src/HOL/Real/float_arith.ML
 changeset 25300 bc3a1c964704 parent 24630 351a308ab58d
```     1.1 --- a/src/HOL/Real/float_arith.ML	Mon Nov 05 22:51:16 2007 +0100
1.2 +++ b/src/HOL/Real/float_arith.ML	Mon Nov 05 22:53:38 2007 +0100
1.3 @@ -87,6 +87,7 @@
1.4  val ln2_10 = Math.ln 10.0 / Math.ln 2.0;
1.5  fun exp5 x = Integer.pow x 5;
1.6  fun exp10 x = Integer.pow x 10;
1.7 +fun exp2 x = Integer.pow x 2;
1.8
1.9  fun find_most_significant q r =
1.10    let
1.11 @@ -101,7 +102,7 @@
1.12          (q * exp10 (r - r') - q', r')
1.13      fun bin2dec d =
1.14        if 0 <= d then
1.15 -        (Integer.square d, 0)
1.16 +        (exp2 d, 0)
1.17        else
1.18          (exp5 (~ d), d)
1.19
1.20 @@ -133,7 +134,7 @@
1.21  fun approx_dec_by_bin n (q,r) =
1.22    let
1.23      fun addseq acc d' [] = acc
1.24 -      | addseq acc d' (d::ds) = addseq (acc + Integer.square (d - d')) d' ds
1.25 +      | addseq acc d' (d::ds) = addseq (acc + exp2 (d - d')) d' ds
1.26
1.27      fun seq2bin [] = (0, 0)
1.28        | seq2bin (d::ds) = (addseq 0 d ds + 1, d)
1.29 @@ -151,7 +152,7 @@
1.30              let
1.31                val d' = d0 - precision
1.32                val x1 = seq2bin (d_seq)
1.33 -              val x2 = (fst x1 * Integer.square (snd x1 - d') + 1,  d') (* = seq2bin (d'::d_seq) *)
1.34 +              val x2 = (fst x1 * exp2 (snd x1 - d') + 1,  d') (* = seq2bin (d'::d_seq) *)
1.35              in
1.36                (x1, x2)
1.37              end
```