feat: runtime as library

exm/builtins/vdp.ml

@@ -0,0 +1,45 @@
+
+open Hsim.Types
+open Solvers.Zls
+
+let of_array a : carray =
+  Bigarray.Array1.of_array Bigarray.Float64 Bigarray.c_layout a
+
+type state = { lx : carray; i : bool }
+
+let mu = 5.0
+let x0 = 1.0
+let y0 = 1.0
+
+let csize = 2
+let zsize = 1
+
+let fder y yd =
+  yd.{0} <- y.{1};
+  yd.{1} <- (mu *. (1.0 -. (y.{0} *. y.{0})) *. y.{1}) -. y.{0};
+  yd
+let fout _ _ _ y = of_array [| y.{0}; y.{1} |]
+let step { i; lx } _ _ =
+  let lx = if i then of_array [| x0; y0 |] else lx in
+  of_array [| lx.{0}; lx.{1} |], { lx; i=false }
+let cget s    = s.lx
+let cset s lx = { s with lx }
+let zset s _  = s
+let jump _    = true
+let horizon _ = max_float
+
+let van_der_pol () : (_, _, carray, carray, carray, zarray, carray) hnode =
+  let yd         = cmake csize in
+  let zout       = cmake zsize in
+  let fder _ _ _ y = fder y yd in
+  let fzer _ _ _ _ = zout in
+  let state      = { lx=of_array [| x0; y0 |]; i=true } in
+  let reset _ _  = state in
+  HNode { state; fder; fzer; fout; step; reset; horizon;
+          jump; cset; cget; zset; csize; zsize }
+
+let errmsg = "Too many arguments for the model (needed: 0)"
+let init = function
+  | [] -> van_der_pol ()
+  | _  -> raise (Invalid_argument errmsg)
+