subroutine rtfuncs(npts,x,y,a)
c
c Subroutine to provide GRIDLS with the model visibilities
c
      include 'constnts.inc'
      include 'data.inc'
      include 'model.inc'
c
      integer*4 npts
      real*8 x(*),y(*),a(*),mseprad,mparad
c
      real*8 modvis2(mxscn,mxfilt),modphas(mxscn,mxfilt)
      real*8 u(mxscn,mxfilt),v(mxscn,mxfilt)
      real*8 mhours(mxscn),lambda(mxscn,mxfilt),dlambda(mxscn,mxfilt)
      integer*4 mdate(mxscn),mbaseline(mxscn)
c
      mseprad=a(1)
      mparad=a(2)
      ndat=npts/3      ! npts is exactly ndat*3
      do i=1,npts      ! copy appropriate section of data
       id=int(x(i))   
       ig=(i-1)/ndat+1
       iid=i-((i-1)/ndat)*ndat
       mdate(iid)=date(id)
       mbaseline(iid)=baseline(id)
       mhours(iid)=hours(id)
       lambda(iid,ig)=lambda0(id,ig)
       dlambda(iid,ig)=dlambda0(id,ig)
       u(iid,ig)=udata(id,ig)
       v(iid,ig)=vdata(id,ig)
      enddo
      mode=1
      call binavis(ndat,nfilt,mxscn,mxfilt,mdate,mbaseline,
     &             mhours,lambda,dlambda,modvis2,modphas,u,v,
     &             mseprad,mparad,mode,ftcurve)

      do i=1,npts
       id=i-((i-1)/ndat)*ndat
       ig=(i-1)/ndat+1
       y(i)=modvis2(id,ig)
      enddo
c
      return
      end