src/HOL/Tools/ComputeNumeral.thy
changeset 23664 9c486517354a
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     1 theory ComputeNumeral
       
     2 imports ComputeHOL Float
       
     3 begin
       
     4 
       
     5 (* normalization of bit strings *)
       
     6 lemmas bitnorm = Pls_0_eq Min_1_eq
       
     7 
       
     8 (* neg for bit strings *)
       
     9 lemma neg1: "neg Numeral.Pls = False" by (simp add: Numeral.Pls_def)
       
    10 lemma neg2: "neg Numeral.Min = True" apply (subst Numeral.Min_def) by auto
       
    11 lemma neg3: "neg (x BIT Numeral.B0) = neg x" apply (simp add: neg_def) apply (subst Bit_def) by auto
       
    12 lemma neg4: "neg (x BIT Numeral.B1) = neg x" apply (simp add: neg_def) apply (subst Bit_def) by auto  
       
    13 lemmas bitneg = neg1 neg2 neg3 neg4
       
    14 
       
    15 (* iszero for bit strings *)
       
    16 lemma iszero1: "iszero Numeral.Pls = True" by (simp add: Numeral.Pls_def iszero_def)
       
    17 lemma iszero2: "iszero Numeral.Min = False" apply (subst Numeral.Min_def) apply (subst iszero_def) by simp
       
    18 lemma iszero3: "iszero (x BIT Numeral.B0) = iszero x" apply (subst Numeral.Bit_def) apply (subst iszero_def)+ by auto
       
    19 lemma iszero4: "iszero (x BIT Numeral.B1) = False" apply (subst Numeral.Bit_def) apply (subst iszero_def)+  apply simp by arith
       
    20 lemmas bitiszero = iszero1 iszero2 iszero3 iszero4
       
    21 
       
    22 (* lezero for bit strings *)
       
    23 constdefs
       
    24   "lezero x == (x \<le> 0)"
       
    25 lemma lezero1: "lezero Numeral.Pls = True" unfolding Numeral.Pls_def lezero_def by auto
       
    26 lemma lezero2: "lezero Numeral.Min = True" unfolding Numeral.Min_def lezero_def by auto
       
    27 lemma lezero3: "lezero (x BIT Numeral.B0) = lezero x" unfolding Numeral.Bit_def lezero_def by auto
       
    28 lemma lezero4: "lezero (x BIT Numeral.B1) = neg x" unfolding Numeral.Bit_def lezero_def neg_def by auto
       
    29 lemmas bitlezero = lezero1 lezero2 lezero3 lezero4
       
    30 
       
    31 (* equality for bit strings *)
       
    32 lemma biteq1: "(Numeral.Pls = Numeral.Pls) = True" by auto
       
    33 lemma biteq2: "(Numeral.Min = Numeral.Min) = True" by auto
       
    34 lemma biteq3: "(Numeral.Pls = Numeral.Min) = False" unfolding Pls_def Min_def by auto
       
    35 lemma biteq4: "(Numeral.Min = Numeral.Pls) = False" unfolding Pls_def Min_def by auto
       
    36 lemma biteq5: "(x BIT Numeral.B0 = y BIT Numeral.B0) = (x = y)" unfolding Bit_def by auto
       
    37 lemma biteq6: "(x BIT Numeral.B1 = y BIT Numeral.B1) = (x = y)" unfolding Bit_def by auto
       
    38 lemma biteq7: "(x BIT Numeral.B0 = y BIT Numeral.B1) = False" unfolding Bit_def by (simp, arith) 
       
    39 lemma biteq8: "(x BIT Numeral.B1 = y BIT Numeral.B0) = False" unfolding Bit_def by (simp, arith)
       
    40 lemma biteq9: "(Numeral.Pls = x BIT Numeral.B0) = (Numeral.Pls = x)" unfolding Bit_def Pls_def by auto
       
    41 lemma biteq10: "(Numeral.Pls = x BIT Numeral.B1) = False" unfolding Bit_def Pls_def by (simp, arith) 
       
    42 lemma biteq11: "(Numeral.Min = x BIT Numeral.B0) = False" unfolding Bit_def Min_def by (simp, arith)
       
