hy,sp_over_h)
         end do
         end do
      endif

       get_max_speed = sp_over_h

       return
       end