[pspp] / src / math / categoricals.c

/* PSPP - a program for statistical analysis.
   Copyright (C) 2009 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>. */

#include <config.h>

#include <stdio.h>

#include "categoricals.h"

#include <gl/xalloc.h>
#include <data/variable.h>
#include <data/case.h>
#include <data/value.h>
#include <libpspp/hmap.h>
#include <libpspp/pool.h>

#include <libpspp/str.h>

struct value_node
{
  struct hmap_node node;      /* Node in hash map. */
  union value value;          /* The value being labeled. */
  double cc;                  /* The total of the weights of cases with this value */

  void *user_data;            /* A pointer to data which the caller can store stuff */

  int subscript;              /* A zero based integer, unique within the variable.
                                 Can be used as an index into an array */
};


struct var_params
{
  /* A map indexed by a union values */
  struct hmap map;

  const struct variable *var;

  int base_subscript;

  /* The number of distinct values of this variable */
  int n_cats;

  /* A map of values indexed by subscript */
  const struct value_node **reverse_value_map;

  /* Total of the weights of this variable */
  double cc; 
};


struct categoricals
{
  /* The weight variable */
  const struct variable *wv;


  /* An array of var_params */
  struct var_params *vp;

  /* The size of VP. (ie, the number of variables involved.) */
  size_t n_vp;

  /* The number of categorical variables which contain entries.
     In the absence of missing values, this will be equal to N_VP */
  size_t n_vars;

  /* A map to enable the lookup of variables indexed by subscript */
  int *reverse_variable_map;

  size_t n_cats_total;

  struct pool *pool;

  /* Missing values to be excluded */
  enum mv_class exclude;



  /* Function to be called on each update */
  update_func *update;

  /* Auxilliary data to be passed to update */
  void *update_aux;

  /* Function specified by the caller to create user_data */
  user_data_create_func *user_data_create;
};


void
categoricals_destroy ( struct categoricals *cat)
{
  int i;
  if (cat != NULL)
    {
      for (i = 0 ; i < cat->n_vp; ++i)
        hmap_destroy (&cat->vp[i].map);
      
      pool_destroy (cat->pool);
      free (cat);
    }
}


#if 0
void
categoricals_dump (const struct categoricals *cat)
{
  int v;

  for (v = 0 ; v < cat->n_vp; ++v)
    {
      const struct var_params *vp = &cat->vp[v];
      const struct hmap *m = &vp->map;
      struct hmap_node *node ;
      int x;
     
      printf ("\n%s (%d)  CC=%g n_cats=%d:\n", 
              var_get_name (vp->var), vp->base_subscript, vp->cc, vp->n_cats);

      printf ("Reverse map\n");
      for (x = 0 ; x < vp->n_cats; ++x)
        {
          struct string s;
          const struct value_node *vn = vp->reverse_value_map[x];
          ds_init_empty (&s);
          var_append_value_name (vp->var, &vn->value, &s);
          printf ("Value for %d is %s\n", x, ds_cstr(&s));
          ds_destroy (&s);
        }

      printf ("\nForward map\n");
      for (node = hmap_first (m); node; node = hmap_next (m, node))
        {
          struct string s;
          const struct value_node *vn = HMAP_DATA (node, struct value_node, node);
          ds_init_empty (&s);
          var_append_value_name (vp->var, &vn->value, &s);
          printf ("Value: %s; Index %d; CC %g\n",
                  ds_cstr (&s),
                  vn->subscript, vn->cc);
          ds_destroy (&s);
        }
    }

  assert (cat->n_vars <= cat->n_vp);

  printf ("\n");
  printf ("Number of categorical variables: %d\n", cat->n_vp);
  printf ("Number of non-empty categorical variables: %d\n", cat->n_vars);
  printf ("Total number of categories: %d\n", cat->n_cats_total);

  printf ("\nReverse variable map:\n");

  for (v = 0 ; v < cat->n_cats_total; ++v)
    printf ("%d ", cat->reverse_variable_map[v]);
  printf ("\n");
}
#endif



static struct value_node *
lookup_value (const struct hmap *map, const struct variable *var, const union value *val)
{
  struct value_node *foo;
  unsigned int width = var_get_width (var);
  size_t hash = value_hash (val, width, 0);

  HMAP_FOR_EACH_WITH_HASH (foo, struct value_node, node, hash, map)
    {
      if (value_equal (val, &foo->value, width))
        break;

      fprintf (stderr, "Warning: Hash table collision\n");
    }

  return foo;
}


struct categoricals *
categoricals_create (const struct variable *const *v, size_t n_vars,
                     const struct variable *wv, enum mv_class exclude,
                     user_data_create_func *udf,
                     update_func *update, void *aux
                     )
{
  size_t i;
  struct categoricals *cat = xmalloc (sizeof *cat);
  
  cat->n_vp = n_vars;
  cat->wv = wv;
  cat->n_cats_total = 0;
  cat->n_vars = 0;
  cat->reverse_variable_map = NULL;
  cat->pool = pool_create ();
  cat->exclude = exclude;
  cat->update = update;
  cat->update_aux = aux;
  cat->user_data_create = udf;

  cat->vp = pool_calloc (cat->pool, cat->n_vp, sizeof *cat->vp);

  for (i = 0 ; i < cat->n_vp; ++i)
    {
      hmap_init (&cat->vp[i].map);
      cat->vp[i].var = v[i];
    }

  return cat;
}



void
categoricals_update (struct categoricals *cat, const struct ccase *c)
{
  size_t i;
  
