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Subject: Re: [boost] [fixed_point] Request for interest in a binary fixed point library
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 20120410 16:55:35
Le 10/04/12 19:46, Andrii Sydorchuk a écrit :
>> the recent discussion on the MultiplePrecission Arithmetic library has
>> show that some people has its ow fixed point library.
>
> Could you explain a bit your idea? By fixed point library do you mean fixed
> floatingpoint types (e.g. 1024bit double)?
>
>
Hi,
No. I meant really a fixed, not a floating point, in which the
fractional part is fixed not variable. C++/Boost Chrono is designed in
some way as a fixed point time unit, limited to the use of intmax_t
type as underlying (which is enough to represent the time we want to
represent). My current needs are for small fixedpoint, not for
arbitrary large fixedpoint numbers, so I'll need less than wordbits
fractional numbers.
You can take a look at
http://en.wikipedia.org/wiki/Fixedpoint_arithmetic. This will give you
the context. This C++ proposal
(http://www.openstd.org/jtc1/sc22/wg21/docs/papers/2012/n3352.html) is
quite in line of the design I'm locking for.
The domain is quite related to the quantization (see
http://en.wikipedia.org/wiki/Quantization_%28signal_processing%29 for a
brief overview) where fixedpoint is a way of uniform quantization. For
the applications I'm working on now, I will need also nonuniform
quantizations, as the ones provided by the reverse of a monotonic
function or lookuptables, but this is out of the scope of a fixedpoint
library.
The questions on my initial post are some of the ones we need to answer
when designing such a library.
Hope this clarifies the intent,
Vicente
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