JDK 7u-dev review request 8024356: Double.parseDouble() is slow for long Strings

Aleksey Shipilev aleksey.shipilev at oracle.com
Thu Sep 12 14:32:46 UTC 2013

On 09/12/2013 09:17 AM, Dmitry Nadezhin wrote:
> The patch is correct when decimal ULP of kept digits is pow(10,-1075)
> of less. pow(2,53) has 17 decimal decimal digits. MAX_NDIGITS = 1100
> > 1075 + 17 .

OK. That makes more sense. Can we please add the short comment in the
code (maybe next time around)?

I expected to see something like "The value below is chosen as the
conservative threshold. We can demonstrate (<link>) that decimal ulp
should be less than 10^(-1075) to guarantee correctness; we also
compensate for binary mantissa which takes 53 binary digits, or 17
decimal ones. Hence, 1075+17 =~ 1100."


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