open Zls
open Odexx.Ode45

type state =
  { state: t; vec: carray; now: Full.time }

let make_full () : (carray, carray) Full.csolver =
  let state =
    let v = Zls.cmake 0 in
    let state = initialize (fun _ _ _ -> ()) (vec v) in
    set_stop_time state 1.0; { state; vec=v; now=0.0 } in
  let step ({ state ; vec=v; now } as s) h =
    let y_nv = vec v in
    let h = step state h y_nv in
    let state = copy state in
    let f t = get_dky state y_nv (now +. t) 0; unvec y_nv in
    { s with now=now +. h }, { Full.h=h -. now; f } in
  let reset _ Full.{ fder; y0; h } =
    let fder t cvec dvec = Zls.blit (fder t cvec) dvec in
    let state = initialize fder (vec y0) in
    set_stop_time state h;
    { state; vec = y0; now=0.0 } in
  Full.DNode { state; step; reset }

let make () : (carray, carray) Fill.csolver =
  let state =
    let v = Zls.cmake 0 in
    let state = initialize (fun _ _ _ -> ()) (vec v) in
    set_stop_time state 1.0; { state; vec=v; now=0.0 } in
  let step ({ state ; vec=v; now } as s) h =
    let y_nv = vec v in
    let h = step state h y_nv in
    let state = copy state in
    let f t = get_dky state y_nv (now +. t) 0; unvec y_nv in
    { s with now=now +. h }, { Fill.h=h -. now; f } in
  let reset _ Fill.{ fder; y0; h } =
    let fder t cvec dvec = Zls.blit (fder t cvec) dvec in
    let state = initialize fder (vec y0) in
    set_stop_time state h;
    { state; vec = y0; now=0.0 } in
  Fill.DNode { state; step; reset }