    43 lemma biteq12: "(Numeral.Min = x BIT Numeral.B1) = (Numeral.Min = x)" unfolding Bit_def Min_def by auto
       
    44 lemma biteq13: "(x BIT Numeral.B0 = Numeral.Pls) = (x = Numeral.Pls)" unfolding Bit_def Pls_def by auto
       
    45 lemma biteq14: "(x BIT Numeral.B1 = Numeral.Pls) = False" unfolding Bit_def Pls_def by (simp, arith)
       
    46 lemma biteq15: "(x BIT Numeral.B0 = Numeral.Min) = False" unfolding Bit_def Pls_def Min_def by (simp, arith)
       
    47 lemma biteq16: "(x BIT Numeral.B1 = Numeral.Min) = (x = Numeral.Min)" unfolding Bit_def Min_def by (simp, arith)
       
    48 lemmas biteq = biteq1 biteq2 biteq3 biteq4 biteq5 biteq6 biteq7 biteq8 biteq9 biteq10 biteq11 biteq12 biteq13 biteq14 biteq15 biteq16
       
    49 
       
    50 (* x < y for bit strings *)
       
    51 lemma bitless1: "(Numeral.Pls < Numeral.Min) = False" unfolding Pls_def Min_def by auto
       
    52 lemma bitless2: "(Numeral.Pls < Numeral.Pls) = False" by auto
       
    53 lemma bitless3: "(Numeral.Min < Numeral.Pls) = True" unfolding Pls_def Min_def by auto
       
    54 lemma bitless4: "(Numeral.Min < Numeral.Min) = False" unfolding Pls_def Min_def by auto
       
    55 lemma bitless5: "(x BIT Numeral.B0 < y BIT Numeral.B0) = (x < y)" unfolding Bit_def by auto
       
    56 lemma bitless6: "(x BIT Numeral.B1 < y BIT Numeral.B1) = (x < y)" unfolding Bit_def by auto
       
    57 lemma bitless7: "(x BIT Numeral.B0 < y BIT Numeral.B1) = (x \<le> y)" unfolding Bit_def by auto
       
    58 lemma bitless8: "(x BIT Numeral.B1 < y BIT Numeral.B0) = (x < y)" unfolding Bit_def by auto
       
    59 lemma bitless9: "(Numeral.Pls < x BIT Numeral.B0) = (Numeral.Pls < x)" unfolding Bit_def Pls_def by auto
       
    60 lemma bitless10: "(Numeral.Pls < x BIT Numeral.B1) = (Numeral.Pls \<le> x)" unfolding Bit_def Pls_def by auto
       
    61 lemma bitless11: "(Numeral.Min < x BIT Numeral.B0) = (Numeral.Pls \<le> x)" unfolding Bit_def Pls_def Min_def by auto
       
    62 lemma bitless12: "(Numeral.Min < x BIT Numeral.B1) = (Numeral.Min < x)" unfolding Bit_def Min_def by auto
       
    63 lemma bitless13: "(x BIT Numeral.B0 < Numeral.Pls) = (x < Numeral.Pls)" unfolding Bit_def Pls_def by auto
       
    64 lemma bitless14: "(x BIT Numeral.B1 < Numeral.Pls) = (x < Numeral.Pls)" unfolding Bit_def Pls_def by auto
       
    65 lemma bitless15: "(x BIT Numeral.B0 < Numeral.Min) = (x < Numeral.Pls)" unfolding Bit_def Pls_def Min_def by auto
       
    66 lemma bitless16: "(x BIT Numeral.B1 < Numeral.Min) = (x < Numeral.Min)" unfolding Bit_def Min_def by auto
       
    67 lemmas bitless = bitless1 bitless2 bitless3 bitless4 bitless5 bitless6 bitless7 bitless8 
       
    68                  bitless9 bitless10 bitless11 bitless12 bitless13 bitless14 bitless15 bitless16
       
    69 
       
    70 (* x \<le> y for bit strings *)
       
    71 lemma bitle1: "(Numeral.Pls \<le> Numeral.Min) = False" unfolding Pls_def Min_def by auto
       
