Re: [ublas] Extending type_traits for use with Boost Units

Subject: Re: [ublas] Extending type_traits for use with Boost Units
From: Matthias Schabel (boost_at_[hidden])
Date: 2009-09-03 20:13:19

> Am Wednesday 26 August 2009 schrieb Manoj Rajagopalan:
>> Hi UBLAS developers,
>>
>>  I have begun using Boost Units which was introduced in boost v
>> 1.36. I am working on extending UBLAS to support physically
>> dimensioned types and I have provided a short example below.
>>
>>   This can be achieved efficiently if a few extensions to UBLAS
>> type_traits are allowed and I was wondering if anyone would object to
>> this. An example of such an extension would be the introduction of
>> "sqrt_type" as the type for the square root operation.  This would be
>> the return type for type_traits<T>::type_sqrt(). For arithmetic types
>> like float and double the template can be partially specialized so
>> that sqrt_type is float or double but for physically dimensioned
>> types like quantity<length,double>, sqrt_type can be set to
>> quantity<length^(1/2), double>.
>
> This is a good idea. Could you prepare a patch and a small example
> program?
>
>>    I have already adapted most of vector_expression.hpp for use with
>> these dimensioned quantities with work-arounds for these extensions
>> but this is getting ugly and unwieldy.
>
> is it possible to deduct the square_type from operator*()? E.g., using
> return type deduction (see detail/returntype_deduction and
> promote_traits from traits.hpp)

You might also want to get in touch with Steven Watanabe. I believe he  
has done some work toward making UBLAS and Boost.Units interoperable.

Matthias