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Very early and incomplete work in progress on using classical control…
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… flow in compiled QASM
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@mikhailmints
mikhailmints committed Sep 21, 2024
1 parent 08d8653 commit b9ab8f1
Showing 1 changed file with 71 additions and 16 deletions.
87 changes: 71 additions & 16 deletions lib/compilation.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,9 @@ type inter_op =
| IContextMerge of context * context
(** Merges contexts assumed to be disjoint, ensuring proper ordering of
variables. *)
| IClassicalTryCatch of inter_op * inter_op
(** Measures the flag register output by the first operator, and if it is
nonzero, replaces the output with that of the second operator. *)
| ILambda of
string * (string * int) list * inter_com list * (string * int) list
(** A user-defined operator. Consists of a name, a list of argument names
Expand Down Expand Up @@ -1259,6 +1262,48 @@ let circuit_pure_error_handling (cs : circuit_spec) : circuit_spec =
end;
}

(** Measures the flag register output by the first circuit, and if it is
nonzero, replaces the output with that of the second circuit. *)
let circuit_classical_try_catch (cs0 : circuit_spec) (cs1 : circuit_spec) :
circuit_spec =
if cs0.in_sizes <> cs1.in_sizes || cs0.out_sizes <> cs1.out_sizes then
failwith "circuit_classical_try_catch: expected matching sizes";
{
in_sizes = cs0.in_sizes;
out_sizes = cs0.out_sizes;
circ_fun =
begin
fun in_regs used_wires settings ->
let circ0, used_wires0 =
build_circuit cs0 in_regs used_wires settings
in
let circ1, used_wires1 =
build_circuit cs1 in_regs used_wires settings
in
(* let out_regs, used_wires = fresh_int_lists used_wires cs0.out_sizes in
let flag_reg, used_wires = fresh_int_list (List.length circ1.flag_reg) in *)
( {
name = "classical_try_catch";
in_regs;
prep_reg = int_list_union circ0.prep_reg circ1.prep_reg;
out_regs = circ0.out_regs;
flag_reg = circ1.flag_reg;
garb_reg = int_list_union circ0.garb_reg circ1.garb_reg;
gate =
gate_if_reg_nonzero circ0.flag_reg circ0.gate
(List.fold_left ( @& ) Identity
(List.map gate_reset_reg
(circ0.out_regs @ [circ0.flag_reg]))
@& circ1.gate
@& List.fold_left ( @& ) Identity
(List.map
(fun (a, b) -> gate_swap_regs a b)
(List.combine circ1.out_regs circ0.out_regs)));
},
used_wires )
end;
}

