11 exception Floating_point of string |
11 exception Floating_point of string |
12 |
12 |
13 type floatrep = IntInf.int * IntInf.int |
13 type floatrep = IntInf.int * IntInf.int |
14 val approx_dec_by_bin : IntInf.int -> floatrep -> floatrep * floatrep |
14 val approx_dec_by_bin : IntInf.int -> floatrep -> floatrep * floatrep |
15 val approx_decstr_by_bin : int -> string -> floatrep * floatrep |
15 val approx_decstr_by_bin : int -> string -> floatrep * floatrep |
16 end |
16 end |
17 = |
17 = |
18 struct |
18 struct |
19 |
19 |
20 exception Destruct_floatstr of string; |
20 exception Destruct_floatstr of string; |
21 |
21 |
22 fun destruct_floatstr isDigit isExp number = |
22 fun destruct_floatstr isDigit isExp number = |
23 let |
23 let |
24 val numlist = filter (not o Char.isSpace) (String.explode number) |
24 val numlist = filter (not o Char.isSpace) (String.explode number) |
25 |
25 |
26 fun countsigns ((#"+")::cs) = countsigns cs |
26 fun countsigns ((#"+")::cs) = countsigns cs |
27 | countsigns ((#"-")::cs) = |
27 | countsigns ((#"-")::cs) = |
28 let |
28 let |
29 val (positive, rest) = countsigns cs |
29 val (positive, rest) = countsigns cs |
30 in |
30 in |
31 (not positive, rest) |
31 (not positive, rest) |
32 end |
32 end |
33 | countsigns cs = (true, cs) |
33 | countsigns cs = (true, cs) |
34 |
34 |
35 fun readdigits [] = ([], []) |
35 fun readdigits [] = ([], []) |
36 | readdigits (q as c::cs) = |
36 | readdigits (q as c::cs) = |
37 if (isDigit c) then |
37 if (isDigit c) then |
38 let |
38 let |
39 val (digits, rest) = readdigits cs |
39 val (digits, rest) = readdigits cs |
40 in |
40 in |
41 (c::digits, rest) |
41 (c::digits, rest) |
42 end |
42 end |
43 else |
43 else |
44 ([], q) |
44 ([], q) |
45 |
45 |
46 fun readfromexp_helper cs = |
46 fun readfromexp_helper cs = |
47 let |
47 let |
48 val (positive, rest) = countsigns cs |
48 val (positive, rest) = countsigns cs |
49 val (digits, rest') = readdigits rest |
49 val (digits, rest') = readdigits rest |
50 in |
50 in |
51 case rest' of |
51 case rest' of |
52 [] => (positive, digits) |
52 [] => (positive, digits) |
53 | _ => raise (Destruct_floatstr number) |
53 | _ => raise (Destruct_floatstr number) |
54 end |
54 end |
55 |
55 |
56 fun readfromexp [] = (true, []) |
56 fun readfromexp [] = (true, []) |
57 | readfromexp (c::cs) = |
57 | readfromexp (c::cs) = |
58 if isExp c then |
58 if isExp c then |
59 readfromexp_helper cs |
59 readfromexp_helper cs |
60 else |
60 else |
61 raise (Destruct_floatstr number) |
61 raise (Destruct_floatstr number) |
62 |
62 |
63 fun readfromdot [] = ([], readfromexp []) |
63 fun readfromdot [] = ([], readfromexp []) |
64 | readfromdot ((#".")::cs) = |
64 | readfromdot ((#".")::cs) = |
65 let |
65 let |
66 val (digits, rest) = readdigits cs |
66 val (digits, rest) = readdigits cs |
67 val exp = readfromexp rest |
67 val exp = readfromexp rest |
68 in |
68 in |
69 (digits, exp) |
69 (digits, exp) |
70 end |
