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Ublas : |
From: Nico Galoppo (ngaloppo_at_[hidden])
Date: 2008-02-06 17:14:50
Thanks, that makes sense, I guess. Still, a little inconvenient.
--nico
On Feb 6, 2008 4:13 PM, Jesse Manning <manning.jesse_at_[hidden]> wrote:
> The problem I think is that the vector class in the Ublas library does not
> have an overloaded operator== function. My guess is that operator== is not
> defined in the library because its meaning could differ depending on how to
> user of the library interprets equality. You could probably write your own
> operator== function so it would compile.
>
>
> Simply comparing 2 ublas::vectors also fails to compile since there is no
> operator== defined as shown below.
>
> // Does not compile
> namespace ublas = boost::numeric::ublas;
>
> int main()
> {
> ublas::vector<int> c(2);
> ublas::vector<int> d(2);
>
> for (int i=0; i < c.size(); ++i)
> {
> c(i) = i;
> d(i) = i;
> }
>
> if (c == d)
> {
> std::cout << "SUCCESS!!!" << std::endl;
> }
>
> return 0;
> }
>
>
> Jesse
>
>
>
> On Feb 6, 2008 3:20 PM, Nico Galoppo <ngaloppo_at_[hidden]> wrote:
> >
> >
> >
> > On a related note, this fails with regular std::vector<> as well (not
> > only multi_array)
> >
> > --nico
> >
> >
> >
> >
> >
> >
> >
> > On Feb 6, 2008 12:22 PM, Nico Galoppo <ngaloppo_at_[hidden]> wrote:
> > > This test program fails to compile on my machine. Can anyone shed some
> > > light on why this is happening?
> > >
> > > #include <boost/numeric/ublas/vector.hpp>
> > > #include <boost/multi_array.hpp>
> > >
> > > int main()
> > > {
> > > typedef boost::numeric::ublas::vector<double> T;
> > > boost::multi_array<T, 2> a,b;
> > >
> > > return (a == b);
> > > }
> > >
> > > $ g++ -I/opt/include test.cpp
> > > /usr/include/c++/4.0.0/bits/stl_algobase.h: In function 'bool
> > > std::equal(_InputIterator1, _InputIterator1, _InputIterator2) [with
> > > _InputIterator1 =
> > > boost::detail::multi_array::array_iterator<main()::T, const
> > > main()::T*, mpl_::size_t<1ul>, const main()::T&>, _InputIterator2 =
> > > boost::detail::multi_array::array_iterator<main()::T, const
> > > main()::T*, mpl_::size_t<1ul>, const main()::T&>]':
> > > /opt/include/boost/multi_array/subarray.hpp:117: instantiated from
> > > 'bool boost::detail::multi_array::const_sub_array<T, NumDims,
> > > TPtr>::operator==(const boost::detail::multi_array::const_sub_array<T,
> > > NumDims, OPtr>&) const [with OPtr = const main()::T*, T = main()::T,
> > > long unsigned int NumDims = 1ul, TPtr = const main()::T*]'
> > > /usr/include/c++/4.0.0/bits/stl_algobase.h:760: instantiated from
> > > 'bool std::equal(_InputIterator1, _InputIterator1, _InputIterator2)
> > > [with _InputIterator1 =
> > > boost::detail::multi_array::array_iterator<main()::T, const
> > > main()::T*, mpl_::size_t<2ul>,
> > > boost::detail::multi_array::const_sub_array<main()::T, 1ul, const
> > > main()::T*> >, _InputIterator2 =
> > > boost::detail::multi_array::array_iterator<main()::T, const
> > > main()::T*, mpl_::size_t<2ul>,
> > > boost::detail::multi_array::const_sub_array<main()::T, 1ul, const
> > > main()::T*> >]'
> > > /opt/include/boost/multi_array/multi_array_ref.hpp:273: instantiated
> > > from 'bool boost::const_multi_array_ref<T, NumDims,
> > > TPtr>::operator==(const boost::const_multi_array_ref<T, NumDims,
> > > OPtr>&) const [with OPtr = main()::T*, T = main()::T, long unsigned
> > > int NumDims = 2ul, TPtr = main()::T*]'
> > > test.cpp:9: instantiated from here
> > > /usr/include/c++/4.0.0/bits/stl_algobase.h:760: error: no match for
> > > 'operator==' in
> > >
> '((boost::iterator_facade<boost::detail::multi_array::array_iterator<main()::T,
> > > const main()::T*, mpl_::size_t<1ul>, const main()::T&>, main()::T,
> > > boost::random_access_traversal_tag, const main()::T&, ptrdiff_t>*)(&
> > > __first1))->boost::iterator_facade<I, V, TC, R, D>::operator* [with
> > > Derived = boost::detail::multi_array::array_iterator<main()::T, const
> > > main()::T*, mpl_::size_t<1ul>, const main()::T&>, Value = main()::T,
> > > CategoryOrTraversal = boost::random_access_traversal_tag, Reference =
> > > const main()::T&, Difference = ptrdiff_t]() ==
> > >
> ((boost::iterator_facade<boost::detail::multi_array::array_iterator<main()::T,
> > > const main()::T*, mpl_::size_t<1ul>, const main()::T&>, main()::T,
> > > boost::random_access_traversal_tag, const main()::T&, ptrdiff_t>*)(&
> > > __first2))->boost::iterator_facade<I, V, TC, R, D>::operator* [with
> > > Derived = boost::detail::multi_array::array_iterator<main()::T, const
> > > main()::T*, mpl_::size_t<1ul>, const main()::T&>, Value = main()::T,
> > > CategoryOrTraversal = boost::random_access_traversal_tag, Reference =
> > > const main()::T&, Difference = ptrdiff_t]()'
> > >
> > >
> > > --
> > > Nico Galoppo :: http://www.ngaloppo.org
> > >
> >
> >
> >
> > --
> > Nico Galoppo :: http://www.ngaloppo.org
> > _______________________________________________
> > ublas mailing list
> > ublas_at_[hidden]
> > http://lists.boost.org/mailman/listinfo.cgi/ublas
> >
>
>
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>
>
-- Nico Galoppo :: http://www.ngaloppo.org