The R Project SVN R-packages

#ifndef RPART_NODE_H
#define RPART_NODE_H
/*
** definition of a node in the tree
*
** The actual size of these structures when allocated in insert_split.c
** depends on the split.
** csplit[0] gets used even for continuous splits.
*/
typedef struct split {
    double improve;
    double adj;                 /* for surrogates only, adjusted agreement */
    double spoint;              /* only used if it is continuous */
    struct split *nextsplit;
    int var_num;
    int count;
    int csplit[20];            /* the actual length depends on splitting rule */
} Split, *pSplit;

/* The real 'nodesize' is set in rpart.c */
typedef struct node {
    double risk;                /* risk for the node */
    double complexity;          /* complexity at which it will collapse */
    double sum_wt;              /* sum of the weights for the node  */
    pSplit primary, surrogate;
    struct node *rightson;
    struct node *leftson;
    int num_obs;
    int lastsurrogate;
    double response_est[20];   /* actual length depends on splitting rule */
} Node, *pNode;


typedef struct cptable {
    double cp;
    double risk;
    double xrisk;
    double xstd;
    int nsplit;
    struct cptable *forward, *back;
} cpTable, *CpTable;


/**************************************************************************
*
*  Split:
*      variable number of the split; 0 = no more surrogates (or primaries)
*
*      split point: the actual split point for a continuous
*
*      improve:  For primary splits, the iprovement index returned by the
*                 bsplit routine.  This is the measure that determines the
*                 winning split.
*                For surrogate splits, this holds the error rate, i.e., the
*                 % incorrect guesses of the primary by using this surrogate.
*
*      count: The number of observations split using this variable.  For the
*             first primary, this will = the number of non-missing values.
*             For surrogates, it will be the number missing in the primary
*             and all earlier surrogates but not missing on this one.  (For
*             all primaries but the first, the number is theoretical).
*
*   adj:  Let "maj" be the %agreement for going with the majority,
*                and "agree" the %agreement for this surrogate.  The
*                adjusted value is (agree - maj)/(1-maj); the amount of
*                the potential improvement actually realized.  The denominator
*                for both percents depends on the sur_agree option.
*
*      csplit[0]:   For a continuous variable, we also need to know the
*                    direction of the split.  We use this "extra" variable
*                    as 1: <x to the left, -1: <x to the right.
*
*      csplit[]:    For a categorical, the labels are LEFT, RIGHT, and
*                    0=missing.  (Even if a particular category is not empty,
*                    there may be no subjects from that category present
*                    at a particular split further down the tree).
*
*
*  Node:
*      num_obs: Number of observations in the node.
*
*      response_est: From the eval routine.  Estimate of the response, if
*                      this node were terminal.
*
*      risk: From the eval routine. Estimate of risk, if this node were
*                      terminal.
*
*      complexity: On the way down, it holds equation 5.18.  On the way up
*              it holds a provisional C.P. (The actual C.P. for each node
*              will be the minimum of this number and the provisional C.P.
*              of all nodes above it.  One more pass downward can establish
*              the proper C.P.).
*
*      lastsurrogate: Which direction to send obs for which the primary and
*              all the surrogates are missing.  (The child with the greatest
*       sum of weights).
*/
#endif