70 end |
71 | readfromdot cs = readfromdot ((#".")::cs) |
71 | readfromdot cs = readfromdot ((#".")::cs) |
72 |
72 |
73 val (positive, numlist) = countsigns numlist |
73 val (positive, numlist) = countsigns numlist |
74 val (digits1, numlist) = readdigits numlist |
74 val (digits1, numlist) = readdigits numlist |
75 val (digits2, exp) = readfromdot numlist |
75 val (digits2, exp) = readfromdot numlist |
76 in |
76 in |
77 (positive, String.implode digits1, String.implode digits2, fst exp, String.implode (snd exp)) |
77 (positive, String.implode digits1, String.implode digits2, fst exp, String.implode (snd exp)) |
78 end |
78 end |
79 |
79 |
80 type floatrep = IntInf.int * IntInf.int |
80 type floatrep = IntInf.int * IntInf.int |
81 |
81 |
82 exception Floating_point of string; |
82 exception Floating_point of string; |
83 |
83 |
84 val ln2_10 = (Math.ln 10.0)/(Math.ln 2.0) |
84 val ln2_10 = (Math.ln 10.0)/(Math.ln 2.0) |
85 |
85 |
86 fun intmul a b = IntInf.* (a,b) |
86 fun intmul a b = IntInf.* (a,b) |
87 fun intsub a b = IntInf.- (a,b) |
87 fun intsub a b = IntInf.- (a,b) |
88 fun intadd a b = IntInf.+ (a,b) |
88 fun intadd a b = IntInf.+ (a,b) |
89 fun intpow a b = IntInf.pow (a, IntInf.toInt b); |
89 fun intpow a b = IntInf.pow (a, IntInf.toInt b); |
90 fun intle a b = IntInf.<= (a, b); |
90 fun intle a b = IntInf.<= (a, b); |
91 fun intless a b = IntInf.< (a, b); |
91 fun intless a b = IntInf.< (a, b); |
92 fun intneg a = IntInf.~ a; |
92 fun intneg a = IntInf.~ a; |
93 val zero = IntInf.fromInt 0; |
93 val zero = IntInf.fromInt 0; |
94 val one = IntInf.fromInt 1; |
94 val one = IntInf.fromInt 1; |
95 val two = IntInf.fromInt 2; |
95 val two = IntInf.fromInt 2; |
96 val ten = IntInf.fromInt 10; |
96 val ten = IntInf.fromInt 10; |
97 val five = IntInf.fromInt 5; |
97 val five = IntInf.fromInt 5; |
98 |
98 |
99 fun find_most_significant q r = |
99 fun find_most_significant q r = |
100 let |
100 let |
101 fun int2real i = |
101 fun int2real i = |
102 case Real.fromString (IntInf.toString i) of |
102 case Real.fromString (IntInf.toString i) of |
103 SOME r => r |
103 SOME r => r |
104 | NONE => raise (Floating_point "int2real") |
104 | NONE => raise (Floating_point "int2real") |
105 fun subtract (q, r) (q', r') = |
105 fun subtract (q, r) (q', r') = |
106 if intle r r' then |
106 if intle r r' then |
107 (intsub q (intmul q' (intpow ten (intsub r' r))), r) |
107 (intsub q (intmul q' (intpow ten (intsub r' r))), r) |
108 else |
108 else |
109 (intsub (intmul q (intpow ten (intsub r r'))) q', r') |
109 (intsub (intmul q (intpow ten (intsub r r'))) q', r') |
110 fun bin2dec d = |
110 fun bin2dec d = |
111 if intle zero d then |
111 if intle zero d then |
112 (intpow two d, zero) |
112 (intpow two d, zero) |
113 else |
113 else |
114 (intpow five (intneg d), d) |
114 (intpow five (intneg d), d) |
115 |
115 |
116 val L = IntInf.fromInt (Real.floor (int2real (IntInf.fromInt (IntInf.log2 q)) + (int2real r) * ln2_10)) |