  const double weight = cat->wv ? case_data (c, cat->wv)->f : 1.0;

  assert (NULL == cat->reverse_variable_map);

  for (i = 0 ; i < cat->n_vp; ++i)
    {
      const struct variable *var = cat->vp[i].var;
      unsigned int width = var_get_width (var);
      const union value *val = case_data (c, var);
      size_t hash;
      struct value_node *node ;

      if ( var_is_value_missing (var, val, cat->exclude))
        continue;

      hash = value_hash (val, width, 0);
      node = lookup_value (&cat->vp[i].map, var, val);

      if ( NULL == node)
        {
          node = pool_malloc (cat->pool, sizeof *node);

          value_init (&node->value, width);
          value_copy (&node->value, val, width);
          node->cc = 0.0;

          hmap_insert (&cat->vp[i].map, &node->node,  hash);
          cat->n_cats_total++;
          
          if ( 0 == cat->vp[i].n_cats)
            cat->n_vars++;

          node->subscript = cat->vp[i].n_cats++ ;

          if ( cat->user_data_create )
            node->user_data = cat->user_data_create ();
        }

      node->cc += weight;
      cat->vp[i].cc += weight;

      if ( cat->update)
        cat->update (node->user_data, cat->wv, var, c, cat->update_aux);
    }
}

/* Return the number of categories (distinct values) for variable N */
size_t
categoricals_n_count (const struct categoricals *cat, size_t n)
{
  return hmap_count (&cat->vp[n].map);
}


/* Return the total number of categories */
size_t
categoricals_total (const struct categoricals *cat)
{
  return cat->n_cats_total;
}


/* This function must be called *before* any call to categoricals_get_*_by subscript an
 *after* all calls to categoricals_update */
void
categoricals_done (struct categoricals *cat)
{
  /* Implementation Note: Whilst this function is O(n) in cat->n_cats_total, in most
     uses it will be more efficient that using a tree based structure, since it
     is called only once, and means that subsequent lookups will be O(1).

     1 call of O(n) + 10^9 calls of O(1) is better than 10^9 calls of O(log n).
  */
  int v;
  int idx = 0;
  cat->reverse_variable_map = pool_calloc (cat->pool,
                                           cat->n_cats_total,
                                           sizeof *cat->reverse_variable_map);
  
  for (v = 0 ; v < cat->n_vp; ++v)
    {
      int i;
      struct var_params *vp = &cat->vp[v];
      int n_cats_total = categoricals_n_count (cat, v);
      struct hmap_node *node ;

      vp->reverse_value_map = pool_calloc (cat->pool, n_cats_total, sizeof *vp->reverse_value_map);

      vp->base_subscript = idx;

      for (node = hmap_first (&vp->map); node; node = hmap_next (&vp->map, node))
        {
          const struct value_node *vn = HMAP_DATA (node, struct value_node, node);
          vp->reverse_value_map[vn->subscript] = vn;
        }

      /* Populate the reverse variable map.
       */
      for (i = 0; i < vp->n_cats; ++i)
        cat->reverse_variable_map[idx++] = v;
    }

  assert (cat->n_vars <= cat->n_vp);
}


static int
reverse_variable_lookup (const struct categoricals *cat, int subscript)
{
  assert (cat->reverse_variable_map);
  assert (subscript >= 0);
  assert (subscript < cat->n_cats_total);

  return cat->reverse_variable_map[subscript];
}


/* Return the categorical variable corresponding to SUBSCRIPT */
const struct variable *
categoricals_get_variable_by_subscript (const struct categoricals *cat, int subscript)
{
  int index = reverse_variable_lookup (cat, subscript);

  return cat->vp[index].var;
}

/* Return the value corresponding to SUBSCRIPT */
const union value *
categoricals_get_value_by_subscript (const struct categoricals *cat, int subscript)
{
  int vindex = reverse_variable_lookup (cat, subscript);
  const struct var_params *vp = &cat->vp[vindex];
  const struct value_node *vn = vp->reverse_value_map [subscript - vp->base_subscript];

  return &vn->value;
}


double
categoricals_get_weight_by_subscript (const struct categoricals *cat, int subscript)
{
  int vindex = reverse_variable_lookup (cat, subscript);
  const struct var_params *vp = &cat->vp[vindex];

  return vp->cc;
}

double
categoricals_get_sum_by_subscript (const struct categoricals *cat, int subscript)
{
  int vindex = reverse_variable_lookup (cat, subscript);
  const struct var_params *vp = &cat->vp[vindex];

  const struct value_node *vn = vp->reverse_value_map [subscript - vp->base_subscript];
  return vn->cc;
}


/* Returns unity if the value in case C at SUBSCRIPT is equal to the category
   for that subscript */
double
categoricals_get_binary_by_subscript (const struct categoricals *cat, int subscript,
                                      const struct ccase *c)
{
  const struct variable *var = categoricals_get_variable_by_subscript (cat, subscript);
  int width = var_get_width (var);

  const union value *val = case_data (c, var);

  return value_equal (val, categoricals_get_value_by_subscript (cat, subscript), width);
}


size_t
categoricals_get_n_variables (const struct categoricals *cat)
{
  return cat->n_vars;
}



void *
categoricals_get_user_data_by_subscript (const struct categoricals *cat, int subscript)
{
  int vindex = reverse_variable_lookup (cat, subscript);
  const struct var_params *vp = &cat->vp[vindex];

  const struct value_node *vn = vp->reverse_value_map [subscript - vp->base_subscript];
  return vn->user_data;
}