    72 lemma bitle2: "(Numeral.Pls \<le> Numeral.Pls) = True" by auto
       
    73 lemma bitle3: "(Numeral.Min \<le> Numeral.Pls) = True" unfolding Pls_def Min_def by auto
       
    74 lemma bitle4: "(Numeral.Min \<le> Numeral.Min) = True" unfolding Pls_def Min_def by auto
       
    75 lemma bitle5: "(x BIT Numeral.B0 \<le> y BIT Numeral.B0) = (x \<le> y)" unfolding Bit_def by auto
       
    76 lemma bitle6: "(x BIT Numeral.B1 \<le> y BIT Numeral.B1) = (x \<le> y)" unfolding Bit_def by auto
       
    77 lemma bitle7: "(x BIT Numeral.B0 \<le> y BIT Numeral.B1) = (x \<le> y)" unfolding Bit_def by auto
       
    78 lemma bitle8: "(x BIT Numeral.B1 \<le> y BIT Numeral.B0) = (x < y)" unfolding Bit_def by auto
       
    79 lemma bitle9: "(Numeral.Pls \<le> x BIT Numeral.B0) = (Numeral.Pls \<le> x)" unfolding Bit_def Pls_def by auto
       
    80 lemma bitle10: "(Numeral.Pls \<le> x BIT Numeral.B1) = (Numeral.Pls \<le> x)" unfolding Bit_def Pls_def by auto
       
    81 lemma bitle11: "(Numeral.Min \<le> x BIT Numeral.B0) = (Numeral.Pls \<le> x)" unfolding Bit_def Pls_def Min_def by auto
       
    82 lemma bitle12: "(Numeral.Min \<le> x BIT Numeral.B1) = (Numeral.Min \<le> x)" unfolding Bit_def Min_def by auto
       
    83 lemma bitle13: "(x BIT Numeral.B0 \<le> Numeral.Pls) = (x \<le> Numeral.Pls)" unfolding Bit_def Pls_def by auto
       
    84 lemma bitle14: "(x BIT Numeral.B1 \<le> Numeral.Pls) = (x < Numeral.Pls)" unfolding Bit_def Pls_def by auto
       
    85 lemma bitle15: "(x BIT Numeral.B0 \<le> Numeral.Min) = (x < Numeral.Pls)" unfolding Bit_def Pls_def Min_def by auto
       
    86 lemma bitle16: "(x BIT Numeral.B1 \<le> Numeral.Min) = (x \<le> Numeral.Min)" unfolding Bit_def Min_def by auto
       
    87 lemmas bitle = bitle1 bitle2 bitle3 bitle4 bitle5 bitle6 bitle7 bitle8 
       
    88                  bitle9 bitle10 bitle11 bitle12 bitle13 bitle14 bitle15 bitle16
       
    89 
       
    90 (* succ for bit strings *)
       
    91 lemmas bitsucc = succ_Pls succ_Min succ_1 succ_0
       
    92 
       
    93 (* pred for bit strings *)
       
    94 lemmas bitpred = pred_Pls pred_Min pred_1 pred_0
       
    95 
       
    96 (* unary minus for bit strings *)
       
    97 lemmas bituminus = minus_Pls minus_Min minus_1 minus_0 
       
    98 
       
    99 (* addition for bit strings *)
       
   100 lemmas bitadd = add_Pls add_Pls_right add_Min add_Min_right add_BIT_11 add_BIT_10 add_BIT_0[where b="Numeral.B0"] add_BIT_0[where b="Numeral.B1"]
       
   101 
       
   102 (* multiplication for bit strings *) 
       
   103 lemma mult_Pls_right: "x * Numeral.Pls = Numeral.Pls" by (simp add: Pls_def)
       
   104 lemma mult_Min_right: "x * Numeral.Min = - x" by (subst mult_commute, simp add: mult_Min)
       
   105 lemma multb0x: "(x BIT Numeral.B0) * y = (x * y) BIT Numeral.B0" unfolding Bit_def by simp
       
   106 lemma multxb0: "x * (y BIT Numeral.B0) = (x * y) BIT Numeral.B0" unfolding Bit_def by simp
       
