--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Tools/int_factor_simprocs.ML Wed Dec 03 15:58:44 2008 +0100
@@ -0,0 +1,340 @@
+(* Title: HOL/int_factor_simprocs.ML
+ ID: $Id$
+ Author: Lawrence C Paulson, Cambridge University Computer Laboratory
+ Copyright 2000 University of Cambridge
+
+Factor cancellation simprocs for the integers (and for fields).
+
+This file can't be combined with int_arith1 because it requires IntDiv.thy.
+*)
+
+
+(*To quote from Provers/Arith/cancel_numeral_factor.ML:
+
+Cancels common coefficients in balanced expressions:
+
+ u*#m ~~ u'*#m' == #n*u ~~ #n'*u'
+
+where ~~ is an appropriate balancing operation (e.g. =, <=, <, div, /)
+and d = gcd(m,m') and n=m/d and n'=m'/d.
+*)
+
+val rel_number_of = [@{thm eq_number_of_eq}, @{thm less_number_of_eq_neg}, @{thm le_number_of_eq}];
+
+local
+ open Int_Numeral_Simprocs
+in
+
+structure CancelNumeralFactorCommon =
+ struct
+ val mk_coeff = mk_coeff
+ val dest_coeff = dest_coeff 1
+ val trans_tac = fn _ => trans_tac
+
+ val norm_ss1 = HOL_ss addsimps minus_from_mult_simps @ mult_1s
+ val norm_ss2 = HOL_ss addsimps simps @ mult_minus_simps
+ val norm_ss3 = HOL_ss addsimps @{thms mult_ac}
+ fun norm_tac ss =
+ ALLGOALS (simp_tac (Simplifier.inherit_context ss norm_ss1))
+ THEN ALLGOALS (simp_tac (Simplifier.inherit_context ss norm_ss2))
+ THEN ALLGOALS (simp_tac (Simplifier.inherit_context ss norm_ss3))
+
+ val numeral_simp_ss = HOL_ss addsimps rel_number_of @ simps
+ fun numeral_simp_tac ss = ALLGOALS (simp_tac (Simplifier.inherit_context ss numeral_simp_ss))
+ val simplify_meta_eq = Int_Numeral_Simprocs.simplify_meta_eq
+ [@{thm add_0}, @{thm add_0_right}, @{thm mult_zero_left},
+ @{thm mult_zero_right}, @{thm mult_Bit1}, @{thm mult_1_right}];
+ end
+
+(*Version for integer division*)
+structure IntDivCancelNumeralFactor = CancelNumeralFactorFun
+ (open CancelNumeralFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binop @{const_name Divides.div}
+ val dest_bal = HOLogic.dest_bin @{const_name Divides.div} HOLogic.intT
+ val cancel = @{thm zdiv_zmult_zmult1} RS trans
+ val neg_exchanges = false
+)
+
+(*Version for fields*)
+structure DivideCancelNumeralFactor = CancelNumeralFactorFun
+ (open CancelNumeralFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binop @{const_name HOL.divide}
+ val dest_bal = HOLogic.dest_bin @{const_name HOL.divide} Term.dummyT
+ val cancel = @{thm mult_divide_mult_cancel_left} RS trans
+ val neg_exchanges = false
+)
+
+structure EqCancelNumeralFactor = CancelNumeralFactorFun
+ (open CancelNumeralFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_eq
+ val dest_bal = HOLogic.dest_bin "op =" Term.dummyT
+ val cancel = @{thm mult_cancel_left} RS trans
+ val neg_exchanges = false
+)
+
+structure LessCancelNumeralFactor = CancelNumeralFactorFun
+ (open CancelNumeralFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binrel @{const_name HOL.less}
+ val dest_bal = HOLogic.dest_bin @{const_name HOL.less} Term.dummyT
+ val cancel = @{thm mult_less_cancel_left} RS trans
+ val neg_exchanges = true
+)
+
+structure LeCancelNumeralFactor = CancelNumeralFactorFun
+ (open CancelNumeralFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binrel @{const_name HOL.less_eq}
+ val dest_bal = HOLogic.dest_bin @{const_name HOL.less_eq} Term.dummyT
+ val cancel = @{thm mult_le_cancel_left} RS trans
+ val neg_exchanges = true
+)
+
+val cancel_numeral_factors =
+ map Int_Numeral_Base_Simprocs.prep_simproc
+ [("ring_eq_cancel_numeral_factor",
+ ["(l::'a::{idom,number_ring}) * m = n",
+ "(l::'a::{idom,number_ring}) = m * n"],
+ K EqCancelNumeralFactor.proc),
+ ("ring_less_cancel_numeral_factor",
+ ["(l::'a::{ordered_idom,number_ring}) * m < n",
