c
c
c
c     =====================================================
       subroutine qinit(maxmx,maxmy,maxmz,meqn,mbc,mx,my,mz,
     &                   xlower,ylower,zlower,dx,dy,dz,q,maux,aux)
c     =====================================================
c
c     # Set initial conditions for q.
c
       implicit double precision (a-h,o-z)
c
       dimension q(1-mbc:maxmx+mbc, 1-mbc:maxmy+mbc,
     &             1-mbc:maxmz+mbc, meqn)
c
c     # set concentration profile
c     ---------------------------
c
      do 215 i=1,mx
         xcell = xlower + (i-0.5d0)*dx
         do 210 j=1,my
            ycell = ylower + (j-0.5d0)*dy
            do 205 k=1,mz
               zcell = zlower + (k-0.5d0)*dz
               if (xcell .gt. 0.1d0 .and. xcell .lt. 0.5d0 .and.
     &             ycell .gt. 0.1d0 .and. ycell .lt. 0.5d0 .and.
     &             zcell .gt. 0.1d0 .and. zcell .lt. 0.5d0) then
                       q(i,j,k,1) = 1.d0
                    else
                       q(i,j,k,1) = 0.d0
                    endif
  205           continue
  210        continue
  215     continue
       return
       end