Re: [Boost-Users] ublas::matrix sharing storage with ublas::vector

From: jhr.walter_at_[hidden]
Date: 2002-11-28 15:15:13

Kresimir Fresl wrote:

[snip]

> There is a storage class `array_adaptor<>' (in storage.hpp, currently
> undocumented), which adapts some other array to interface
> which ublas classes expect:
> ==============================================
> #include <cstddef>
> #include <iostream>
> 
> #define BOOST_UBLAS_SIMPLE_ARRAY_ADAPTOR
> 
> #include <boost/numeric/ublas/vector.hpp>
> #include <boost/numeric/ublas/matrix.hpp>
> #include <boost/numeric/ublas/io.hpp>
> 
> typedef boost::numeric::ublas::array_adaptor<double> storage_t;
> typedef boost::numeric::ublas::vector<double, storage_t> vct_t;
> typedef boost::numeric::ublas::row_major rm_t;
> typedef boost::numeric::ublas::matrix<double, rm_t, storage_t> matr_t;
> 
> int main() {
> 
>    std::size_t n = 5;
>    std::size_t nxn = n * n;
> 
>    double *a = new double[nxn];
>    storage_t st (nxn, a);
> 
>    vct_t v (nxn, st);
>    for (std::size_t i = 0; i < nxn; ++i)
>      v (i) = i + 0.1;
>    std::cout << v << std::endl;
> 
>    matr_t m (n, n, st);
>    std::cout << m << std::endl;
> 
>    for (std::size_t i = 0; i < n; ++i)
>      for (std::size_t j = 0; j < n; ++j)
>        m (i, j) = 10 * i + j + 0.1;
> 
>    std::cout << v << std::endl;
>    std::cout << m << std::endl;
> 
>    delete[] a;
> }
> ==============================================
> [Note that BOOST_UBLAS_SIMPLE_ARRAY_ADAPTOR must
> be defined. Otherwise array_adaptor<> uses boost::shared_array<>
> which doesn't have operator+, which is in turn needed in some
> functions -- Joerg, are you listening?]

Err, what's up? Oh, a new test case (and a new bug ;-( I'll look into it.

Thanks

Joerg