(* Title:  Test_Z_Transform

   Author: Jan Rocnik

   (c) copyright due to lincense terms.

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*)

theory Inverse_Z_Transform imports PolyEq DiffApp Partial_Fractions begin

axiomatization where 

  rule1: "1 = \<delta>[n]" and

  rule2: "|| z || > 1 ==> z / (z - 1) = u [n]" and

  rule3: "|| z || < 1 ==> z / (z - 1) = -u [-n - 1]" and 

  rule4: "c * (z / (z - \<alpha>)) = c * \<alpha>^^^n * u [n]" and

  rule5: "|| z || < || \<alpha> || ==> z / (z - \<alpha>) = -(\<alpha>^^^n) * u [-n - 1]" and

  rule6: "|| z || > 1 ==> z/(z - 1)^^^2 = n * u [n]" (*and

  rule42: "(a * (z/(z-b)) + c * (z/(z-d))) = (a * b^^^n * u [n] + c * d^^^n * u [n])"*)

axiomatization where

  ruleZY: "(X z = a / b) = (X' z = a / (z * b))" and

  ruleYZ: "(a/b + c/d) = (a*(z/b) + c*(z/d))" 

subsection{*Define the Field Descriptions for the specification*}

consts

  filterExpression  :: "bool => una"

  stepResponse      :: "bool => una"

ML {*

val inverse_z = prep_rls(

  Rls {id = "inverse_z", preconds = [], rew_ord = ("dummy_ord",dummy_ord), 

	  erls = Erls, srls = Erls, calc = [], errpatts = [],

	  rules = 

	   [

    Thm ("rule4",num_str @{thm rule4})

	   ], 

	 scr = EmptyScr}:rls);

*}

text {*store the rule set for math engine*}

ML {*

ruleset' := overwritelthy @{theory} (!ruleset',

  [("inverse_z", inverse_z)

   ]);

*}

subsection{*Define the Specification*}

ML {*

val thy = @{theory};

store_pbt

 (prep_pbt thy "pbl_SP" [] e_pblID

 (["SignalProcessing"], [], e_rls, NONE, []));

store_pbt

 (prep_pbt thy "pbl_SP_Ztrans" [] e_pblID

 (["Z_Transform","SignalProcessing"], [], e_rls, NONE, []));

store_pbt

 (prep_pbt thy "pbl_SP_Ztrans_inv" [] e_pblID

 (["Inverse", "Z_Transform", "SignalProcessing"],

  (*^ capital letter breaks coding standard

    because "inverse" = Const ("Rings.inverse_class.inverse", ..*)

  [("#Given" ,["filterExpression (X_eq::bool)"]),

   ("#Find"  ,["stepResponse (n_eq::bool)"])

  ],

  append_rls "e_rls" e_rls [(*for preds in where_*)], NONE, 

  [["SignalProcessing","Z_Transform","Inverse"]]));

*}

ML {*

  store_pbt

   (prep_pbt thy "pbl_SP_Ztrans_inv" [] e_pblID

   (["Inverse", "Z_Transform", "SignalProcessing"],

    [("#Given" ,["filterExpression X_eq"]),

     ("#Find"  ,["stepResponse n_eq"])

    ],

    append_rls "e_rls" e_rls [(*for preds in where_*)], NONE, 

    [["SignalProcessing","Z_Transform","Inverse"]]));

*}

subsection {*Define Name and Signature for the Method*}

consts

  InverseZTransform :: "[bool, bool] => bool"

    ("((Script InverseZTransform (_ =))// (_))" 9)

subsection {*Setup Parent Nodes in Hierarchy of Method*}

ML {*

store_met

 (prep_met thy "met_SP" [] e_metID

 (["SignalProcessing"], [],

   {rew_ord'="tless_true", rls'= e_rls, calc = [], srls = e_rls, prls = e_rls,

    crls = e_rls, errpats = [], nrls = e_rls}, "empty_script"));

store_met

 (prep_met thy "met_SP_Ztrans" [] e_metID

 (["SignalProcessing", "Z_Transform"], [],

   {rew_ord'="tless_true", rls'= e_rls, calc = [], srls = e_rls, prls = e_rls,

    crls = e_rls, errpats = [], nrls = e_rls}, "empty_script"));

val thy = @{theory}; (*latest version of thy required*)

store_met

 (prep_met thy "met_SP_Ztrans_inv" [] e_metID

 (["SignalProcessing", "Z_Transform", "Inverse"], 

  [("#Given" ,["filterExpression (X_eq::bool)"]),

   ("#Find"  ,["stepResponse (n_eq::bool)"])

