prune                 package:hopach                 R Documentation

_f_u_n_c_t_i_o_n _t_o _p_r_u_n_e _a _H_O_P_A_C_H _t_r_e_e.

_D_e_s_c_r_i_p_t_i_o_n:

     The 'hopach' clustering function identifies a level of the tree
     with minimum MSS as the main clusters and also runs the tree down
     all the way to the final level. The 'prune' function allows one to
     access a level of the tree other than the main clusters or the
     final level.

_U_s_a_g_e:

     prune(data,hobj,level,dmat=NULL,ord="own")

_A_r_g_u_m_e_n_t_s:

    data: data matrix, data frame or exprSet of gene expression
          measurements. Typically, each column corresponds to an array,
          and each row corresponds to a gene. For clustering arrays,
          the arrays appear in the rows and the genes in the columns.
          All values must be numeric. Missing values are ignored.

    hobj: output of the 'hopach' function.

   level: an integer specifying the level to which the tree should be
          pruned - can be greater than or less than the level with the
          main clusters.

    dmat: matrix of pair wise distances between all genes (arrays). All
          values must be numeric. If NULL, this matrix is computed
          using the metric specified by the 'metric' given in hobj. If
          a matrix is provided, the user is responsible for ensuring
          that the metric used agrees with that used in computing hobj.

     ord: character string indicating which of the two orderings
          produced by 'hopach' should be used for the plot. If
          ord="final", the ordering of elements in the final level of
          the hierarchical tree is used. If ord="cluster", the ordering
          from the level of the tree corresponding to the main clusters
          is used. In both cases, the elements from each cluster will
          be contiguous. If ord="final", then the medoid element will
          appear in the middle of each cluster. Else, the ordering
          depends on the value of 'ord' passed to the 'hopach'
          function. If ord="none", then the elements are plotted in the
          same order as in dist.

_V_a_l_u_e:

     A list with the same components as are returned by the 'hopach'
     function. The clustering component now contains the specified
     level instead of the main clusters.

_A_u_t_h_o_r(_s):

     Katherine S. Pollard <kpollard@soe.ucsc.edu> and Mark J. van der
     Laan <laan@stat.berkeley.edu>

_R_e_f_e_r_e_n_c_e_s:

     van der Laan, M.J. and Pollard, K.S. A new algorithm for hybrid
     hierarchical clustering with visualization and the bootstrap.
     Journal of Statistical Planning and Inference, 2003, 117, pp.
     275-303.

     <URL:
     http://www.stat.berkeley.edu/~laan/Research/Research_subpages/Papers/hopach.pdf>

_S_e_e _A_l_s_o:

     'hopach', 'makeoutput'

_E_x_a_m_p_l_e_s:

     mydata<-matrix(rnorm(600),nrow=100)
     mydist<-distancematrix(mydata,d="cosangle")
     clustresult<-hopach(mydata,dmat=mydist)
     level2<-prune(mydata,clustresult,level=2,dmat=mydist,ord="own")
     clustresult$clustering$k
     level2$clustering$k

