[Boost-users] uBLAS - How to use a range of a matrix row?

From: Pascal Bauer (pascal.bauer_at_[hidden])
Date: 2004-08-12 06:39:16

Hi,

I have some (strange?) problems with the ublas: I'm writing a SPH-Code
for fluids and brittle solids. I use a uBLAS matrix to store all the
particle-Data. Now, since the SPH code itself includes a lot of physics,
i wrote a "particle" class, that give me access to the values stored in
the matrix in an intuitive way. As template argument, i'll give a
matrix, so i do no have to take care about matrix internals. It looks
somehow thatlike:

template <typename T>
class Particle
{
  static T& SPHData;         //Matrix where the values are stored
  typename T::size_type GID; //Particle ID 

  (...)

  matrix_row<T> LData;			// Proxy to the particle data
  vector_range<matrix_row<T> > Pos;	// Position vector, for  					//
calculations...

  (...)

  typename T::value_type& mass;  // Reference to physical values...

  Particle(typename T::size_type ParticleID); // Constructor, needs
                                              // Particle ID

}

template <typename T>
Particle<T>::Particle(typename T::size_type ParticleID) :
mass(SPHData(ParticleID, MASS))     // Set the references...
{
  LData.reset(SPHData, ParticleID); // OK, works fine...
  Pos.reset(LData, range(0, 2));    // Give strange error message:
                                    // (at the end of this mail...)
}

I tried different methods to get the Pos to the right place in my
matrix, but if i use the "=" operator, i've got some strange run-time
assertion errors.

My thing is, that i'd like to have a range of a matrix_row or column,
that i can use later for vector-operations. How can I do that?

- Pascal Bauer

PS: Compile Error for my example code.

*/home/pbauer/oosph/src/particlecontainer.h:103: instantiated from
`sph::Particle<T>::Particle(typename T::size_type) [with T =
ParticleTest()::Matrix]' 
*/home/pbauer/oosph/src/test.cpp:36: instantiated from here 
*/usr/include/boost/numeric/ublas/vector_proxy.hpp:126: error: no
matching function for call to `
boost::numeric::ublas::matrix_row<boost::numeric::ublas::matrix<double,
boost::numeric::ublas::row_major,
boost::numeric::ublas::unbounded_array<double> > >::reset(
boost::numeric::ublas::matrix_row<boost::numeric::ublas::matrix<double,
boost::numeric::ublas::row_major,
boost::numeric::ublas::unbounded_array<double> > >&)' 
*/usr/include/boost/numeric/ublas/matrix_proxy.hpp:112: error:
candidates are: void boost::numeric::ublas::matrix_row<E>::reset(M&)
[with M = boost::numeric::ublas::matrix<double,
boost::numeric::ublas::row_major,
boost::numeric::ublas::unbounded_array<double> >] 
*/usr/include/boost/numeric/ublas/matrix_proxy.hpp:117: error: void
boost::numeric::ublas::matrix_row<E>::reset(M&, typename M::size_type)
[with M = boost::numeric::ublas::matrix<double,
boost::numeric::ublas::row_major,
boost::numeric::ublas::unbounded_array<double> >]

-- 
\
|             Pascal Bauer
|
|   Space Research & Planetary Sciences
|            Research Division
|
|           University  of Bern
|
|           Phone: [phone]
|
| e-mail: mailto:pascal.bauer_at_[hidden]
/