  ],

   {rew_ord'="tless_true", rls'= e_rls, calc = [], srls = e_rls, prls = e_rls,

    crls = e_rls, errpats = [], nrls = e_rls},

"Script InverseZTransform (X_eq::bool) =" ^ (*(1/z) instead of z ^^^ -1*)

" (let X = Take X_eq;" ^

"      X' = Rewrite ruleZY False X;" ^ (*z * denominator*)

"      X' = (Rewrite_Set norm_Rational False) X';" ^ (*simplify*)

"      funterm = Take (rhs X');" ^ (*drop X' z = for equation solving*)

"      denom = (Rewrite_Set partial_fraction False) funterm;" ^ (*get_denominator*)

"      equ = (denom = (0::real));" ^

"      fun_arg = Take (lhs X');" ^

"      arg = (Rewrite_Set partial_fraction False) X';" ^ (*get_argument TODO*)

"      (L_L::bool list) =                                    " ^

"            (SubProblem (Test',                            " ^

"                         [linear,univariate,equation,test]," ^

"                         [Test,solve_linear])              " ^

"                        [BOOL equ, REAL z])              " ^

"  in X)"

 ));

*}

ML {*

  store_met(

    prep_met thy "met_SP_Ztrans_inv" [] e_metID

    (["SignalProcessing",

      "Z_Transform",

      "Inverse"], 

     [

       ("#Given" ,["filterExpression X_eq"]),

       ("#Find"  ,["stepResponse n_eq"])

     ],

     {

       rew_ord'="tless_true",

       rls'= e_rls, calc = [],

       srls = srls_partial_fraction, 

       prls = e_rls,

       crls = e_rls, errpats = [], nrls = e_rls

     },

     "Script InverseZTransform (X_eq::bool) =                        "^

     (*(1/z) instead of z ^^^ -1*)

     "(let X = Take X_eq;                                            "^

     "      X' = Rewrite ruleZY False X;                             "^

     (*z * denominator*)

     "      (num_orig::real) = get_numerator (rhs X');               "^

     "      X' = (Rewrite_Set norm_Rational False) X';               "^

     (*simplify*)

     "      (X'_z::real) = lhs X';                                   "^

     "      (zzz::real) = argument_in X'_z;                          "^

     "      (funterm::real) = rhs X';                                "^

     (*drop X' z = for equation solving*)

     "      (denom::real) = get_denominator funterm;                 "^

     (*get_denominator*)

     "      (num::real) = get_numerator funterm;                     "^

     (*get_numerator*)

     "      (equ::bool) = (denom = (0::real));                       "^

     "      (L_L::bool list) = (SubProblem (PolyEq',                 "^

     "         [abcFormula,degree_2,polynomial,univariate,equation], "^

     "         [no_met])                                             "^

     "         [BOOL equ, REAL zzz]);                                "^

     "      (facs::real) = factors_from_solution L_L;                "^

     "      (eql::real) = Take (num_orig / facs);                    "^ 

     "      (eqr::real) = (Try (Rewrite_Set ansatz_rls False)) eql;  "^

     "      (eq::bool) = Take (eql = eqr);                           "^

     (*Maybe possible to use HOLogic.mk_eq ??*)

     "      eq = (Try (Rewrite_Set equival_trans False)) eq;         "^ 

     "      eq = drop_questionmarks eq;                              "^

     "      (z1::real) = (rhs (NTH 1 L_L));                          "^

     (* 

      * prepare equation for a - eq_a

      * therefor substitute z with solution 1 - z1

      *)

     "      (z2::real) = (rhs (NTH 2 L_L));                          "^

     "      (eq_a::bool) = Take eq;                                  "^

     "      eq_a = (Substitute [zzz=z1]) eq;                         "^

     "      eq_a = (Rewrite_Set norm_Rational False) eq_a;           "^

     "      (sol_a::bool list) =                                     "^

     "                 (SubProblem (Isac',                           "^

     "                              [univariate,equation],[no_met])  "^

     "                              [BOOL eq_a, REAL (A::real)]);    "^

     "      (a::real) = (rhs(NTH 1 sol_a));                          "^

     "      (eq_b::bool) = Take eq;                                  "^

     "      eq_b =  (Substitute [zzz=z2]) eq_b;                      "^

     "      eq_b = (Rewrite_Set norm_Rational False) eq_b;           "^

     "      (sol_b::bool list) =                                     "^

     "                 (SubProblem (Isac',                           "^

     "                              [univariate,equation],[no_met])  "^

     "                              [BOOL eq_b, REAL (B::real)]);    "^

     "      (b::real) = (rhs(NTH 1 sol_b));                          "^

     "      eqr = drop_questionmarks eqr;                            "^

     "      (pbz::real) = Take eqr;                                  "^

     "      pbz = ((Substitute [A=a, B=b]) pbz);                     "^

     "      pbz = Rewrite ruleYZ False pbz;                          "^

     "      pbz = drop_questionmarks pbz;                            "^

     "      (X_z::bool) = Take (X_z = pbz);                          "^

     "      (n_eq::bool) = (Rewrite_Set inverse_z False) X_z;        "^

     "      n_eq = drop_questionmarks n_eq                           "^

     "in n_eq)" 

