Re: [boost] [Multiprecision] Benchmarking

Subject: Re: [boost] [Multiprecision] Benchmarking
From: Vicente Botet (vicente.botet_at_[hidden])
Date: 2012-06-15 07:24:22

John Maddock-3 wrote
> 
>>I agree, the library should be able to decide whether expression templates 
>>should be an improvement or not.
>>
>>A minor change in the library, defaulting the ExpressionTemplates
parameter 
>>to a trait depending on the backend could help to that.
>>The library could default to something reasonable, while the backend 
>>developer could always provide a specialization.
> 
> That would certainly be easy to do, but:
> 
> * That wouldn't help for types like cpp_int where the best strategy may 
> depend on the runtime size of the number.
> 
> 
>> 
>> The backend developer could define the trait depending on the
>> compile-time size. For run-time size the library set use a default, and
>> it will be up to the user to force or not the use of expression
>> templates.
>>  
>> 
> * How would this differ in practice from the use of the typedefs we
> already 
> provide where we know that expression templates don't help (mp_intXXX_t 
> etc)?
> 

Well, you will not have specific typedefs for all the sizes, so a way to
associate the default value will be convenient.

Vicente

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