I like that idea. We have also been implementing our own floating point numbers with a base of 10, because of requirements in the financial business. I think it should be feasible to write a general wrapper for floating point numbers with an arbitrary base as well. Taking all that together we could have e.g. floating point numbers to a base of 77 with five byte mantissa and 42 bytes exponent, if needed anywhere.
While I agree that this functionality is useful especially for financial problems, but it is probably not a good idea to try to unify it with problem I mentioned. Implementation of extended exponent wrapper around double/float types could be very efficient. As in most cases it uses native double operators (e.g. +,-,*,/,sqrt) plus some additional magic with exponent bits which are stored in int64 for double (or int32 for float). It also satisfies IEEE 754 standard requirement for rounding of the result of next operations +,-,*,/,sqrt without any additional overhead. To be completely clear I didn't define INF and NaN in my implementation as my code is safe of avoiding them. So the main reason against providing generic wrapper to suit both our problems is that probably it won't be so efficient in cases where you just need to extend double/float exponent. However functionality you mentioned will be a good addition as a separate module.
P.S.: Since I am rather new here, can someone please send me a link, where I can teach myself about the boost development process?
I would suggest those links as a good start: http://www.boost.org/development/requirements.html http://www.boost.org/development/submissions.html Andrii On Sun, Dec 25, 2011 at 8:23 AM, Christof Donat <cd@okunah.de> wrote:
Hi,
2) Wrappers around integral floating-point types to support wider exponent
range. Another problem that I faced is conversion from bigint to double. The maximum double exponent is 1023, which is quite small to handle intermediate values of the geometric predicates. I ended up with implementing floating point type wrapper that extends double exponent to int64 range and think it is quite useful feature for problems that operate with big integers.
I like that idea. We have also been implementing our own floating point numbers with a base of 10, because of requirements in the financial business. I think it should be feasible to write a general wrapper for floating point numbers with an arbitrary base as well. Taking all that together we could have e.g. floating point numbers to a base of 77 with five byte mantissa and 42 bytes exponent, if needed anywhere.
Christof
P.S.: Since I am rather new here, can someone please send me a link, where I can teach myself about the boost development process?
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