neuper@42376: (* Partial_Fractions 
jan@42344:    author: Jan Rocnik, isac team
jan@42344:    Copyright (c) isac team 2011
jan@42344:    Use is subject to license terms.
jan@42344: *)
wneuper@59344: (* Partial Fraction Decomposition *)
jan@42344: 
neuper@42289: 
neuper@42376: theory Partial_Fractions imports RootRatEq begin
jan@42353: 
wneuper@59472: ML\<open>
neuper@42376: (*
jan@42353: signature PARTFRAC =
jan@42353: sig
jan@42353:   val ansatz_rls : rls
jan@42353:   val ansatz_rls_ : theory -> term -> (term * term list) option
jan@42353: end
neuper@42376: *)
wneuper@59472: \<close>
jan@42353: 
wneuper@59472: subsection \<open>eval_ functions\<close>
jan@42344: consts
neuper@42359:   factors_from_solution :: "bool list => real"
wneuper@59512:   AA                    :: real
wneuper@59512:   BB                    :: real
jan@42344: 
wneuper@59472: text \<open>these might be used for variants of fac_from_sol\<close>
wneuper@59472: ML \<open>
jan@42344: fun mk_minus_1 T = Free("-1", T); (*TODO DELETE WITH numbers_to_string*)
jan@42344: fun flip_sign t = (*TODO improve for use in factors_from_solution: -(-1) etc*)
jan@42344:   let val minus_1 = t |> type_of |> mk_minus_1
wenzelm@60309:   in HOLogic.mk_binop \<^const_name>\<open>times\<close> (minus_1, t) end;
wneuper@59472: \<close>
neuper@42376: 
wneuper@59472: text \<open>from solutions (e.g. [z = 1, z = -2]) make linear factors (e.g. (z - 1)*(z - -2))\<close>
wneuper@59472: ML \<open>
jan@42344: fun fac_from_sol s =
jan@42344:   let val (lhs, rhs) = HOLogic.dest_eq s
wenzelm@60309:   in HOLogic.mk_binop \<^const_name>\<open>minus\<close> (lhs, rhs) end;
jan@42344: 
jan@42344: fun mk_prod prod [] =
walther@59962:       if prod = TermC.empty then raise ERROR "mk_prod called with []" else prod
jan@42344:   | mk_prod prod (t :: []) =
wenzelm@60309:       if prod = TermC.empty then t else HOLogic.mk_binop \<^const_name>\<open>times\<close> (prod, t)
jan@42344:   | mk_prod prod (t1 :: t2 :: ts) =
walther@59861:         if prod = TermC.empty 
jan@42344:         then 
wenzelm@60309:            let val p = HOLogic.mk_binop \<^const_name>\<open>times\<close> (t1, t2)
jan@42344:            in mk_prod p ts end 
jan@42344:         else 
wenzelm@60309:            let val p = HOLogic.mk_binop \<^const_name>\<open>times\<close> (prod, t1)
jan@42344:            in mk_prod p (t2 :: ts) end 
jan@42344: 
jan@42344: fun factors_from_solution sol = 
jan@42344:   let val ts = HOLogic.dest_list sol
walther@59861:   in mk_prod TermC.empty (map fac_from_sol ts) end;
jan@42344: 
neuper@42376: (*("factors_from_solution", ("Partial_Fractions.factors_from_solution", 
walther@60264:      eval_factors_from_solution ""))
walther@60264:   this code is limited (max 3 solutions) AND has too little checks *)
jan@42352: fun eval_factors_from_solution (thmid:string) _
Walther@60504:     (t as Const (\<^const_name>\<open>Partial_Fractions.factors_from_solution\<close>, _) $ sol) ctxt =
walther@60264:       let val prod = factors_from_solution sol
Walther@60504:       in SOME (TermC.mk_thmid thmid (UnparseC.term_in_ctxt ctxt prod) "",
walther@60264:            HOLogic.Trueprop $ (TermC.mk_equality (t, prod)))
walther@60264:       end
walther@60264:   | eval_factors_from_solution _ _ _ _ = NONE;
wneuper@59472: \<close>