116 val L = IntInf.fromInt (Real.floor (int2real (IntInf.fromInt (IntInf.log2 q)) + (int2real r) * ln2_10)) |
117 val L1 = intadd L one |
117 val L1 = intadd L one |
118 |
118 |
119 val (q1, r1) = subtract (q, r) (bin2dec L1) |
119 val (q1, r1) = subtract (q, r) (bin2dec L1) |
120 in |
120 in |
121 if intle zero q1 then |
121 if intle zero q1 then |
122 let |
122 let |
123 val (q2, r2) = subtract (q, r) (bin2dec (intadd L1 one)) |
123 val (q2, r2) = subtract (q, r) (bin2dec (intadd L1 one)) |
124 in |
124 in |
125 if intle zero q2 then |
125 if intle zero q2 then |
126 raise (Floating_point "find_most_significant") |
126 raise (Floating_point "find_most_significant") |
127 else |
127 else |
128 (L1, (q1, r1)) |
128 (L1, (q1, r1)) |
129 end |
129 end |
130 else |
130 else |
133 in |
133 in |
134 if intle zero q0 then |
134 if intle zero q0 then |
135 (L, (q0, r0)) |
135 (L, (q0, r0)) |
136 else |
136 else |
137 raise (Floating_point "find_most_significant") |
137 raise (Floating_point "find_most_significant") |
138 end |
138 end |
139 end |
139 end |
140 |
140 |
141 fun approx_dec_by_bin n (q,r) = |
141 fun approx_dec_by_bin n (q,r) = |
142 let |
142 let |
143 fun addseq acc d' [] = acc |
143 fun addseq acc d' [] = acc |
144 | addseq acc d' (d::ds) = addseq (intadd acc (intpow two (intsub d d'))) d' ds |
144 | addseq acc d' (d::ds) = addseq (intadd acc (intpow two (intsub d d'))) d' ds |
145 |
145 |
146 fun seq2bin [] = (zero, zero) |
146 fun seq2bin [] = (zero, zero) |
147 | seq2bin (d::ds) = (intadd (addseq zero d ds) one, d) |
147 | seq2bin (d::ds) = (intadd (addseq zero d ds) one, d) |
148 |
148 |
149 fun approx d_seq d0 precision (q,r) = |
149 fun approx d_seq d0 precision (q,r) = |
150 if q = zero then |
150 if q = zero then |
151 let val x = seq2bin d_seq in |
151 let val x = seq2bin d_seq in |
152 (x, x) |
152 (x, x) |
153 end |
153 end |
154 else |
154 else |
155 let |
155 let |
156 val (d, (q', r')) = find_most_significant q r |
156 val (d, (q', r')) = find_most_significant q r |
157 in |
157 in |
158 if intless precision (intsub d0 d) then |
158 if intless precision (intsub d0 d) then |
159 let |
159 let |
160 val d' = intsub d0 precision |
160 val d' = intsub d0 precision |
161 val x1 = seq2bin (d_seq) |
161 val x1 = seq2bin (d_seq) |
162 val x2 = (intadd (intmul (fst x1) (intpow two (intsub (snd x1) d'))) one, d') (* = seq2bin (d'::d_seq) *) |
162 val x2 = (intadd (intmul (fst x1) (intpow two (intsub (snd x1) d'))) one, d') (* = seq2bin (d'::d_seq) *) |
163 in |
163 in |
164 (x1, x2) |
164 (x1, x2) |
165 end |
165 end |
166 else |
166 else |
167 approx (d::d_seq) d0 precision (q', r') |
167 approx (d::d_seq) d0 precision (q', r') |
168 end |
168 end |
169 |
169 |
170 fun approx_start precision (q, r) = |
170 fun approx_start precision (q, r) = |
171 if q = zero then |
171 if q = zero then |
172 ((zero, zero), (zero, zero)) |
172 ((zero, zero), (zero, zero)) |
173 else |
173 else |
174 let |
