convert poseidon params from strings just once

src/lib/crypto/kimchi_backend/pasta/basic/kimchi_pasta_basic.ml

@@ -147,3 +147,9 @@ module Fp_poly_comm = Kimchi_backend_common.Poly_comm.Make (struct
      fun unshifted shifted : t -> { shifted; unshifted }
   end
 end)
+
+(* poseidon params *)
+
+let poseidon_params_fp = Sponge.Params.(map pasta_p_kimchi ~f:Fp.of_string)
+
+let poseidon_params_fq = Sponge.Params.(map pasta_q_kimchi ~f:Fq.of_string)

src/lib/crypto/kimchi_backend/pasta/constraint_system/caml/pallas_constraint_system.ml

@@ -4,8 +4,5 @@ open Kimchi_pasta_basic
 include
   Plonk_constraint_system.Make (Fq) (Kimchi_bindings.Protocol.Gates.Vector.Fq)
     (struct
-      let params =
-        Sponge.Params.(
-          map pasta_q_kimchi ~f:(fun x ->
-              Fq.of_bigint (Bigint256.of_decimal_string x) ))
+      let params = poseidon_params_fq
     end)

src/lib/crypto/kimchi_backend/pasta/constraint_system/caml/vesta_constraint_system.ml

@@ -4,8 +4,5 @@ open Kimchi_pasta_basic
 include
   Plonk_constraint_system.Make (Fp) (Kimchi_bindings.Protocol.Gates.Vector.Fp)
     (struct
-      let params =
-        Sponge.Params.(
-          map pasta_p_kimchi ~f:(fun x ->
-              Fp.of_bigint (Bigint256.of_decimal_string x) ))
+      let params = poseidon_params_fp
     end)

src/lib/pickles/step_main_inputs.ml

@@ -7,8 +7,7 @@ open Import
 
 let high_entropy_bits = 128
 
-let sponge_params_constant =
-  Sponge.Params.(map pasta_p_kimchi ~f:Impl.Field.Constant.of_string)
+let sponge_params_constant = Kimchi_pasta_basic.poseidon_params_fp
 
 let tick_field_random_oracle ?(length = Tick.Field.size_in_bits - 1) s =
   Tick.Field.of_bits (Ro.bits_random_oracle ~length s)

src/lib/pickles/tick_field_sponge.ml

@@ -1,10 +1,3 @@
 include Make_sponge.Make (Backend.Tick.Field)
 
-let params =
-  (* HACK *)
-  Sponge.Params.(
-    let testbit n i = Bigint.(equal (shift_right n i land one) one) in
-    map pasta_p_kimchi ~f:(fun s ->
-        Backend.Tick.Field.of_bits
-          (List.init Backend.Tick.Field.size_in_bits
-             (testbit (Bigint.of_string s)) ) ))
+let params = Kimchi_pasta_basic.poseidon_params_fp

src/lib/pickles/tock_field_sponge.ml

@@ -1,10 +1,3 @@
 include Make_sponge.Make (Backend.Tock.Field)
 
-let params =
-  (* HACK *)
-  Sponge.Params.(
-    let testbit n i = Bigint.(equal (shift_right n i land one) one) in
-    map pasta_q_kimchi ~f:(fun s ->
-        Backend.Tock.Field.of_bits
-          (List.init Backend.Tock.Field.size_in_bits
-             (testbit (Bigint.of_string s)) ) ))
+let params = Kimchi_pasta_basic.poseidon_params_fq

src/lib/pickles/wrap_main_inputs.ml

@@ -9,8 +9,7 @@ open Import
 
 let high_entropy_bits = 128
 
-let sponge_params_constant =
-  Sponge.Params.(map pasta_q_kimchi ~f:Impl.Field.Constant.of_string)
+let sponge_params_constant = Kimchi_pasta_basic.poseidon_params_fq
 
 let field_random_oracle ?(length = Me.Field.size_in_bits - 1) s =
   Me.Field.of_bits (Ro.bits_random_oracle ~length s)

src/lib/random_oracle/permutation/external/random_oracle_permutation.ml

@@ -17,7 +17,7 @@ let block_cipher _params (s : Field.t array) =
 
 let%test_unit "check rust implementation of block-cipher" =
   let params' : Field.t Sponge.Params.t =
-    Sponge.Params.(map pasta_p_kimchi ~f:Field.of_string)
+    Kimchi_pasta_basic.poseidon_params_fp
   in
   let open Pickles.Impls.Step in
   let module T = Internal_Basic in

src/lib/random_oracle/random_oracle.ml

@@ -20,8 +20,7 @@ end
 
 module Input = Random_oracle_input
 
-let params : Field.t Sponge.Params.t =
-  Sponge.Params.(map pasta_p_kimchi ~f:Field.of_string)
+let params : Field.t Sponge.Params.t = Kimchi_pasta_basic.poseidon_params_fp
 
 module Operations = struct
   let add_assign ~state i x = Field.(state.(i) <- state.(i) + x)