jan@42344: 
wneuper@59472: subsection \<open>'ansatz' for partial fractions\<close>
jan@42353: axiomatization where
wneuper@59512:   ansatz_2nd_order: "n / (a*b) = AA/a + BB/b" and
wneuper@59512:   ansatz_3rd_order: "n / (a*b*c) = AA/a + BB/b + C/c" and
wneuper@59512:   ansatz_4th_order: "n / (a*b*c*d) = AA/a + BB/b + C/c + D/d" and
neuper@42386:   (*version 1*)
wneuper@59512:   equival_trans_2nd_order: "(n/(a*b) = AA/a + BB/b) = (n = AA*b + BB*a)" and
wneuper@59512:   equival_trans_3rd_order: "(n/(a*b*c) = AA/a + BB/b + C/c) = (n = AA*b*c + BB*a*c + C*a*b)" and
wneuper@59512:   equival_trans_4th_order: "(n/(a*b*c*d) = AA/a + BB/b + C/c + D/d) = 
wneuper@59512:     (n = AA*b*c*d + BB*a*c*d + C*a*b*d + D*a*b*c)" and
neuper@42386:   (*version 2: not yet used, see partial_fractions.sml*)
wneuper@59512:   multiply_2nd_order: "(n/x = AA/a + BB/b) = (a*b*n/x = AA*b + BB*a)" and
wneuper@59512:   multiply_3rd_order: "(n/x = AA/a + BB/b + C/c) = (a*b*c*n/x = AA*b*c + BB*a*c + C*a*b)" and
neuper@42387:   multiply_4th_order: 
wneuper@59512:     "(n/x = AA/a + BB/b + C/c + D/d) = (a*b*c*d*n/x = AA*b*c*d + BB*a*c*d + C*a*b*d + D*a*b*c)"
neuper@42387: 
wneuper@59472: text \<open>Probably the optimal formalization woudl be ...
neuper@42387: 
wneuper@59512:   multiply_2nd_order: "x = a*b ==> (n/x = AA/a + BB/b) = (a*b*n/x = AA*b + BB*a)" and
neuper@42386:   multiply_3rd_order: "x = a*b*c ==>
wneuper@59512:     (n/x = AA/a + BB/b + C/c) = (a*b*c*n/x = AA*b*c + BB*a*c + C*a*b)" and
neuper@42386:   multiply_4th_order: "x = a*b*c*d ==>
wneuper@59512:     (n/x = AA/a + BB/b + C/c + D/d) = (a*b*c*d*n/x = AA*b*c*d + BB*a*c*d + C*a*b*d + D*a*b*c)"
jan@42353: 
neuper@42387: ... because it would allow to start the ansatz as follows
neuper@42387: (1) 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z))) = 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z)))
neuper@42387: (2) 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z))) = AA / (z - 1 / 2) + BB / (z - -1 / 4)
neuper@42387: (3) (z - 1 / 2) * (z - -1 / 4) * 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z))) = 
neuper@42387:     (z - 1 / 2) * (z - -1 / 4) * AA / (z - 1 / 2) + BB / (z - -1 / 4)
wneuper@59512: (4) 3 = AA * (z - -1 / 4) + BB * (z - 1 / 2)
neuper@42387: 
neuper@42387: ... (1==>2) ansatz
neuper@42387:     (2==>3) multiply_*
neuper@42387:     (3==>4) norm_Rational
wneuper@59550: TODOs for this version are in partial_fractions.sml "--- progr.vers.2: "
wneuper@59472: \<close>
neuper@42387: 
wneuper@59472: ML \<open>
s1210629013@55444: val ansatz_rls = prep_rls'(
Walther@60509:   Rule_Def.Repeat {id = "ansatz_rls", preconds = [], rew_ord = ("dummy_ord",Rewrite_Ord.function_empty), 
walther@59851: 	  erls = Rule_Set.Empty, srls = Rule_Set.Empty, calc = [], errpatts = [],
walther@60358: 	  rules = [
walther@60358:       \<^rule_thm>\<open>ansatz_2nd_order\<close>,
walther@60358: 	    \<^rule_thm>\<open>ansatz_3rd_order\<close>], 
walther@60358: 	  scr = Rule.Empty_Prog});
jan@42353: 
s1210629013@55444: val equival_trans = prep_rls'(
Walther@60509:   Rule_Def.Repeat {id = "equival_trans", preconds = [], rew_ord = ("dummy_ord",Rewrite_Ord.function_empty), 
walther@59851: 	  erls = Rule_Set.Empty, srls = Rule_Set.Empty, calc = [], errpatts = [],
walther@60358: 	  rules = [
