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Amadeus W. M.
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 Posted: Fri Feb 24, 2006 5:06 pm Post subject: specialization |
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I have a class
template <class Vector_t>
class A;
where Vector_t is some sort of vector. I want to provide different
specializations for real and for complex vectors. I need the following:
// Real vectors:
A< valarray<double> >; // templated
A< MyRealVector >; // non-tempalted
// Complex vectors:
A< vector< complex<double> >; // templated
A< MyComplexVector >; // non-templated.
Is this possible? How would I do that? Bad design? What's the right way?
Thanks! |
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Victor Bazarov
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| Posted: Fri Feb 24, 2006 6:06 pm Post subject: Re: specialization |
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Amadeus W. M. wrote:
| Quote: | I have a class
template <class Vector_t
class A;
where Vector_t is some sort of vector. I want to provide different
specializations for real and for complex vectors. I need the following:
// Real vectors:
A< valarray<double> >; // templated
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What do you mean by the word 'templated' in the comment?
| Quote: | A< MyRealVector >; // non-tempalted
// Complex vectors:
A< vector< complex<double> >; // templated
A< MyComplexVector >; // non-templated.
Is this possible? How would I do that? Bad design? What's the right way?
|
Have you tried? What's the result? If you haven't, what's stopping you?
What book are you reading that doesn't tell how to specialise a template?
template<> class A<MyRealVector> { /* specialisation */ };
or
typedef A<MyRealVector> MyRealA;
They give you different results, of course. The former would require you
to actually specify the inner workings (which are supposedly different
from the original template), the latter _uses_ the inner workings of the
original template.
V
--
Please remove capital As from my address when replying by mail |
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Amadeus W. M.
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| Posted: Fri Feb 24, 2006 9:06 pm Post subject: Re: specialization |
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On Fri, 24 Feb 2006 12:31:02 -0500, Victor Bazarov wrote:
| Quote: | Amadeus W. M. wrote:
I have a class
template <class Vector_t
class A;
where Vector_t is some sort of vector. I want to provide different
specializations for real and for complex vectors. I need the following:
// Real vectors:
A< valarray<double> >; // templated
What do you mean by the word 'templated' in the comment?
A< MyRealVector >; // non-tempalted
// Complex vectors:
A< vector< complex<double> >; // templated
A< MyComplexVector >; // non-templated.
|
Sorry, I didn't explain very well.
I mean that the template argument of A is itself a template.
So I have the most general
template <class Vector_t>
class A
{
};
I don't want to specialize it to a particular vector type, such as
valarray<double> or MyNonTemplatedVector. The specializations differ in
the SCALAR type of the vector, but should be irrespective of the actual
container. So what I'd like would be rather
template <class Scalar_t, template<class> class Vector_t>
class A
{
// work on Vector_t<Scalar_t>;
};
Then this should somehow be specialized (1) to Scalar_t = float/double and
(2) to Scalar_t = complex<double>, for instance, but still have the
container Vector_t as a parameter.
I'm reading Stroustrup's book. Can this be done?
Even if it CAN be done, with a template Vector_t I won't be able to have a
A<MyNonTemplatedVector>;
Maybe I should just do
template <class Vector_t>
class RealA
{
};
template <class Vector_t>
class ComplexA
{
};
Then Vector_t is the most general, and I have two implementations - one
for real, one for complex. It won't be transparent to the user though. |
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Greg
Guest
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| Posted: Sat Feb 25, 2006 1:06 am Post subject: Re: specialization |
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Amadeus W. M. wrote:
| Quote: | On Fri, 24 Feb 2006 12:31:02 -0500, Victor Bazarov wrote:
Amadeus W. M. wrote:
I have a class
template <class Vector_t
class A;
where Vector_t is some sort of vector. I want to provide different
specializations for real and for complex vectors. I need the following:
// Real vectors:
A< valarray<double> >; // templated
What do you mean by the word 'templated' in the comment?
A< MyRealVector >; // non-tempalted
// Complex vectors:
A< vector< complex<double> >; // templated
A< MyComplexVector >; // non-templated.
Sorry, I didn't explain very well.
I mean that the template argument of A is itself a template.
So I have the most general
template <class Vector_t
class A
{
};
I don't want to specialize it to a particular vector type, such as
valarray<double> or MyNonTemplatedVector. The specializations differ in
the SCALAR type of the vector, but should be irrespective of the actual
container. So what I'd like would be rather
template <class Scalar_t, template<class> class Vector_t
class A
{
// work on Vector_t<Scalar_t>;
};
Then this should somehow be specialized (1) to Scalar_t = float/double and
(2) to Scalar_t = complex<double>, for instance, but still have the
container Vector_t as a parameter.
I'm reading Stroustrup's book. Can this be done?
|
Yes:
template <class Scalar_t, template<class> class Vector_t>
class A
{
// work on Vector_t<Scalar_t>;
};
template < template<class> class Vector_t>
class A<double, Vector_t>
{
};
| Quote: | Even if it CAN be done, with a template Vector_t I won't be able to have a
A<MyNonTemplatedVector>;
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You can if you declare another "A" class template, in addition to the
first.
Greg |
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