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From: Matthias Troyer (troyer_at_[hidden])
Date: 2006-08-24 09:05:31

On Aug 24, 2006, at 7:24 PM, Andy Little wrote:

>> energy = force*distance; // should this be allowed?
>> torque = force*distance; // should this be allowed?
> Quan allows this as it stands.


>> I think that in both cases the implicit conversion from the
>> (annonymous?) quantity force*distance to either energy or torque. I
>> think that to make the library usable one needs to allow these
>> conversions.
> The temporary result of force * distance is a so-called anonymous
> quantity.


>> If one want to prevent the operations then because one is a vector
>> scalar product (the energy) and the other a vector cross product (the
>> torque) then this should be done at the level of the value_type of
>> the quantity and not at the unit level.
> Yes the obvious way to make a quantity a vector quantity is simple.
> Put it as
> the value_type of a vector. Currently quan has 2D and 3D vectors in
> separate
> namespaces, but it was suggested that it would be more flexible to
> just have a
> quan::simple_vector<N_dimensions,quantity> and hopefully that will be
> implemented at some stage.

Why not just use a ublas vector or MTL vector with a quan quantity?
As i mentioned before I see no reason for reinventing the wheel. I
still have not seen your reason for having your own vector classes.


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