+ "(l::'a::{ordered_idom,number_ring}) < m * n"],
+ K LessCancelNumeralFactor.proc),
+ ("ring_le_cancel_numeral_factor",
+ ["(l::'a::{ordered_idom,number_ring}) * m <= n",
+ "(l::'a::{ordered_idom,number_ring}) <= m * n"],
+ K LeCancelNumeralFactor.proc),
+ ("int_div_cancel_numeral_factors",
+ ["((l::int) * m) div n", "(l::int) div (m * n)"],
+ K IntDivCancelNumeralFactor.proc),
+ ("divide_cancel_numeral_factor",
+ ["((l::'a::{division_by_zero,field,number_ring}) * m) / n",
+ "(l::'a::{division_by_zero,field,number_ring}) / (m * n)",
+ "((number_of v)::'a::{division_by_zero,field,number_ring}) / (number_of w)"],
+ K DivideCancelNumeralFactor.proc)];
+
+(* referenced by rat_arith.ML *)
+val field_cancel_numeral_factors =
+ map Int_Numeral_Base_Simprocs.prep_simproc
+ [("field_eq_cancel_numeral_factor",
+ ["(l::'a::{field,number_ring}) * m = n",
+ "(l::'a::{field,number_ring}) = m * n"],
+ K EqCancelNumeralFactor.proc),
+ ("field_cancel_numeral_factor",
+ ["((l::'a::{division_by_zero,field,number_ring}) * m) / n",
+ "(l::'a::{division_by_zero,field,number_ring}) / (m * n)",
+ "((number_of v)::'a::{division_by_zero,field,number_ring}) / (number_of w)"],
+ K DivideCancelNumeralFactor.proc)]
+
+end;
+
+Addsimprocs cancel_numeral_factors;
+
+(*examples:
+print_depth 22;
+set timing;
+set trace_simp;
+fun test s = (Goal s; by (Simp_tac 1));
+
+test "9*x = 12 * (y::int)";
+test "(9*x) div (12 * (y::int)) = z";
+test "9*x < 12 * (y::int)";
+test "9*x <= 12 * (y::int)";
+
+test "-99*x = 132 * (y::int)";
+test "(-99*x) div (132 * (y::int)) = z";
+test "-99*x < 132 * (y::int)";
+test "-99*x <= 132 * (y::int)";
+
+test "999*x = -396 * (y::int)";
+test "(999*x) div (-396 * (y::int)) = z";
+test "999*x < -396 * (y::int)";
+test "999*x <= -396 * (y::int)";
+
+test "-99*x = -81 * (y::int)";
+test "(-99*x) div (-81 * (y::int)) = z";
+test "-99*x <= -81 * (y::int)";
+test "-99*x < -81 * (y::int)";
+
+test "-2 * x = -1 * (y::int)";
+test "-2 * x = -(y::int)";
+test "(-2 * x) div (-1 * (y::int)) = z";
+test "-2 * x < -(y::int)";
+test "-2 * x <= -1 * (y::int)";
+test "-x < -23 * (y::int)";
+test "-x <= -23 * (y::int)";
+*)
+
+(*And the same examples for fields such as rat or real:
+test "0 <= (y::rat) * -2";
+test "9*x = 12 * (y::rat)";
+test "(9*x) / (12 * (y::rat)) = z";
+test "9*x < 12 * (y::rat)";
+test "9*x <= 12 * (y::rat)";
+
+test "-99*x = 132 * (y::rat)";
+test "(-99*x) / (132 * (y::rat)) = z";
+test "-99*x < 132 * (y::rat)";
+test "-99*x <= 132 * (y::rat)";
+
+test "999*x = -396 * (y::rat)";
+test "(999*x) / (-396 * (y::rat)) = z";
+test "999*x < -396 * (y::rat)";
+test "999*x <= -396 * (y::rat)";
+
+test "(- ((2::rat) * x) <= 2 * y)";
+test "-99*x = -81 * (y::rat)";
+test "(-99*x) / (-81 * (y::rat)) = z";
+test "-99*x <= -81 * (y::rat)";
+test "-99*x < -81 * (y::rat)";
+
+test "-2 * x = -1 * (y::rat)";
+test "-2 * x = -(y::rat)";
+test "(-2 * x) / (-1 * (y::rat)) = z";
+test "-2 * x < -(y::rat)";
+test "-2 * x <= -1 * (y::rat)";
+test "-x < -23 * (y::rat)";
+test "-x <= -23 * (y::rat)";
+*)
+
+
+(** Declarations for ExtractCommonTerm **)
+
+local
+ open Int_Numeral_Simprocs
+in
+
+(*Find first term that matches u*)
+fun find_first_t past u [] = raise TERM ("find_first_t", [])
+ | find_first_t past u (t::terms) =
+ if u aconv t then (rev past @ terms)
+ else find_first_t (t::past) u terms
+ handle TERM _ => find_first_t (t::past) u terms;
+
+(** Final simplification for the CancelFactor simprocs **)
+val simplify_one = Int_Numeral_Simprocs.simplify_meta_eq
+ [@{thm mult_1_left}, @{thm mult_1_right}, @{thm zdiv_1}, @{thm numeral_1_eq_1}];
+
+fun cancel_simplify_meta_eq cancel_th ss th =
+ simplify_one ss (([th, cancel_th]) MRS trans);
+
+structure CancelFactorCommon =
+ struct
