I have some requests for the uBlas and quaternion libraries, call it my christmas wish-list ;) These are perhaps different topics, but in my current project, they're sort of interwoven. Feel free to pick my mail apart. background: I'm writing a Kalman filter with uBlas, based on Matlab code written by my colleagues. I encountered a few points of improvement (IMO). Maybe these points are not really supposed to be part of uBlas, in which case I would like to see them in some other component ;) wish-list: *** ublas * a solution to the error at the bottom of the mail... *assign an array of values to a vector (of known length) *assign an array of values to a dense matrix (of known size, serialized input) *reverse of these operations *assign a single value to all elements of a vector (of known length) *assign a single value to all elements of a matrix (of known size, serialized input) *assignment of a part of a matrix to a same-size part of another matrix. currently, this has to be done with a number of range-operators. I've written a small wrapper for this, but I think there is a better / cleaner way. template <typename value_type> void assignSubMatrix(boost::numeric::ublas::matrix<value_type>& target, int target_row, int target_col, const boost::numeric::ublas::matrix<value_type>& source, int source_row, int source_col, int cols, int rows) { using namespace boost::numeric::ublas; matrix_range<Matrix> src_range(source,range(source_row,source_col), range(source_row+rows-1,source_col+cols-1)); matrix_range<Matrix> tgt_range(target,range(target_row,target_col), range(target_row+rows-1,target_col+cols-1)); tgt_range = src_range; } ------------------------------------------------------------------------ ---------------------------------------------------------------------- *** quaternion * direct assignment to component 0..3 of the quaternion, i.e. quat.q0 = 1.0 * assignment from a vector / array of values * quaternion to (3x3) rotation matrix (common orientation representation) * quaternion to euler angles (common aerospace orientation representation) * reverse of these operations PS: I have the code for transforming a quaternion to rotation matrix or euler angles if anyone wants to pick this up. ------------------------------------------------------------------------ ---------------------------------------------------------------------- I encountered this error with the ublas library when compiled with Visual C++ 2005 Express. It's probably my own fault, but I can't figure it out. Please explain: // fixed size vector definition #define VECTOR(N,T) class Vector ## N : public blas::vector<T, blas::bounded_array<T,N> > { \ typedef blas::vector<T, blas::bounded_array<T,N> > Base_vector; \ public: \ /* Default construction */ \ Vector ## N () : Base_vector(N) {} \ /* Construction and assignment from an array of values */ \ Vector ## N (const T& value) : Base_vector(N) \ { for (int i=0;i<N;++i) data()[i] = value; } \ /* Construction and assignment from a uBLAS vector expression or copy assignment */ \ template <class R> Vector ## N (const blas::vector_expression<R>& r) : Base_vector(r) {} \ template <class R> void operator=(const blas::vector_expression<R>& r) \ { Base_vector::operator=(r); } \ template <class R> void operator=(const Base_vector& r) \ { Base_vector::operator=(r); } \ void operator=(const T* values) \ { for (int i=0;i<N;++i) data()[i] = values[i]; } \ } VECTOR(3,double); // this defines Vector3, a 3-element vector typedef boost::math::quaternion<double> Quaternion; void determineOrientation(Vector3 acc, Vector3 mag, Quaternion& q_gs) { Vector3 tmp = boost::numeric::ublas::outer_prod(acc,mag); } This gives the following error:
z:\kalman\src\kalmanfiltermt.cpp(129) : error C2440: 'initializing' : cannot convert from 'boost::numeric::ublas::vector_matrix_binary<E1,E2,F>' to 'Vector3' 1> with 1> [ 1> E1=boost::numeric::ublas::vector<double,boost::numeric::ublas::bounded_a rray<double,3>>, 1> E2=boost::numeric::ublas::vector<double,boost::numeric::ublas::bounded_a rray<double,3>>, 1> F=boost::numeric::ublas::scalar_multiplies<double,double> 1> ] 1> No constructor could take the source type, or constructor overload resolution was ambiguous
I've tried many different explicit template instantiations for outer_prod, but I don't know which to use, since none of them worked. ----------------------------------------------------------------------- Job P. Mulder Software Engineer Xsens Motion Technologies B.V. http://www.xsens.com