(** Relative phase circuit, using a given circuit specification to define a
subspace of the given type - different phases are applied to states inside
and outside the subspace. *)
Expand Down Expand Up @@ -1623,6 +1668,10 @@ and compile_inter_op_to_circuit (op : inter_op) : circuit_spec =
circuit_mark_as_iso iso (compile_inter_op_to_circuit op')
| IContextPartition (d, fv) -> circuit_context_partition d fv
| IContextMerge (d0, d1) -> circuit_context_merge d0 d1
| IClassicalTryCatch (op0, op1) ->
circuit_classical_try_catch
(compile_inter_op_to_circuit op0)
(compile_inter_op_to_circuit op1)
| IAdjoint (IAdjoint op) -> compile_inter_op_to_circuit op
| IAdjoint (ISequence (op0, op1)) ->
compile_inter_op_to_circuit (ISequence (IAdjoint op1, IAdjoint op0))
Expand Down Expand Up @@ -2382,7 +2431,7 @@ and compile_pure_expr_to_inter_op (tp : pure_expr_typing_proof) : inter_op =
]
[("g", gsize); ("res", 0)]
else
let e_op = compile_mixed_expr_to_inter_op e in
let e_op = compile_mixed_expr_to_inter_op e false in
let gjs = List.map fst3 l in
let ej's = List.map trd3 l in
let ortho_op, ortho_tree, _ = compile_ortho_to_inter_op orp in
Expand Down Expand Up @@ -2456,7 +2505,8 @@ and compile_pure_expr_to_inter_op (tp : pure_expr_typing_proof) : inter_op =
(** Compiles a mixed expression into the intermediate representation. This
creates a circuit that takes in one register, corresponding to the quantum
context. *)
and compile_mixed_expr_to_inter_op (tp : mixed_expr_typing_proof) : inter_op =
and compile_mixed_expr_to_inter_op (tp : mixed_expr_typing_proof)
(classical : bool) : inter_op =
let t = type_of_mixed_expr_proof tp in
let g_whole, d_whole = context_of_mixed_expr_proof tp in
let gsize = context_size g_whole in
Expand All @@ -2475,7 +2525,7 @@ and compile_mixed_expr_to_inter_op (tp : mixed_expr_typing_proof) : inter_op =
[("g", gsize); ("res", tsize)]
end
| TDiscard { d; d0; e; iso; _ } -> begin
let e_op = compile_mixed_expr_to_inter_op e in
let e_op = compile_mixed_expr_to_inter_op e classical in
inter_lambda_marked "TDiscard" iso false
[("g", gsize); ("dd0", dsize)]
[
Expand All @@ -2490,8 +2540,8 @@ and compile_mixed_expr_to_inter_op (tp : mixed_expr_typing_proof) : inter_op =
[("g", gsize); ("res", tsize)]
end
| TMixedPair { t0; t1; d; d0; d1; e0; e1; iso; _ } -> begin
let op0 = compile_mixed_expr_to_inter_op e0 in
let op1 = compile_mixed_expr_to_inter_op e1 in
let op0 = compile_mixed_expr_to_inter_op e0 classical in
let op1 = compile_mixed_expr_to_inter_op e1 classical in
inter_lambda_marked "TMixedPair" iso false
[("g", gsize); ("dd0d1", dsize)]
[
Expand Down Expand Up @@ -2525,11 +2575,13 @@ and compile_mixed_expr_to_inter_op (tp : mixed_expr_typing_proof) : inter_op =
]
[("g", gsize); ("res", 0)]
else
let e_op = compile_mixed_expr_to_inter_op e in
let e_op = compile_mixed_expr_to_inter_op e false in
let gjs = List.map fst3 l in
let ej's = List.map trd3 l in
let ortho_op, ortho_tree, _ = compile_ortho_to_inter_op orp in
let ej'_ops = List.map compile_mixed_expr_to_inter_op ej's in
let ej'_ops =
List.map (fun x -> compile_mixed_expr_to_inter_op x false) ej's
in
let garb_sizes =
List.map
begin
Expand Down Expand Up @@ -2659,12 +2711,14 @@ and compile_mixed_expr_to_inter_op (tp : mixed_expr_typing_proof) : inter_op =
[("g", gsize); ("t1", tsize)]
end
| TTry { t; d0; e0; e1; iso; _ } -> begin
let op0 = compile_mixed_expr_to_inter_op e0 in
let op1 = compile_mixed_expr_to_inter_op e1 in
let op0 = compile_mixed_expr_to_inter_op e0 classical in
let op1 = compile_mixed_expr_to_inter_op e1 classical in
let iso0 = is_iso_mixed_expr_proof e0 in
let iso1 = is_iso_mixed_expr_proof e1 in
if iso0 then
compile_mixed_expr_to_inter_op e0
if classical then
IClassicalTryCatch (op0, op1)
else if iso0 then
op0
else if iso1 then
inter_lambda_marked "TTry" iso false
[("g", gsize); ("d", dsize)]
Expand Down Expand Up @@ -2716,8 +2770,8 @@ and compile_mixed_expr_to_inter_op (tp : mixed_expr_typing_proof) : inter_op =
[("g", gsize); ("t", tsize)]
end
| TMixedApp { f; e; iso; _ } -> begin
let e_op = compile_mixed_expr_to_inter_op e in
let f_op = compile_mixed_prog_to_inter_op f in
let e_op = compile_mixed_expr_to_inter_op e classical in
let f_op = compile_mixed_prog_to_inter_op f classical in
inter_lambda_marked "TMixedApp" iso false
[("g", gsize); ("d", dsize)]
[
Expand Down Expand Up @@ -2774,12 +2828,13 @@ and compile_pure_prog_to_inter_op (tp : pure_prog_typing_proof) : inter_op =
end

(** Compiles a mixed program into the intermediate representation. *)
and compile_mixed_prog_to_inter_op (tp : mixed_prog_typing_proof) : inter_op =
and compile_mixed_prog_to_inter_op (tp : mixed_prog_typing_proof)
(classical : bool) : inter_op =
match tp with
| TChannel tp' -> compile_pure_prog_to_inter_op tp'
| TMixedAbs { t; t'; e; e'; iso; _ } -> begin
let e_op = compile_pure_expr_to_inter_op e in
let e'_op = compile_mixed_expr_to_inter_op e' in
let e'_op = compile_mixed_expr_to_inter_op e' classical in
inter_lambda_marked "TMixedAbs" iso false
[("t", type_size t)]
[
Expand All @@ -2799,7 +2854,7 @@ and compile_mixed_prog_to_inter_op (tp : mixed_prog_typing_proof) : inter_op =
circuit's gate and additional relevant information. *)
let expr_compile (e : expr) : gate * int * int list =
let tp = mixed_type_check_noopt e in
let op = compile_mixed_expr_to_inter_op tp in
let op = compile_mixed_expr_to_inter_op tp true in
let cs = compile_inter_op_to_circuit op in
let circ, _ =
build_circuit cs [[]; []] IntSet.empty
Expand Down

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