    )

           );

store_met (prep_met thy "met_SP_Ztrans_inv_sub" [] e_metID

  (["SignalProcessing", "Z_Transform", "Inverse_sub"], 

   [("#Given" ,["filterExpression X_eq"]),

    ("#Find"  ,["stepResponse n_eq"])],

   {rew_ord'="tless_true",

    rls'= e_rls, calc = [],

    srls = Rls {id="srls_partial_fraction", 

      preconds = [],

      rew_ord = ("termlessI",termlessI),

      erls = append_rls "erls_in_srls_partial_fraction" e_rls

       [(*for asm in NTH_CONS ...*)

        Calc ("Orderings.ord_class.less",eval_equ "#less_"),

        (*2nd NTH_CONS pushes n+-1 into asms*)

        Calc("Groups.plus_class.plus", eval_binop "#add_")], 

        srls = Erls, calc = [], errpatts = [],

        rules = [

          Thm ("NTH_CONS",num_str @{thm NTH_CONS}),

          Calc("Groups.plus_class.plus", eval_binop "#add_"),

          Thm ("NTH_NIL",num_str @{thm NTH_NIL}),

          Calc("Tools.lhs", eval_lhs "eval_lhs_"),

          Calc("Tools.rhs", eval_rhs"eval_rhs_"),

          Calc("Atools.argument'_in", eval_argument_in "Atools.argument'_in"),

          Calc("Rational.get_denominator", eval_get_denominator "#get_denominator"),

          Calc("Rational.get_numerator", eval_get_numerator "#get_numerator"),

          Calc("Partial_Fractions.factors_from_solution",

            eval_factors_from_solution "#factors_from_solution"),

          Calc("Partial_Fractions.drop_questionmarks", eval_drop_questionmarks "#drop_?")],

          scr = EmptyScr},

    prls = e_rls, crls = e_rls, errpats = [], nrls = norm_Rational},

   "Script InverseZTransform (X_eq::bool) =            "^(*([], Frm), Problem (Isac, [Inverse, Z_Transform, SignalProcessing])*)

   "(let X = Take X_eq;                                "^(*([1], Frm), X z = 3 / (z - 1 / 4 + -1 / 8 * (1 / z))*)

   "  X' = Rewrite ruleZY False X;                     "^(*([1], Res), ?X' z = 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z)))*)

   "  (X'_z::real) = lhs X';                           "^(*            ?X' z*)

   "  (zzz::real) = argument_in X'_z;                  "^(*            z *)

   "  (funterm::real) = rhs X';                        "^(*            3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z)))*)

   "  (pbz::real) = (SubProblem (Isac',                "^(**)

   "    [partial_fraction,rational,simplification],    "^

   "    [simplification,of_rationals,to_partial_fraction]) "^

   "    [REAL funterm, REAL zzz]);                     "^(*([2], Res), 4 / (z - 1 / 2) + -4 / (z - -1 / 4)*)

   "  (pbz_eq::bool) = Take (X'_z = pbz);              "^(*([3], Frm), ?X' z = 4 / (z - 1 / 2) + -4 / (z - -1 / 4)*)

   "  pbz_eq = Rewrite ruleYZ False pbz_eq;            "^(*([3], Res), ?X' z = 4 * (?z / (z - 1 / 2)) + -4 * (?z / (z - -1 / 4))*)

   "  pbz_eq = drop_questionmarks pbz_eq;              "^(*               4 * (z / (z - 1 / 2)) + -4 * (z / (z - -1 / 4))*)

   "  (X_zeq::bool) = Take (X_z = rhs pbz_eq);         "^(*([4], Frm), X_z = 4 * (z / (z - 1 / 2)) + -4 * (z / (z - -1 / 4))*)

   "  n_eq = (Rewrite_Set inverse_z False) X_zeq;      "^(*([4], Res), X_z = 4 * (1 / 2) ^^^ ?n * ?u [?n] + -4 * (-1 / 4) ^^^ ?n * ?u [?n]*)

   "  n_eq = drop_questionmarks n_eq                   "^(*            X_z = 4 * (1 / 2) ^^^ n * u [n] + -4 * (-1 / 4) ^^^ n * u [n]*)

   "in n_eq)"                                            (*([], Res), X_z = 4 * (1 / 2) ^^^ n * u [n] + -4 * (-1 / 4) ^^^ n * u [n]*)

  ));

*}

end