174 let |
175 val (d, (q', r')) = find_most_significant q r |
175 val (d, (q', r')) = find_most_significant q r |
176 in |
176 in |
177 if intle precision zero then |
177 if intle precision zero then |
178 let |
178 let |
179 val x1 = seq2bin [d] |
179 val x1 = seq2bin [d] |
180 in |
180 in |
181 if q' = zero then |
181 if q' = zero then |
182 (x1, x1) |
182 (x1, x1) |
183 else |
183 else |
184 (x1, seq2bin [intadd d one]) |
184 (x1, seq2bin [intadd d one]) |
185 end |
185 end |
186 else |
186 else |
187 approx [d] d precision (q', r') |
187 approx [d] d precision (q', r') |
188 end |
188 end |
189 in |
189 in |
190 if intle zero q then |
190 if intle zero q then |
191 approx_start n (q,r) |
191 approx_start n (q,r) |
192 else |
192 else |
193 let |
193 let |
194 val ((a1,b1), (a2, b2)) = approx_start n (intneg q, r) |
194 val ((a1,b1), (a2, b2)) = approx_start n (intneg q, r) |
195 in |
195 in |
196 ((intneg a2, b2), (intneg a1, b1)) |
196 ((intneg a2, b2), (intneg a1, b1)) |
197 end |
197 end |
198 end |
198 end |
199 |
199 |
200 fun approx_decstr_by_bin n decstr = |
200 fun approx_decstr_by_bin n decstr = |
201 let |
201 let |
202 fun str2int s = case IntInf.fromString s of SOME x => x | NONE => zero |
202 fun str2int s = case IntInf.fromString s of SOME x => x | NONE => zero |
203 fun signint p x = if p then x else intneg x |
203 fun signint p x = if p then x else intneg x |
204 |
204 |
205 val (p, d1, d2, ep, e) = destruct_floatstr Char.isDigit (fn e => e = #"e" orelse e = #"E") decstr |
205 val (p, d1, d2, ep, e) = destruct_floatstr Char.isDigit (fn e => e = #"e" orelse e = #"E") decstr |
206 val s = IntInf.fromInt (size d2) |
206 val s = IntInf.fromInt (size d2) |
207 |
207 |
208 val q = signint p (intadd (intmul (str2int d1) (intpow ten s)) (str2int d2)) |
208 val q = signint p (intadd (intmul (str2int d1) (intpow ten s)) (str2int d2)) |
209 val r = intsub (signint ep (str2int e)) s |
209 val r = intsub (signint ep (str2int e)) s |
210 in |
210 in |
211 approx_dec_by_bin (IntInf.fromInt n) (q,r) |
211 approx_dec_by_bin (IntInf.fromInt n) (q,r) |
212 end |
212 end |
213 |
213 |
214 end; |
214 end; |
215 |
215 |
216 structure FloatArith = |
216 structure FloatArith = |
217 struct |
217 struct |
218 |
218 |
219 type float = IntInf.int * IntInf.int |
219 type float = IntInf.int * IntInf.int |
220 |
220 |
221 val izero = IntInf.fromInt 0 |
221 val izero = IntInf.fromInt 0 |
222 val ione = IntInf.fromInt 1 |
222 val ione = IntInf.fromInt 1 |
223 val imone = IntInf.fromInt ~1 |
223 val imone = IntInf.fromInt ~1 |
224 val itwo = IntInf.fromInt 2 |
224 val itwo = IntInf.fromInt 2 |
226 fun isub a b = IntInf.- (a,b) |
226 fun isub a b = IntInf.- (a,b) |
227 fun iadd a b = IntInf.+ (a,b) |
227 fun iadd a b = IntInf.+ (a,b) |
228 |
228 |
229 val floatzero = (izero, izero) |
229 val floatzero = (izero, izero) |
230 |
230 |
231 fun positive_part (a,b) = |
231 fun positive_part (a,b) = |
