1 (* Title: Inverse_Z_Transform
3 (c) copyright due to lincense terms.
6 theory Inverse_Z_Transform imports PolyEq DiffApp Partial_Fractions begin
8 axiomatization where \<comment> \<open>TODO: new variables on the rhs enforce replacement by substitution\<close>
9 rule1: "1 = \<delta>[n]" and
10 rule2: "|| z || > 1 ==> z / (z - 1) = u [n]" and
11 rule3: "|| z || < 1 ==> z / (z - 1) = -u [-n - 1]" and
12 rule4: "c * (z / (z - \<alpha>)) = c * \<alpha> \<up> n * u [n]" and
13 rule5: "|| z || < || \<alpha> || ==> z / (z - \<alpha>) = -(\<alpha> \<up> n) * u [-n - 1]" and
14 rule6: "|| z || > 1 ==> z/(z - 1) \<up> 2 = n * u [n]" (*and
15 rule42: "(a * (z/(z-b)) + c * (z/(z-d))) = (a * b \<up> n * u [n] + c * d \<up> n * u [n])"*)
18 (*ruleZY: "(X z = a / b) = (d_d z X = a / (z * b))" ..looks better, but types are flawed*)
19 ruleZY: "(X z = a / b) = (X' z = a / (z * b))" and
20 ruleYZ: "a / (z - b) + c / (z - d) = a * (z / (z - b)) + c * (z / (z - d))" and
21 ruleYZa: "(a / b + c / d) = (a * (z / b) + c * (z / d))" \<comment> \<open>that is what students learn\<close>
23 subsection\<open>Define the Field Descriptions for the specification\<close>
25 filterExpression :: "bool => una"
26 stepResponse :: "bool => una" \<comment> \<open>TODO: unused, "u [n]" is introduced by rule1..6 above\<close>
29 val inverse_z = prep_rls'(
30 Rule_Def.Repeat {id = "inverse_z", preconds = [], rew_ord = ("dummy_ord",Rewrite_Ord.dummy_ord),
31 erls = Rule_Set.Empty, srls = Rule_Set.Empty, calc = [], errpatts = [],
34 \<^rule_thm>\<open>rule4\<close>
36 scr = Rule.Empty_Prog});
40 text \<open>store the rule set for math engine\<close>
42 rule_set_knowledge inverse_z = inverse_z
44 subsection\<open>Define the Specification\<close>
46 setup \<open>KEStore_Elems.add_pbts
47 [(Problem.prep_input @{theory} "pbl_SP" [] Problem.id_empty (["SignalProcessing"], [], Rule_Set.empty, NONE, [])),
48 (Problem.prep_input @{theory} "pbl_SP_Ztrans" [] Problem.id_empty
49 (["Z_Transform", "SignalProcessing"], [], Rule_Set.empty, NONE, [])),
50 (Problem.prep_input @{theory} "pbl_SP_Ztrans_inv" [] Problem.id_empty
51 (["Inverse", "Z_Transform", "SignalProcessing"],
52 [("#Given" , ["filterExpression X_eq"]),
53 ("#Find" ,["stepResponse n_eq"])], \<comment> \<open>TODO: unused, "u [n]" is introduced by rule1..6\<close>
54 Rule_Set.append_rules "empty" Rule_Set.empty [(*for preds in where_*)], NONE,
55 [["SignalProcessing", "Z_Transform", "Inverse"]]))]\<close>
57 subsection \<open>Setup Parent Nodes in Hierarchy of MethodC\<close>
59 setup \<open>KEStore_Elems.add_mets
60 [MethodC.prep_input @{theory} "met_SP" [] MethodC.id_empty
61 (["SignalProcessing"], [],
62 {rew_ord'="tless_true", rls'= Rule_Set.empty, calc = [], srls = Rule_Set.empty, prls = Rule_Set.empty, crls = Rule_Set.empty,
63 errpats = [], nrls = Rule_Set.empty}, @{thm refl}),
64 MethodC.prep_input @{theory} "met_SP_Ztrans" [] MethodC.id_empty
65 (["SignalProcessing", "Z_Transform"], [],
66 {rew_ord'="tless_true", rls'= Rule_Set.empty, calc = [], srls = Rule_Set.empty, prls = Rule_Set.empty, crls = Rule_Set.empty,
67 errpats = [], nrls = Rule_Set.empty}, @{thm refl})]
70 partial_function (tailrec) inverse_ztransform :: "bool \<Rightarrow> real \<Rightarrow> bool"
72 "inverse_ztransform X_eq X_z = (
75 X' = Rewrite ''ruleZY'' X; \<comment> \<open>z * denominator\<close>
76 X' = (Rewrite_Set ''norm_Rational'' ) X'; \<comment> \<open>simplify\<close>
