-/*
- * $Id: relevance.c,v 1.2 2006-12-20 22:18:33 adam Exp $
- */
+/* This file is part of Pazpar2.
+ Copyright (C) 2006-2009 Index Data
+
+Pazpar2 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 2, or (at your option) any later
+version.
+
+Pazpar2 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, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-#include <ctype.h>
+*/
+
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <assert.h>
#include <math.h>
#include <stdlib.h>
{
int *doc_frequency_vec;
int vec_len;
- struct word_trie *wt;
+ struct word_entry *entries;
+ pp2_charset_t pct;
NMEM nmem;
};
-// We use this data structure to recognize terms in input records,
-// and map them to record term vectors for counting.
-struct word_trie
-{
- struct
- {
- struct word_trie *child;
- int termno;
- } list[26];
+
+struct word_entry {
+ const char *norm_str;
+ int termno;
+ struct word_entry *next;
};
-static struct word_trie *create_word_trie_node(NMEM nmem)
+static void add_word_entry(NMEM nmem,
+ struct word_entry **entries,
+ const char *norm_str,
+ int term_no)
{
- struct word_trie *res = nmem_malloc(nmem, sizeof(struct word_trie));
- int i;
- for (i = 0; i < 26; i++)
+ struct word_entry *ne = nmem_malloc(nmem, sizeof(*ne));
+ ne->norm_str = nmem_strdup(nmem, norm_str);
+ ne->termno = term_no;
+
+ ne->next = *entries;
+ *entries = ne;
+}
+
+
+int word_entry_match(struct word_entry *entries, const char *norm_str)
+{
+ for (; entries; entries = entries->next)
{
- res->list[i].child = 0;
- res->list[i].termno = -1;
+ if (!strcmp(norm_str, entries->norm_str))
+ return entries->termno;
}
- return res;
+ return 0;
}
-static void word_trie_addterm(NMEM nmem, struct word_trie *n, const char *term, int num)
+static struct word_entry *build_word_entries(pp2_charset_t pct, NMEM nmem,
+ const char **terms)
{
- while (*term) {
- int c = tolower(*term);
- if (c < 'a' || c > 'z')
- term++;
- else
- {
- c -= 'a';
- if (!*(++term))
- n->list[c].termno = num;
- else
- {
- if (!n->list[c].child)
- {
- struct word_trie *new = create_word_trie_node(nmem);
- n->list[c].child = new;
- }
- word_trie_addterm(nmem, n->list[c].child, term, num);
- }
- break;
- }
+ int termno = 1; /* >0 signals THERE is an entry */
+ struct word_entry *entries = 0;
+ const char **p = terms;
+
+ for (; *p; p++)
+ {
+ pp2_relevance_token_t prt = pp2_relevance_tokenize(pct, *p, 0);
+ const char *norm_str;
+
+ while ((norm_str = pp2_relevance_token_next(prt)))
+ add_word_entry(nmem, &entries, norm_str, termno);
+
+ pp2_relevance_token_destroy(prt);
+
+ termno++;
}
+ return entries;
}
-#define raw_char(c) (((c) >= 'a' && (c) <= 'z') ? (c) - 'a' : -1)
-
-static int word_trie_match(struct word_trie *t, const char *word, int len, int *skipped)
+void relevance_countwords(struct relevance *r, struct record_cluster *cluster,
+ const char *words, int multiplier, const char *name)
{
- int c = raw_char(tolower(*word));
+ pp2_relevance_token_t prt = pp2_relevance_tokenize(r->pct, words, 0);
+ int *mult = cluster->term_frequency_vec_tmp;
+ const char *norm_str;
+ int i, length = 0;
- if (!len)
- return 0;
+ for (i = 1; i < r->vec_len; i++)
+ mult[i] = 0;
- word++; len--;
