tribble               package:splancs               R Documentation

_D_i_g_g_l_e-_R_o_w_l_i_n_g_s_o_n _R_a_i_s_e_d _I_n_c_i_d_e_n_c_e _M_o_d_e_l

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

     Fits the Diggle-Rowlingson Raised Incidence Model.

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

     tribble(ccflag, vars=NULL, alphas=NULL, betas=NULL, rho, 
      which=1:length(alphas), covars=NULL, thetas=NULL, 
      steps=NULL, reqmin=0.001, icount=50, hessian=NULL)

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

  ccflag: Case-control flag : a vector of ones and zeroes. 

    vars: A matrix where `vars[i,j]' is the distance squared from point
          `i'  to source `j'. 

  alphas: Initial value of the `alpha' parameters. 

   betas: Initial value of the `beta' parameters. 

     rho: Initial value of the `rho' parameter. 

   which: Defines the mapping from sources to parameters. 

  covars: A matrix of covariates to be modelled as log-linear terms.
          The element  `covars[i,j]' is the value of covariate `j' for
          case/control `i'. 

  thetas: Initial values of covariate parameters. 

   steps: Step sizes for the Nelder-Mead simplex algorithm. 

  reqmin: Tolerance for simplex algorithm 

  icount: Iteration count for simplex algorithm 

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

     The return value is a list with many components, and class
     `ribfit'.  

  alphas: A vector of the alpha parameters at the maximum

   betas: A vector of the beta values at the maximum

     rho: The value of rho at the maximum

    logl: The maximised log-likelihood

null.logl: The null log-likelihood

    call: The function call to `tribble'

     For further information see Diggle and Rowlingson (1993).

_R_e_f_e_r_e_n_c_e_s:

     Rowlingson, B. and Diggle, P. 1993 Splancs: spatial point pattern
     analysis code in S-Plus.  Computers and Geosciences, 19, 627-655;
     the original sources can be accessed at: <URL:
     http://www.maths.lancs.ac.uk/~rowlings/Splancs/>. See also Bivand,
     R. and Gebhardt, A. 2000 Implementing functions for spatial
     statistical analysis using the R language. Journal of Geographical
     Systems, 2, 307-317.

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

     `triblik', `dsquare'