+ val mk_sum = long_mk_prod
+ val dest_sum = dest_prod
+ val mk_coeff = mk_coeff
+ val dest_coeff = dest_coeff
+ val find_first = find_first_t []
+ val trans_tac = fn _ => trans_tac
+ val norm_ss = HOL_ss addsimps mult_1s @ @{thms mult_ac}
+ fun norm_tac ss = ALLGOALS (simp_tac (Simplifier.inherit_context ss norm_ss))
+ end;
+
+(*mult_cancel_left requires a ring with no zero divisors.*)
+structure EqCancelFactor = ExtractCommonTermFun
+ (open CancelFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_eq
+ val dest_bal = HOLogic.dest_bin "op =" Term.dummyT
+ val simplify_meta_eq = cancel_simplify_meta_eq @{thm mult_cancel_left}
+);
+
+(*zdiv_zmult_zmult1_if is for integer division (div).*)
+structure IntDivCancelFactor = ExtractCommonTermFun
+ (open CancelFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binop @{const_name Divides.div}
+ val dest_bal = HOLogic.dest_bin @{const_name Divides.div} HOLogic.intT
+ val simplify_meta_eq = cancel_simplify_meta_eq @{thm zdiv_zmult_zmult1_if}
+);
+
+structure IntModCancelFactor = ExtractCommonTermFun
+ (open CancelFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binop @{const_name Divides.mod}
+ val dest_bal = HOLogic.dest_bin @{const_name Divides.mod} HOLogic.intT
+ val simplify_meta_eq = cancel_simplify_meta_eq @{thm zmod_zmult_zmult1}
+);
+
+structure IntDvdCancelFactor = ExtractCommonTermFun
+ (open CancelFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binrel @{const_name Ring_and_Field.dvd}
+ val dest_bal = HOLogic.dest_bin @{const_name Ring_and_Field.dvd} HOLogic.intT
+ val simplify_meta_eq = cancel_simplify_meta_eq @{thm zdvd_zmult_cancel_disj}
+);
+
+(*Version for all fields, including unordered ones (type complex).*)
+structure DivideCancelFactor = ExtractCommonTermFun
+ (open CancelFactorCommon
+ val prove_conv = Int_Numeral_Base_Simprocs.prove_conv
+ val mk_bal = HOLogic.mk_binop @{const_name HOL.divide}
+ val dest_bal = HOLogic.dest_bin @{const_name HOL.divide} Term.dummyT
+ val simplify_meta_eq = cancel_simplify_meta_eq @{thm mult_divide_mult_cancel_left_if}
+);
+
+val cancel_factors =
+ map Int_Numeral_Base_Simprocs.prep_simproc
+ [("ring_eq_cancel_factor",
+ ["(l::'a::{idom}) * m = n",
+ "(l::'a::{idom}) = m * n"],
+ K EqCancelFactor.proc),
+ ("int_div_cancel_factor",
+ ["((l::int) * m) div n", "(l::int) div (m * n)"],
+ K IntDivCancelFactor.proc),
+ ("int_mod_cancel_factor",
+ ["((l::int) * m) mod n", "(l::int) mod (m * n)"],
+ K IntModCancelFactor.proc),
+ ("int_dvd_cancel_factor",
+ ["((l::int) * m) dvd n", "(l::int) dvd (m * n)"],
+ K IntDvdCancelFactor.proc),
+ ("divide_cancel_factor",
+ ["((l::'a::{division_by_zero,field}) * m) / n",
+ "(l::'a::{division_by_zero,field}) / (m * n)"],
+ K DivideCancelFactor.proc)];
+
+end;
+
+Addsimprocs cancel_factors;
+
+
+(*examples:
+print_depth 22;
+set timing;
+set trace_simp;
+fun test s = (Goal s; by (Asm_simp_tac 1));
+
+test "x*k = k*(y::int)";
+test "k = k*(y::int)";
+test "a*(b*c) = (b::int)";
+test "a*(b*c) = d*(b::int)*(x*a)";
+
+test "(x*k) div (k*(y::int)) = (uu::int)";
+test "(k) div (k*(y::int)) = (uu::int)";
+test "(a*(b*c)) div ((b::int)) = (uu::int)";
+test "(a*(b*c)) div (d*(b::int)*(x*a)) = (uu::int)";
+*)
+
+(*And the same examples for fields such as rat or real:
+print_depth 22;
+set timing;
+set trace_simp;
+fun test s = (Goal s; by (Asm_simp_tac 1));
+
+test "x*k = k*(y::rat)";
+test "k = k*(y::rat)";
+test "a*(b*c) = (b::rat)";
+test "a*(b*c) = d*(b::rat)*(x*a)";
+
+
+test "(x*k) / (k*(y::rat)) = (uu::rat)";
+test "(k) / (k*(y::rat)) = (uu::rat)";
+test "(a*(b*c)) / ((b::rat)) = (uu::rat)";
+test "(a*(b*c)) / (d*(b::rat)*(x*a)) = (uu::rat)";
+
+(*FIXME: what do we do about this?*)
+test "a*(b*c)/(y*z) = d*(b::rat)*(x*a)/z";
+*)