77 funterm = Take (rhs X'); \<comment> \<open>drop X' z = for equation solving\<close>
78 denom = (Rewrite_Set ''partial_fraction'' ) funterm; \<comment> \<open>get_denominator\<close>
79 equ = (denom = (0::real));
80 fun_arg = Take (lhs X');
81 arg = (Rewrite_Set ''partial_fraction'' ) X'; \<comment> \<open>get_argument TODO\<close>
82 (L_L::bool list) = \<comment> \<open>'bool list' inhibits:
83 WARNING: Additional type variable(s) in specification of inverse_ztransform: 'a\<close>
84 SubProblem (''Test'', [''LINEAR'',''univariate'',''equation'',''test''], [''Test'',''solve_linear''])
87 setup \<open>KEStore_Elems.add_mets
88 [MethodC.prep_input @{theory} "met_SP_Ztrans_inv" [] MethodC.id_empty
89 (["SignalProcessing", "Z_Transform", "Inverse"],
90 [("#Given" ,["filterExpression X_eq", "functionName X_z"]),
91 ("#Find" ,["stepResponse n_eq"])], \<comment> \<open>TODO: unused, "u [n]" is introduced by rule1..6\<close>
92 {rew_ord'="tless_true", rls'= Rule_Set.empty, calc = [], srls = Rule_Set.empty, prls = Rule_Set.empty, crls = Rule_Set.empty,
93 errpats = [], nrls = Rule_Set.empty},
94 @{thm inverse_ztransform.simps})]
97 partial_function (tailrec) inverse_ztransform2 :: "bool \<Rightarrow> real \<Rightarrow> bool"
99 "inverse_ztransform2 X_eq X_z = (
102 X' = Rewrite ''ruleZY'' X;
104 zzz = argument_in X_z;
106 pbz = SubProblem (''Isac_Knowledge'',
107 [''partial_fraction'',''rational'',''simplification''],
108 [''simplification'',''of_rationals'',''to_partial_fraction''])
109 [REAL funterm, REAL zzz];
110 pbz_eq = Take (X_z = pbz);
111 pbz_eq = Rewrite ''ruleYZ'' pbz_eq;
112 X_zeq = Take (X_z = rhs pbz_eq);
113 n_eq = (Rewrite_Set ''inverse_z'' ) X_zeq
115 setup \<open>KEStore_Elems.add_mets
116 [MethodC.prep_input @{theory} "met_SP_Ztrans_inv_sub" [] MethodC.id_empty
117 (["SignalProcessing", "Z_Transform", "Inverse_sub"],
118 [("#Given" ,["filterExpression X_eq", "functionName X_z"]),
119 ("#Find" ,["stepResponse n_eq"])], \<comment> \<open>TODO: unused, "u [n]" is introduced by rule1..6\<close>
120 {rew_ord'="tless_true", rls'= Rule_Set.empty, calc = [],
121 srls = Rule_Def.Repeat {id="srls_partial_fraction",
122 preconds = [], rew_ord = ("termlessI",termlessI),
123 erls = Rule_Set.append_rules "erls_in_srls_partial_fraction" Rule_Set.empty
124 [(*for asm in NTH_CONS ...*)
125 \<^rule_eval>\<open>less\<close> (Prog_Expr.eval_equ "#less_"),
126 (*2nd NTH_CONS pushes n+-1 into asms*)
127 \<^rule_eval>\<open>plus\<close> (**)(eval_binop "#add_")],
128 srls = Rule_Set.Empty, calc = [], errpatts = [],
129 rules = [\<^rule_thm>\<open>NTH_CONS\<close>,
130 \<^rule_eval>\<open>plus\<close> (**)(eval_binop "#add_"),
131 \<^rule_thm>\<open>NTH_NIL\<close>,
132 \<^rule_eval>\<open>Prog_Expr.lhs\<close> (Prog_Expr.eval_lhs "eval_lhs_"),
133 \<^rule_eval>\<open>Prog_Expr.rhs\<close> (Prog_Expr.eval_rhs"eval_rhs_"),
134 \<^rule_eval>\<open>Prog_Expr.argument_in\<close> (Prog_Expr.eval_argument_in "Prog_Expr.argument_in"),
135 \<^rule_eval>\<open>get_denominator\<close> (eval_get_denominator "#get_denominator"),
136 \<^rule_eval>\<open>get_numerator\<close> (eval_get_numerator "#get_numerator"),
137 \<^rule_eval>\<open>factors_from_solution\<close> (eval_factors_from_solution "#factors_from_solution")
138 ], scr = Rule.Empty_Prog},
139 prls = Rule_Set.empty, crls = Rule_Set.empty, errpats = [], nrls = norm_Rational},
140 @{thm inverse_ztransform2.simps})]