232 (if IntInf.< (a,izero) then izero else a, b) |
232 (if IntInf.< (a,izero) then izero else a, b) |
233 |
233 |
234 fun negative_part (a,b) = |
234 fun negative_part (a,b) = |
235 (if IntInf.< (a,izero) then a else izero, b) |
235 (if IntInf.< (a,izero) then a else izero, b) |
236 |
236 |
237 fun is_negative (a,b) = |
237 fun is_negative (a,b) = |
238 if IntInf.< (a, izero) then true else false |
238 if IntInf.< (a, izero) then true else false |
239 |
239 |
240 fun is_positive (a,b) = |
240 fun is_positive (a,b) = |
241 if IntInf.< (izero, a) then true else false |
241 if IntInf.< (izero, a) then true else false |
242 |
242 |
243 fun is_zero (a,b) = |
243 fun is_zero (a,b) = |
244 if a = izero then true else false |
244 if a = izero then true else false |
245 |
245 |
246 fun ipow2 a = IntInf.pow ((IntInf.fromInt 2), IntInf.toInt a) |
246 fun ipow2 a = IntInf.pow ((IntInf.fromInt 2), IntInf.toInt a) |
247 |
247 |
248 fun add (a1, b1) (a2, b2) = |
248 fun add (a1, b1) (a2, b2) = |
249 if IntInf.< (b1, b2) then |
249 if IntInf.< (b1, b2) then |
250 (iadd a1 (imul a2 (ipow2 (isub b2 b1))), b1) |
250 (iadd a1 (imul a2 (ipow2 (isub b2 b1))), b1) |
251 else |
251 else |
252 (iadd (imul a1 (ipow2 (isub b1 b2))) a2, b2) |
252 (iadd (imul a1 (ipow2 (isub b1 b2))) a2, b2) |
253 |
253 |
254 fun sub (a1, b1) (a2, b2) = |
254 fun sub (a1, b1) (a2, b2) = |
255 if IntInf.< (b1, b2) then |
255 if IntInf.< (b1, b2) then |
256 (isub a1 (imul a2 (ipow2 (isub b2 b1))), b1) |
256 (isub a1 (imul a2 (ipow2 (isub b2 b1))), b1) |
257 else |
257 else |
258 (isub (imul a1 (ipow2 (isub b1 b2))) a2, b2) |
258 (isub (imul a1 (ipow2 (isub b1 b2))) a2, b2) |
259 |
259 |
335 val float_nprt_const = Const ("OrderedGroup.nprt", HOLogic.realT --> HOLogic.realT) |
335 val float_nprt_const = Const ("OrderedGroup.nprt", HOLogic.realT --> HOLogic.realT) |
336 |
336 |
337 val nat_le_const = Const ("Orderings.less_eq", HOLogic.natT --> HOLogic.natT --> HOLogic.boolT) |
337 val nat_le_const = Const ("Orderings.less_eq", HOLogic.natT --> HOLogic.natT --> HOLogic.boolT) |
338 val nat_less_const = Const ("Orderings.less", HOLogic.natT --> HOLogic.natT --> HOLogic.boolT) |
338 val nat_less_const = Const ("Orderings.less", HOLogic.natT --> HOLogic.natT --> HOLogic.boolT) |
339 val nat_eq_const = Const ("op =", HOLogic.natT --> HOLogic.natT --> HOLogic.boolT) |
339 val nat_eq_const = Const ("op =", HOLogic.natT --> HOLogic.natT --> HOLogic.boolT) |
340 |
340 |
341 val zero = FloatArith.izero |
341 val zero = FloatArith.izero |
342 val minus_one = FloatArith.imone |
342 val minus_one = FloatArith.imone |
343 val two = FloatArith.itwo |
343 val two = FloatArith.itwo |
344 |
344 |
345 exception Dest_intinf; |
345 exception Dest_intinf; |
346 exception Dest_float; |
346 exception Dest_float; |
347 |
347 |
348 fun mk_intinf ty n = |
348 fun mk_intinf ty n = HOLogic.number_of_const ty $ HOLogic.mk_numeral n; |
349 let |
349 |
350 fun mk_bit n = if n = zero then HOLogic.B0_const else HOLogic.B1_const |