walther@60358:       \<^rule_thm>\<open>equival_trans_2nd_order\<close>,
walther@60358: 	    \<^rule_thm>\<open>equival_trans_3rd_order\<close>], 
walther@60358: 	  scr = Rule.Empty_Prog});
neuper@42386: 
s1210629013@55444: val multiply_ansatz = prep_rls'(
Walther@60509:   Rule_Def.Repeat {id = "multiply_ansatz", preconds = [], rew_ord = ("dummy_ord",Rewrite_Ord.function_empty), 
walther@59851: 	  erls = Rule_Set.Empty,
walther@59851: 	  srls = Rule_Set.Empty, calc = [], errpatts = [],
walther@60358: 	  rules = [
walther@60358:       \<^rule_thm>\<open>multiply_2nd_order\<close>], 
walther@60358: 	  scr = Rule.Empty_Prog});
wneuper@59472: \<close>
jan@42354: 
wneuper@59472: text \<open>store the rule set for math engine\<close>
wenzelm@60289: rule_set_knowledge
wenzelm@60286:   ansatz_rls = ansatz_rls and
wenzelm@60286:   multiply_ansatz = multiply_ansatz and
wenzelm@60286:   equival_trans = equival_trans
jan@42344: 
wneuper@59472: subsection \<open>Specification\<close>
jan@42344: 
neuper@42376: consts
neuper@42376:   decomposedFunction :: "real => una"
neuper@42376: 
Walther@60502: declare [[check_unique = false]] (*WN120307 REMOVE after editing*)
Walther@60502: 
wenzelm@60306: problem pbl_simp_rat_partfrac : "partial_fraction/rational/simplification" =
wenzelm@60306:   \<open>Rule_Set.append_rules "empty" Rule_Set.empty [(*for preds in where_ TODO*)]\<close>
Walther@60449:   Method_Ref: "simplification/of_rationals/to_partial_fraction"
wenzelm@60306:   Given: "functionTerm t_t" "solveFor v_v"
wenzelm@60306:   (* TODO: call this sub-problem with appropriate functionTerm: 
wenzelm@60306:     leading coefficient of the denominator is 1: to be checked here! and..
wenzelm@60306:   Where: "((get_numerator t_t) has_degree_in v_v) < 
wenzelm@60306:        ((get_denominator t_t) has_degree_in v_v)" TODO*)
wenzelm@60306:   Find: "decomposedFunction p_p'''"
jan@42354: 
walther@60154: subsection \<open>MethodC\<close>
wneuper@59585: text \<open>rule set for functions called in the Program\<close>
wneuper@59472: ML \<open>
walther@60358: val srls_partial_fraction = Rule_Def.Repeat {id="srls_partial_fraction", 
walther@60358:   preconds = [],
walther@60358:   rew_ord = ("termlessI",termlessI),
walther@60358:   erls = Rule_Set.append_rules "erls_in_srls_partial_fraction" Rule_Set.empty
walther@60358:     [(*for asm in NTH_CONS ...*)
walther@60358:      \<^rule_eval>\<open>less\<close> (Prog_Expr.eval_equ "#less_"),
walther@60358:      (*2nd NTH_CONS pushes n+-1 into asms*)
walther@60358:      \<^rule_eval>\<open>plus\<close> (**)(eval_binop "#add_")], 
walther@60358:   srls = Rule_Set.Empty, calc = [], errpatts = [],
walther@60358:   rules = [
walther@60358:      \<^rule_thm>\<open>NTH_CONS\<close>,
walther@60358:      \<^rule_eval>\<open>plus\<close> (**)(eval_binop "#add_"),
walther@60358:      \<^rule_thm>\<open>NTH_NIL\<close>,
walther@60358:      \<^rule_eval>\<open>Prog_Expr.lhs\<close> (Prog_Expr.eval_lhs "eval_lhs_"),
walther@60358:      \<^rule_eval>\<open>Prog_Expr.rhs\<close> (Prog_Expr.eval_rhs"eval_rhs_"),
walther@60358:      \<^rule_eval>\<open>Prog_Expr.argument_in\<close> (Prog_Expr.eval_argument_in "Prog_Expr.argument_in"),
walther@60358:      \<^rule_eval>\<open>get_denominator\<close> (eval_get_denominator "#get_denominator"),
