xpnd                package:MCMCpack                R Documentation

_E_x_p_a_n_d _a _V_e_c_t_o_r _i_n_t_o _a _S_y_m_m_e_t_r_i_c _M_a_t_r_i_x

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

     This function takes a vector of appropriate length (typically
     created using 'vech') and creates a symmetric matrix.

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

        xpnd(x, nrow)

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

       x: A list of elements to expand into symmetric matrix.

    nrow: The number of rows (and columns) in the returned matrix.

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

     This function is particularly useful when dealing with variance
     covariance matrices. Note that R stores matrices in column major
     order, and that the items in 'x' will be recycled to fill the
     matrix if need be.

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

     An (nrows * nrows) symmetric matrix.

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

     'vech'

_E_x_a_m_p_l_e_s:

       xpnd(c(1,2,3,4,4,5,6,7,8,9),4)

