let evalBinOp op e1 e2=
    let l1=Array.length e1 in
    let l2=Array.length e2 in
    if l1<l2 then begin
      let newe=Array.make l2 0.0 in
      for i=0 to l1 do
        newe.(i)<-e1.(i)
      done;
      let r=Array.iteri (fun i -> fun x-> x (binop op) newe.(i)) e2 in r
    end
    else begin
      let newe=Array.make l1 0.0 in
      for i=0 to l2 do
        newe.(i)<- e2.(i)
      done;
      let r=Array.iteri (fun i -> fun x-> x (binop op) newe.(i)) e1 in r
    end ;;