walther@60358:      \<^rule_eval>\<open>get_numerator\<close> (eval_get_numerator "#get_numerator"),
walther@60358:      \<^rule_eval>\<open>factors_from_solution\<close> (eval_factors_from_solution "#factors_from_solution")],
walther@60358:   scr = Rule.Empty_Prog};
wneuper@59472: \<close>
neuper@42415: 
s1210629013@55380: (* current version, error outcommented *)
wneuper@59504: partial_function (tailrec) partial_fraction :: "real \<Rightarrow> real \<Rightarrow> real"
wneuper@59504:   where
wneuper@59504: "partial_fraction f_f zzz =              \<comment> \<open>([1], Frm), 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z)))\<close>
wneuper@59504: (let f_f = Take f_f;                                                             \<comment> \<open>num_orig = 3\<close>
walther@60260:   num_orig = get_numerator f_f;                  \<comment> \<open>([1], Res), 24 / (-1 + -2 * z + 8 * z  \<up>  2)\<close>
walther@60260:   f_f = (Rewrite_Set ''norm_Rational'') f_f;                \<comment> \<open>denom = -1 + -2 * z + 8 * z  \<up>  2\<close>
walther@60260:   denom = get_denominator f_f;                            \<comment> \<open>equ = -1 + -2 * z + 8 * z  \<up>  2 = 0\<close>
wneuper@59504:   equ = denom = (0::real);
walther@60260:   \<comment> \<open>-----                                  ([2], Pbl), solve (-1 + -2 * z + 8 * z  \<up>  2 = 0, z)\<close>
wneuper@59513:   L_L = SubProblem (''Partial_Fractions'',                 \<comment> \<open>([2], Res), [z = 1 / 2, z = -1 / 4\<close>
wneuper@59504:     [''abcFormula'', ''degree_2'', ''polynomial'', ''univariate'', ''equation''],
wneuper@59504:     [''no_met'']) [BOOL equ, REAL zzz];                      \<comment> \<open>facs: (z - 1 / 2) * (z - -1 / 4)\<close>
wneuper@59504:   facs = factors_from_solution L_L;             \<comment> \<open>([3], Frm), 33 / ((z - 1 / 2) * (z - -1 / 4))\<close>
wneuper@59504:   eql = Take (num_orig / facs);              \<comment> \<open>([3], Res), ?A / (z - 1 / 2) + ?B / (z - -1 / 4)\<close>
walther@59635:   eqr = (Try (Rewrite_Set ''ansatz_rls'')) eql;
wneuper@59504:           \<comment> \<open>([4], Frm), 3 / ((z - 1 / 2) * (z - -1 / 4)) = ?A / (z - 1 / 2) + ?B / (z - -1 / 4)\<close>
wneuper@59536:   eq = Take (eql = eqr);                 \<comment> \<open>([4], Res), 3 = ?A * (z - -1 / 4) + ?B * (z - 1 / 2)\<close>
walther@59635:   eq = (Try (Rewrite_Set ''equival_trans'')) eq; 
wneuper@59536:                                                 \<comment> \<open>eq = 3 = AA * (z - -1 / 4) + BB * (z - 1 / 2)\<close>
wneuper@59504:   z1 = rhs (NTH 1 L_L);                                                           \<comment> \<open>z2 = -1 / 4\<close>
wneuper@59536:   z2 = rhs (NTH 2 L_L);                  \<comment> \<open>([5], Frm), 3 = AA * (z - -1 / 4) + BB * (z - 1 / 2)\<close>
wneuper@59536:   eq_a = Take eq;                \<comment> \<open>([5], Res), 3 = AA * (1 / 2 - -1 / 4) + BB * (1 / 2 - 1 / 2)\<close>
wneuper@59536:   eq_a = Substitute [zzz = z1] eq;                                 \<comment> \<open>([6], Res), 3 = 3 * AA / 4\<close>
walther@59635:   eq_a = (Rewrite_Set ''norm_Rational'') eq_a;
wneuper@59536: \<comment> \<open>-----                                                  ([7], Pbl), solve (3 = 3 * AA / 4, AA)\<close>
