const dvector matrix (int tuple) const { return _matrices[tuple]; }
int speaker_for_tuple (int tuple, int which) const { return _speaker_tuples[tuple][which]; }
int n_tuples () const { return _matrices.size(); }
int dimension() const { return _dimension; }
const dvector matrix (int tuple) const { return _matrices[tuple]; }
int speaker_for_tuple (int tuple, int which) const { return _speaker_tuples[tuple][which]; }
int n_tuples () const { return _matrices.size(); }
int dimension() const { return _dimension; }