c
c
c =========================================================
       subroutine qinit(maxmx,meqn,mbc,mx,xlower,dx,q,maux,aux)
c =========================================================
c
c     # Set initial conditions for q.
c     # Standing wave for the acoustics equations.
c
c
      implicit double precision (a-h,o-z)
      dimension q(1-mbc:maxmx+mbc, meqn)
      dimension aux(1-mbc:maxmx+mbc, *)
      common /cqinit/ beta
c
c
      pi = 4.d0*datan(1.d0)
      do 150 i=1,mx
	 xcell = xlower + (i-0.5d0)*dx
	 q(i,1) = dcos(2.d0*pi*xcell)
	 q(i,2) = 0.d0
  150    continue
c
      return
      end