From 8d498c587aaa23dcb50c31fa5a426873b3dd9dea Mon Sep 17 00:00:00 2001
From: Andres Erbsen <andreser@mit.edu>
Date: Mon, 20 Jun 2016 04:16:04 -0400
Subject: move nsatz into tactics directory

---
 src/Tactics/Nsatz.v | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 src/Tactics/Nsatz.v

(limited to 'src/Tactics')

diff --git a/src/Tactics/Nsatz.v b/src/Tactics/Nsatz.v
new file mode 100644
index 000000000..469ba4c29
--- /dev/null
+++ b/src/Tactics/Nsatz.v
@@ -0,0 +1,120 @@
+(*** Tactics for manipulating polynomial equations *)
+Require Coq.nsatz.Nsatz.
+Require Import List.
+
+Generalizable All Variables.
+Lemma cring_sub_diag_iff {R zero eq sub} `{cring:Cring.Cring (R:=R) (ring0:=zero) (ring_eq:=eq) (sub:=sub)}
+  : forall x y, eq (sub x y) zero <-> eq x y.
+Proof.
+  split;intros Hx.
+  { eapply Nsatz.psos_r1b. eapply Hx. }
+  { eapply Nsatz.psos_r1. eapply Hx. }
+Qed.
+
+Ltac get_goal := lazymatch goal with |- ?g => g end.
+
+Ltac nsatz_equation_implications_to_list eq zero g :=
+  lazymatch g with
+  | eq ?p zero => constr:(p::nil)
+  | eq ?p zero -> ?g => let l := nsatz_equation_implications_to_list eq zero g in constr:(p::l)
+  end.
+
+Ltac nsatz_reify_equations eq zero :=
+  let g := get_goal in
+  let lb := nsatz_equation_implications_to_list eq zero g in
+  lazymatch (eval red in (Ncring_tac.list_reifyl (lterm:=lb))) with
+    (?variables, ?le) =>
+    lazymatch (eval compute in (List.rev le)) with
+    | ?reified_goal::?reified_givens => constr:(variables, reified_givens, reified_goal)
+    end
+  end.
+
+Ltac nsatz_get_free_variables reified_package :=
+  lazymatch reified_package with (?fv, _, _) => fv end.
+
+Ltac nsatz_get_reified_givens reified_package :=
+  lazymatch reified_package with (_, ?givens, _) => givens end.
+
+Ltac nsatz_get_reified_goal reified_package :=
+  lazymatch reified_package with (_, _, ?goal) => goal end.
+
+Require Import Coq.setoid_ring.Ring_polynom.
+Ltac nsatz_compute_to_goal sugar nparams reified_goal power reified_givens :=
+  nsatz_compute (PEc sugar :: PEc nparams :: PEpow reified_goal power :: reified_givens).
+
+Ltac nsatz_compute_get_leading_coefficient :=
+  lazymatch goal with
+    |- Logic.eq ((?a :: _ :: ?b) :: ?c) _ -> _ => a
+  end.
+
+Ltac nsatz_compute_get_certificate :=
+  lazymatch goal with
+    |- Logic.eq ((?a :: _ :: ?b) :: ?c) _ -> _ => constr:(c,b)
+  end.
+
+Ltac nsatz_rewrite_and_revert domain :=
+  lazymatch type of domain with
+  | @Integral_domain.Integral_domain ?F ?zero _ _ _ _ _ ?eq ?Fops ?FRing ?FCring =>
+    lazymatch goal with
+    | |- eq _ zero => idtac
+    | |- eq _ _ => rewrite <-(cring_sub_diag_iff (cring:=FCring))
+    end;
+    repeat match goal with
+           | [H : eq _ zero |- _ ] => revert H
+           | [H : eq _ _ |- _ ] => rewrite <-(cring_sub_diag_iff (cring:=FCring)) in H; revert H
+           end
+  end.
+  
+Ltac nsatz_nonzero := 
+  try solve [apply Integral_domain.integral_domain_one_zero
+            |apply Integral_domain.integral_domain_minus_one_zero
+            |trivial].
+
+Ltac nsatz_domain_sugar_power domain sugar power := 
+  let nparams := constr:(BinInt.Zneg BinPos.xH) in (* some symbols can be "parameters", treated as coefficients *)
+  lazymatch type of domain with
+  | @Integral_domain.Integral_domain ?F ?zero _ _ _ _ _ ?eq ?Fops ?FRing ?FCring =>
+    nsatz_rewrite_and_revert domain;
+    let reified_package := nsatz_reify_equations eq zero in
+    let fv := nsatz_get_free_variables reified_package in
+    let interp := constr:(@Nsatz.PEevalR _ _ _ _ _ _ _ _ Fops fv) in
+    let reified_givens := nsatz_get_reified_givens reified_package in
+    let reified_goal := nsatz_get_reified_goal reified_package in
+    nsatz_compute_to_goal sugar nparams reified_goal power reified_givens;
+    let a := nsatz_compute_get_leading_coefficient in
+    let crt := nsatz_compute_get_certificate in
+    intros _ (* discard [nsatz_compute] output *); intros;
+    apply (fun Haa refl cond => @Integral_domain.Rintegral_domain_pow _ _ _ _ _ _ _ _ _ _ _ domain (interp a) _ (BinNat.N.to_nat power) Haa (@Nsatz.check_correct _ _ _ _ _ _ _ _ _ _ FCring fv reified_givens (PEmul a (PEpow reified_goal power)) crt refl cond));
+    [ nsatz_nonzero; cbv iota beta delta [Nsatz.PEevalR PEeval InitialRing.gen_phiZ InitialRing.gen_phiPOS]
+    | solve [vm_compute; exact (eq_refl true)] (* exact_no_check (eq_refl true) *)
+    | solve [repeat (split; [assumption|]); exact I] ]
+  end.
+
+Ltac nsatz_guess_domain :=
+  match goal with
+  | |- ?eq _ _ => constr:(_:Integral_domain.Integral_domain (ring_eq:=eq))
+  | |- not (?eq _ _) =>  constr:(_:Integral_domain.Integral_domain (ring_eq:=eq))
+  | [H: ?eq _ _ |- _ ] =>  constr:(_:Integral_domain.Integral_domain (ring_eq:=eq))
+  | [H: not (?eq _ _) |- _] =>  constr:(_:Integral_domain.Integral_domain (ring_eq:=eq))
+  end.
+
+Ltac nsatz_sugar_power sugar power :=
+  let domain := nsatz_guess_domain in
+  nsatz_domain_sugar_power domain sugar power.
+
+Tactic Notation "nsatz" constr(n) :=
+  let nn := (eval compute in (BinNat.N.of_nat n)) in
+  nsatz_sugar_power BinInt.Z0 nn.
+
+Tactic Notation "nsatz" := nsatz 1%nat || nsatz 2%nat || nsatz 3%nat || nsatz 4%nat || nsatz 5%nat.
+
+Ltac nsatz_contradict :=
+  unfold not;
+  intros;
+  let domain := nsatz_guess_domain in
+  lazymatch type of domain with
+  | @Integral_domain.Integral_domain _ ?zero ?one _ _ _ _ ?eq ?Fops ?FRing ?FCring =>
+    assert (eq one zero) as Hbad;
+    [nsatz; nsatz_nonzero
+    |destruct (Integral_domain.integral_domain_one_zero (Integral_domain:=domain) Hbad)]
+  end.
\ No newline at end of file
-- 
cgit v1.2.3