wneuper@59536:                                                                          \<comment> \<open>([7], Res), [AA = 4]\<close>
wneuper@59592:   sol_a = SubProblem (''Isac_Knowledge'', [''univariate'',''equation''], [''no_met''])
wneuper@59536:       [BOOL eq_a, REAL (AA::real)] ;                                                    \<comment> \<open>a = 4\<close>
wneuper@59536:   a = rhs (NTH 1 sol_a);                 \<comment> \<open>([8], Frm), 3 = AA * (z - -1 / 4) + BB * (z - 1 / 2)\<close>
wneuper@59536:   eq_b = Take eq;              \<comment> \<open>([8], Res), 3 = AA * (-1 / 4 - -1 / 4) + BB * (-1 / 4 - 1 / 2)\<close>
wneuper@59536:   eq_b = Substitute [zzz = z2] eq_b;                              \<comment> \<open>([9], Res), 3 = -3 * BB / 4\<close>
walther@59635:   eq_b = (Rewrite_Set ''norm_Rational'') eq_b;       \<comment> \<open>([10], Pbl), solve (3 = -3 * BB / 4, BB)\<close>
walther@59635:   sol_b = SubProblem (''Isac_Knowledge'',                              \<comment> \<open>([10], Res), [BB = -4]\<close>
wneuper@59504:       [''univariate'',''equation''], [''no_met''])
wneuper@59536:     [BOOL eq_b, REAL (BB::real)];                                                      \<comment> \<open>b = -4\<close>
wneuper@59536:   b = rhs (NTH 1 sol_b);                           \<comment> \<open>eqr = AA / (z - 1 / 2) + BB / (z - -1 / 4)\<close>
wneuper@59504:   pbz = Take eqr;                            \<comment> \<open>([11], Res), 4 / (z - 1 / 2) + -4 / (z - -1 / 4)\<close>
wneuper@59512:   pbz = Substitute [AA = a, BB = b] pbz        \<comment> \<open>([], Res), 4 / (z - 1 / 2) + -4 / (z - -1 / 4)\<close>
wneuper@59504: in pbz)                                                                                "
wenzelm@60303: 
wenzelm@60303: method met_partial_fraction : "simplification/of_rationals/to_partial_fraction" =
wenzelm@60303:   \<open>{rew_ord'="tless_true", rls'= Rule_Set.empty, calc = [], srls = srls_partial_fraction, prls = Rule_Set.empty,
wenzelm@60303:    crls = Rule_Set.empty, errpats = [], nrls = Rule_Set.empty}\<close>
wenzelm@60303:     (*f_f = 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z)), zzz: z*)
wenzelm@60303:     (*([], Frm), Problem (Partial_Fractions, [partial_fraction, rational, simplification])*)
wenzelm@60303:   Program: partial_fraction.simps
wenzelm@60303:   Given: "functionTerm t_t" "solveFor v_v"
wenzelm@60303:   (* Where: "((get_numerator t_t) has_degree_in v_v) <
wenzelm@60303:     ((get_denominator t_t) has_degree_in v_v)" TODO *)
wenzelm@60303:   Find: "decomposedFunction p_p'''"
wenzelm@60303: 
wneuper@59472: ML \<open>
neuper@42376: (*
neuper@42376:   val fmz =                                             
neuper@42376:     ["functionTerm (3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z))))", 
neuper@42376:       "solveFor z", "functionTerm p_p"];
neuper@42376:   val (dI',pI',mI') =
neuper@42376:     ("Partial_Fractions", 
neuper@42376:       ["partial_fraction", "rational", "simplification"],
walther@59997:       ["simplification", "of_rationals", "to_partial_fraction"]);
neuper@42376:   val (p,_,f,nxt,_,pt) = CalcTreeTEST [(fmz, (dI',pI',mI'))];
neuper@42376: *)
walther@60278: \<close>ML \<open>
walther@60278: \<close> ML \<open>
wneuper@59472: \<close>
neuper@42289: end