On Nov 29, 2012, at 11:01 AM, Neil Toronto wrote:
> This is because numbers in [4.0,8.0) have one fewer bit with which to
> represent the fractional part than numbers in [2.0,4.0). That bit is needed
> to represent the larger integer part.
I'm trying to replicate this in Java, using the DecimalFormat class, and I'm
getting
0.225 -> "0.22"
1.225 -> "1.22"
2.225 -> "2.22"
3.225 -> "3.22"
4.225 -> "4.22"
9.225 -> "9.22"
17.225 -> "17.22"
35.225 -> "35.22"
68.225 -> "68.22"
130.225 -> "130.22"
250.225 -> "250.22"
What gives? If Java and Racket are both using IEEE standard double-precision
floating point, and both rounding-to-even (as the DecimalFormat class doc says
it does by default), why am I NEVER getting round-up behavior in Java?
I tried the negations of the same numbers, and they still all end in ".22", as
though it were in round-towards-zero mode, but I queried the rounding mode and
it says it's HALF_EVEN.
The corresponding results in Racket, BTW, are
("0.23" "1.23" "2.23" "3.23" "4.22" "9.22" "17.23" "35.23" "68.22" "130.22"
"250.22")
Stephen Bloch
sbl...@adelphi.edu
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