   107 lemma multb1: "(x BIT Numeral.B1) * (y BIT Numeral.B1) = (((x * y) BIT Numeral.B0) + x + y) BIT Numeral.B1"
       
   108   unfolding Bit_def by (simp add: ring_simps)
       
   109 lemmas bitmul = mult_Pls mult_Min mult_Pls_right mult_Min_right multb0x multxb0 multb1
       
   110 
       
   111 lemmas bitarith = bitnorm bitiszero bitneg bitlezero biteq bitless bitle bitsucc bitpred bituminus bitadd bitmul 
       
   112 
       
   113 constdefs 
       
   114   "nat_norm_number_of (x::nat) == x"
       
   115 
       
   116 lemma nat_norm_number_of: "nat_norm_number_of (number_of w) = (if lezero w then 0 else number_of w)"
       
   117   apply (simp add: nat_norm_number_of_def)
       
   118   unfolding lezero_def iszero_def neg_def
       
   119   apply (simp add: number_of_is_id)
       
   120   done
       
   121 
       
   122 (* Normalization of nat literals *)
       
   123 lemma natnorm0: "(0::nat) = number_of (Numeral.Pls)" by auto
       
   124 lemma natnorm1: "(1 :: nat) = number_of (Numeral.Pls BIT Numeral.B1)"  by auto 
       
   125 lemmas natnorm = natnorm0 natnorm1 nat_norm_number_of
       
   126 
       
   127 (* Suc *)
       
   128 lemma natsuc: "Suc (number_of x) = (if neg x then 1 else number_of (Numeral.succ x))" by (auto simp add: number_of_is_id)
       
   129 
       
   130 (* Addition for nat *)
       
   131 lemma natadd: "number_of x + ((number_of y)::nat) = (if neg x then (number_of y) else (if neg y then number_of x else (number_of (x + y))))"
       
   132   by (auto simp add: number_of_is_id)
       
   133 
       
   134 (* Subtraction for nat *)
       
   135 lemma natsub: "(number_of x) - ((number_of y)::nat) = 
       
   136   (if neg x then 0 else (if neg y then number_of x else (nat_norm_number_of (number_of (x + (- y))))))"
       
   137   unfolding nat_norm_number_of
       
   138   by (auto simp add: number_of_is_id neg_def lezero_def iszero_def Let_def nat_number_of_def)
       
   139 
       
   140 (* Multiplication for nat *)
       
   141 lemma natmul: "(number_of x) * ((number_of y)::nat) = 
       
   142   (if neg x then 0 else (if neg y then 0 else number_of (x * y)))"
       
   143   apply (auto simp add: number_of_is_id neg_def iszero_def)
       
   144   apply (case_tac "x > 0")
       
   145   apply auto
       
   146   apply (simp add: mult_strict_left_mono[where a=y and b=0 and c=x, simplified])
       
   147   done
       
   148 
       
   149 lemma nateq: "(((number_of x)::nat) = (number_of y)) = ((lezero x \<and> lezero y) \<or> (x = y))"
       
   150   by (auto simp add: iszero_def lezero_def neg_def number_of_is_id)
       
   151 
       
   152 lemma natless: "(((number_of x)::nat) < (number_of y)) = ((x < y) \<and> (\<not> (lezero y)))"
       
   153   by (auto simp add: number_of_is_id neg_def lezero_def)
       
   154 
       
   155 lemma natle: "(((number_of x)::nat) \<le> (number_of y)) = (y < x \<longrightarrow> lezero x)"
       
   156   by (auto simp add: number_of_is_id lezero_def nat_number_of_def)
       
   157 
       
   158 fun natfac :: "nat \<Rightarrow> nat"
       
   159 where
       
   160    "natfac n = (if n = 0 then 1 else n * (natfac (n - 1)))"
       
   161 
       
   162 lemmas compute_natarith = bitarith natnorm natsuc natadd natsub natmul nateq natless natle natfac.simps
       
   163 
       
   164 lemma number_eq: "(((number_of x)::'a::{number_ring, ordered_idom}) = (number_of y)) = (x = y)"
       
   165   unfolding number_of_eq
       
   166   apply simp
       
   167   done
       
   168 
       
   169 lemma number_le: "(((number_of x)::'a::{number_ring, ordered_idom}) \<le>  (number_of y)) = (x \<le> y)"
       
