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Subject: Re: [boost] GSOC 2013
From: Michael Marcin (mike.marcin_at_[hidden])
Date: 20130420 00:14:12
On 4/19/2013 7:15 PM, Vicente J. Botet Escriba wrote:
> Le 18/04/13 15:39, Dmitriy Gorbel a écrit :
>> I want to provide my proposal to the Boost community.
>>
>> Please, lets discuss it! I will be grateful for your reviews and advices.
>> How can I improve it?
>> I appreciate any feedback you may have.
>>
>> proposal_Dmitriy_Gorbel.pdf
>> <http://boost.2283326.n4.nabble.com/file/n4645577/proposal_Dmitriy_Gorbel.pdf>
>>
>
> <snip very good feedback>
>
There is a typo: The range must be *grater* then the resolution
I don't understand your types.
cardinal<16> 0 <= n <= 65536
This seems to be a 16 bit unsigned type but requires 17 bits to store
this range. It should probably be 0 <= n <= 65535.
integral<4> 16 <= n <= 16
Similar here this seem to be a 5 it signed integer but requires 6 bits
to store this range. It should probably be 16 <= n <= 15.
nonnegative<8,4> 256 < n < 256 in increments of 2^4 = 1/16
I don't understand how a type nonnegative can store values in (256,0).
negatable<16,8> 65536 < n < 65536 in increments of 2^8
= 1/ 256
This seems close to a fixed point type as I'm used to seeing it.
Although again the ranges seem wrong.
I'm much more accustom to seeing fixed point number specified as
<Magnitude bits, Fractional Bits> i.e. <16,8> instead of <16,8>.
Still this representation makes sense because it specifies both
parameters in terms 2^x. It also supports something like <17,1> to give
a 16 bit type that has the range [131072, 131071] in increments of 2.
Still it might be surprising to those familiar with the more common
fixedpoint notation.
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