 Usage:  subcs = prunetot (cs, lnum)  
 
 Input:

  cs                     list of vectors: data structure which represents a binary tree 
                         and is produced by cartsplit procedure, contains vectors 
                         cs.val, cs.vec, cs.mean, cs.ssr, cs.nelem. 
                         See cartsplit for the description of cs. 
                         
  lnum                   integer >= 1: the tree subcs will have lnum leaves. 
                         The pruning method produces a sequence of subtrees from 
                         the original tree, the program prunetot selects from that 
                         sequence a tree which has a number of leaves greater or equal 
                         to lnum and then removes subtrees by minimizing sum of rquared 
                         residuals until a subtree with number of leaves exactly to 
                         lnum is formed. 
                         
 Output:

  subcs                  similar kind of object than cs, see cartsplit for the 
                         description of subcs. Number of leaves of subcs is lnum. 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
