REBUILD                 package:PTAk                 R Documentation

_B_u_i_l_d _a_n _a_p_p_r_o_x_i_m_a_t_i_o_n _o_f _t_h_e _t_e_n_s_o_r _o_f _a_n_y _o_r_d_e_r

_D_e_s_c_r_i_p_t_i_o_n:

     Gives the approximation of a previously analysed tensor using its
     given decomposition.

_U_s_a_g_e:

      REBUILD(solutions,nTens=1:2,testvar=1 ,redundancy=FALSE)

_A_r_g_u_m_e_n_t_s:

solutions: a `solutions.PTAk' object

   nTens: a vector of identifying positions (numbers given in
          `summary') for  the choice of Principal Tensors to use

 testvar: control within `nTens' used Principal Tensor with  minimum
          percent of variability explained

redundancy: logical to take into account (within `nTens') PT tested
          redundant during analysis (seealso `RESUM') if `TRUE'.

_D_e_t_a_i_l_s:

     The function rebuilds the Principal Tensors, i.e. rank-one tensors
     of order the order of the tensor analysed, and add them up to
     build an approximation of the tensor analysed (according to the
     method used see `method'). This constitutes a best Least Squares
     (ordinary or "weighted"  if metrics are used) approximation of
     `datanam' for a given orthogonal-rank r (number of principal
     tensors used), if and only if the singular values used are the r
     highest.

_V_a_l_u_e:

     A tensor with dimensions as `solutions[[k]][["datanam"]]'.

_N_o_t_e:

     This function can be called for `PARAFAC/CANDECOMP' and `PCAn'. A
     specific rebuilt is implemented for this last one.

_A_u_t_h_o_r(_s):

     Didier Leibovici didier@fmrib.ox.ac.uk

_S_e_e _A_l_s_o:

     `PTAk'

