c      main program
       parameter(nx=11,ny=11,nx2=nx*2,nxy=nx*ny,ico=7)
       parameter(nx0=nx-1,ny0=ny-1,nxy0=nx0*ny0)
       parameter(nxa=nx0-1,nya=ny0-1)
       parameter(x0=0.0,y0=0.0,z0=0.0)
       parameter(xll=4.0,yll=4.0,zll=4.0)
       dimension v(nxy0),u(nxy),p(nx2)
c      icc=1:x-y plane, 2:y-z plane, 3:x-z plane
c
       pi=3.1415926
       amp=1.0
c
       do 100 ii=1,2
       do 10 j=1,ny0
       do 10 i=1,nx0
       i1=i+nx0*(j-1)
       if(ii.eq.1) v(i1)=0.5+float(i-1)
       if(ii.eq.2) v(i1)=0.5+float(j-1)
c      if(ii.eq.1) v(i1)=1.0+2.0*float(i-1)
c      if(ii.eq.2) v(i1)=1.0+2.0*float(j-1)
   10  continue
c
       call trans1(nx,ny,v,u)
c
       write(6,24)
       do 20 j=1,ny0
       i1=1+nx0*(j-1)
       i2=i1+nxa
       write(6,22) (v(i),i=i1,i2)
   22  format(1h ,11f4.1)
   24  format(1h )
   20  continue
c
       write(6,24)
       do 30 j=1,ny
       i1=1+nx*(j-1)
       i2=i1+nx0
       write(6,22) (u(i),i=i1,i2)
   30  continue
  100  continue
c
       stop
       end
c
c      subroutine trans1
       subroutine trans1(nx,ny,v,u)
       dimension v(1),u(1)
c
       nx0=nx-1
       ny0=ny-1
       nxa=nx0-1
       nya=ny0-1
c
       do 10 j=1,nya
       do 10 i=1,nxa
       i1=i+1+nx*j
       j1=i+nx0*(j-1)
       u(i1)=0.25*(v(j1)+v(j1+1)+v(j1+nx0)+v(j1+nx))
   10  continue
c
       do 20 i=1,nxa
       i1=i+1
       i2=i1+nx*ny0
       j1=i+1
       j2=i+1+nx0*nya
       u(i1)=0.75*(v(j1-1)+v(j1))-0.25*(v(j1-1+nx0)+v(j1+nx0))
       u(i2)=0.75*(v(j2-1)+v(j2))-0.25*(v(j2-1-nx0)+v(j2-nx0))
   20  continue
c
       do 30 j=1,nya
       i1=1+nx*j
       i2=i1+nx0
       j1=1+nx0*j
       j2=j1+nxa
       u(i1)=0.75*(v(j1-nx0)+v(j1))-0.25*(v(j1-nx0+1)+v(j1+1))
       u(i2)=0.75*(v(j2-nx0)+v(j2))-0.25*(v(j2-nx0-1)+v(j2-1))
   30  continue
c
       i1=1
       i2=i1+nx0
       i3=1+nx*ny0
       i4=i3+nx0
       j1=1
       j2=j1+nxa
       j3=1+nx0*nya
       j4=j3+nxa
       u(i1)=0.5*(3.0*v(j1)-v(j1+nx))
       u(i2)=0.5*(3.0*v(j2)-v(j2+nxa))
       u(i3)=0.5*(3.0*v(j3)-v(j3-nxa))
       u(i4)=0.5*(3.0*v(j4)-v(j4-nx))
c
       write(6,*) i1,i2,i3,i4
       write(6,*) j1,j2,j3,j4
       write(6,*) nx,nx0,nxa,ny,ny0,nya
c
       return
       end