   170   unfolding number_of_eq
       
   171   apply simp
       
   172   done
       
   173 
       
   174 lemma number_less: "(((number_of x)::'a::{number_ring, ordered_idom}) <  (number_of y)) = (x < y)"
       
   175   unfolding number_of_eq 
       
   176   apply simp
       
   177   done
       
   178 
       
   179 lemma number_diff: "((number_of x)::'a::{number_ring, ordered_idom}) - number_of y = number_of (x + (- y))"
       
   180   apply (subst diff_number_of_eq)
       
   181   apply simp
       
   182   done
       
   183 
       
   184 lemmas number_norm = number_of_Pls[symmetric] numeral_1_eq_1[symmetric]
       
   185 
       
   186 lemmas compute_numberarith = number_of_minus[symmetric] number_of_add[symmetric] number_diff number_of_mult[symmetric] number_norm number_eq number_le number_less
       
   187 
       
   188 lemma compute_real_of_nat_number_of: "real ((number_of v)::nat) = (if neg v then 0 else number_of v)"
       
   189   by (simp only: real_of_nat_number_of number_of_is_id)
       
   190 
       
   191 lemma compute_nat_of_int_number_of: "nat ((number_of v)::int) = (number_of v)"
       
   192   by simp
       
   193 
       
   194 lemmas compute_num_conversions = compute_real_of_nat_number_of compute_nat_of_int_number_of real_number_of
       
   195 
       
   196 lemmas zpowerarith = zpower_number_of_even
       
   197   zpower_number_of_odd[simplified zero_eq_Numeral0_nring one_eq_Numeral1_nring]
       
   198   zpower_Pls zpower_Min
       
   199 
       
   200 (* div, mod *)
       
   201 
       
   202 lemma adjust: "adjust b (q, r) = (if 0 \<le> r - b then (2 * q + 1, r - b) else (2 * q, r))"
       
   203   by (auto simp only: adjust_def)
       
   204 
       
   205 lemma negateSnd: "negateSnd (q, r) = (q, -r)" 
       
   206   by (auto simp only: negateSnd_def)
       
   207 
       
   208 lemma divAlg: "divAlg (a, b) = (if 0\<le>a then
       
   209                   if 0\<le>b then posDivAlg a b
       
   210                   else if a=0 then (0, 0)
       
   211                        else negateSnd (negDivAlg (-a) (-b))
       
   212                else 
       
   213                   if 0<b then negDivAlg a b
       
   214                   else negateSnd (posDivAlg (-a) (-b)))"
       
   215   by (auto simp only: divAlg_def)
       
   216 
       
   217 lemmas compute_div_mod = div_def mod_def divAlg adjust negateSnd posDivAlg.simps negDivAlg.simps
       
   218 
       
   219 
       
   220 
       
   221 (* collecting all the theorems *)
       
   222 
       
   223 lemma even_Pls: "even (Numeral.Pls) = True"
       
   224   apply (unfold Pls_def even_def)
       
   225   by simp
       
   226 
       
   227 lemma even_Min: "even (Numeral.Min) = False"
       
   228   apply (unfold Min_def even_def)
       
   229   by simp
       
   230 
       
   231 lemma even_B0: "even (x BIT Numeral.B0) = True"
       
   232   apply (unfold Bit_def)
       
   233   by simp
       
   234 
       
   235 lemma even_B1: "even (x BIT Numeral.B1) = False"
       
   236   apply (unfold Bit_def)
       
   237   by simp
       
   238 
       
   239 lemma even_number_of: "even ((number_of w)::int) = even w"
       
   240   by (simp only: number_of_is_id)
       
   241 
       
   242 lemmas compute_even = even_Pls even_Min even_B0 even_B1 even_number_of
       
   243 
       
   244 lemmas compute_numeral = compute_if compute_let compute_pair compute_bool 
       
   245                          compute_natarith compute_numberarith max_def min_def compute_num_conversions zpowerarith compute_div_mod compute_even
       
   246 
       
   247 end
       
   248 
       
   249 
       
   250