350 val dest_intinf = snd o HOLogic.dest_number |
351 fun bin_of n = |
351 |
352 if n = zero then HOLogic.pls_const |
352 fun mk_float (a,b) = |
353 else if n = minus_one then HOLogic.min_const |
|
354 else let |
|
355 val (q,r) = IntInf.divMod (n, two) |
|
356 in |
|
357 HOLogic.bit_const $ bin_of q $ mk_bit r |
|
358 end |
|
359 in |
|
360 HOLogic.number_of_const ty $ (bin_of n) |
|
361 end |
|
362 |
|
363 fun dest_intinf n = |
|
364 let |
|
365 fun dest_bit n = |
|
366 case n of |
|
367 Const ("Numeral.bit.B0", _) => FloatArith.izero |
|
368 | Const ("Numeral.bit.B1", _) => FloatArith.ione |
|
369 | _ => raise Dest_intinf |
|
370 |
|
371 fun int_of n = |
|
372 case n of |
|
373 Const ("Numeral.Pls", _) => FloatArith.izero |
|
374 | Const ("Numeral.Min", _) => FloatArith.imone |
|
375 | Const ("Numeral.Bit", _) $ q $ r => FloatArith.iadd (FloatArith.imul (int_of q) FloatArith.itwo) (dest_bit r) |
|
376 | _ => raise Dest_intinf |
|
377 in |
|
378 case n of |
|
379 Const ("Numeral.number_of", _) $ n' => int_of n' |
|
380 | Const ("Numeral0", _) => FloatArith.izero |
|
381 | Const ("Numeral1", _) => FloatArith.ione |
|
382 | _ => raise Dest_intinf |
|
383 end |
|
384 |
|
385 fun mk_float (a,b) = |
|
386 float_const $ (HOLogic.mk_prod ((mk_intinf HOLogic.intT a), (mk_intinf HOLogic.intT b))) |
353 float_const $ (HOLogic.mk_prod ((mk_intinf HOLogic.intT a), (mk_intinf HOLogic.intT b))) |
387 |
354 |
388 fun dest_float f = |
355 fun dest_float f = |
389 case f of |
356 case f of |
390 (Const ("Float.float", _) $ (Const ("Pair", _) $ a $ b)) => (dest_intinf a, dest_intinf b) |
357 (Const ("Float.float", _) $ (Const ("Pair", _) $ a $ b)) => (dest_intinf a, dest_intinf b) |
391 | Const ("Numeral.number_of",_) $ a => (dest_intinf f, 0) |
358 | Const ("Numeral.number_of",_) $ a => (dest_intinf f, 0) |
392 | Const ("Numeral0", _) => (FloatArith.izero, FloatArith.izero) |
359 | Const ("Numeral0", _) => (FloatArith.izero, FloatArith.izero) |
393 | Const ("Numeral1", _) => (FloatArith.ione, FloatArith.izero) |
360 | Const ("Numeral1", _) => (FloatArith.ione, FloatArith.izero) |
394 | _ => raise Dest_float |
361 | _ => raise Dest_float |
395 |
362 |
396 fun dest_nat n = |
363 fun dest_nat n = |
397 let |
364 let |
398 val v = dest_intinf n |
365 val v = dest_intinf n |
399 in |
366 in |
400 if IntInf.< (v, FloatArith.izero) then |
367 if IntInf.< (v, FloatArith.izero) then |
401 FloatArith.izero |
368 FloatArith.izero |
402 else |
369 else |
403 v |
370 v |
404 end |
371 end |
405 |
372 |
406 fun approx_float prec f value = |
373 fun approx_float prec f value = |
407 let |
374 let |
408 val interval = ExactFloatingPoint.approx_decstr_by_bin prec value |
375 val interval = ExactFloatingPoint.approx_decstr_by_bin prec value |
409 val (flower, fupper) = f interval |
376 val (flower, fupper) = f interval |
410 in |
377 in |
411 (mk_float flower, mk_float fupper) |
378 (mk_float flower, mk_float fupper) |