program define z_rcopy
*!  version 1.1.1 02Feb96

   version 4.0
   local options "TO(string) FROM(string)"
   parse "`*'"

   if "`to'" != "" {
      if "`from'" == "" {
         z_rvrfy S_1 S_2 S_3
         local ww : word 1 of `to'
         matrix `ww' = S_1
         local ww : word 2 of `to'
         matrix `ww' = S_2
         local ww : word 3 of `to'
         matrix `ww' = S_3
         exit
      }
   }
   else if "`from'" != "" {
      z_rvrfy `from'
      local ww : word 1 of `from'
      matrix S_1 = `ww'
      local ww : word 2 of `from'
      matrix S_2 = `ww'
      local ww : word 3 of `from'
      matrix S_3 = `ww'
      exit
   }
   di in red "exactly one of to(`to') and from(`from') must be present"
   error 499
end