- (*skipped)++;
- if (!len || raw_char(*word) < 0)
- {
- if (t->list[c].termno > 0)
- return t->list[c].termno;
- else
- return 0;
- }
- else
+ while ((norm_str = pp2_relevance_token_next(prt)))
{
- if (t->list[c].child)
+ int res = word_entry_match(r->entries, norm_str);
+ if (res)
{
- return word_trie_match(t->list[c].child, word, len, skipped);
+ assert(res < r->vec_len);
+ mult[res] += multiplier;
}
- else
- return 0;
+ length++;
}
-}
-
-
-static struct word_trie *build_word_trie(NMEM nmem, const char **terms)
-{
- struct word_trie *res = create_word_trie_node(nmem);
- const char **p;
- int i;
+ for (i = 1; i < r->vec_len; i++)
+ {
+ if (length > 0) /* only add if non-empty */
+ cluster->term_frequency_vecf[i] += (double) mult[i] / length;
+ cluster->term_frequency_vec[i] += mult[i];
+ }
- for (i = 1, p = terms; *p; p++, i++)
- word_trie_addterm(nmem, res, *p, i);
- return res;
+ cluster->term_frequency_vec[0] += length;
+ pp2_relevance_token_destroy(prt);
}
-struct relevance *relevance_create(NMEM nmem, const char **terms, int numrecs)
+struct relevance *relevance_create(pp2_charset_t pct,
+ NMEM nmem, const char **terms)
{
struct relevance *res = nmem_malloc(nmem, sizeof(struct relevance));
const char **p;
;
res->vec_len = ++i;
res->doc_frequency_vec = nmem_malloc(nmem, res->vec_len * sizeof(int));
- bzero(res->doc_frequency_vec, res->vec_len * sizeof(int));
+ memset(res->doc_frequency_vec, 0, res->vec_len * sizeof(int));
res->nmem = nmem;
- res->wt = build_word_trie(nmem, terms);
+ res->entries = build_word_entries(pct, nmem, terms);
+ res->pct = pct;
return res;
}
-void relevance_newrec(struct relevance *r, struct record *rec)
+void relevance_newrec(struct relevance *r, struct record_cluster *rec)
{
if (!rec->term_frequency_vec)
{
- rec->term_frequency_vec = nmem_malloc(r->nmem, r->vec_len * sizeof(int));
- bzero(rec->term_frequency_vec, r->vec_len * sizeof(int));
+ int i;
+
+ // term frequency [1,..] . [0] is total length of all fields
+ rec->term_frequency_vec =
+ nmem_malloc(r->nmem,
+ r->vec_len * sizeof(*rec->term_frequency_vec));
+ for (i = 0; i < r->vec_len; i++)
+ rec->term_frequency_vec[i] = 0;
+
+ // term frequency divided by length of field [1,...]
+ rec->term_frequency_vecf =
+ nmem_malloc(r->nmem,
+ r->vec_len * sizeof(*rec->term_frequency_vecf));
+ for (i = 0; i < r->vec_len; i++)
+ rec->term_frequency_vecf[i] = 0.0;
+
+ // for relevance_countwords (so we don't have to xmalloc/xfree)
+ rec->term_frequency_vec_tmp =
+ nmem_malloc(r->nmem,
+ r->vec_len * sizeof(*rec->term_frequency_vec_tmp));
}
}
-// FIXME. The definition of a word is crude here.. should support
-// some form of localization mechanism?
-void relevance_countwords(struct relevance *r, struct record *head,
- const char *words, int len, int multiplier)
-{
- while (len)
- {
- char c;
- int res;
- int skipped;
- while (len && (c = raw_char(tolower(*words))) < 0)
- {
- words++;
- len--;
- }
- if (!len)
- return;
- skipped = 0;
- if ((res = word_trie_match(r->wt, words, len, &skipped)))
- {
- words += skipped;
- len -= skipped;
- head->term_frequency_vec[res] += multiplier;
- }
- else
- {
- while (len && (c = raw_char(tolower(*words))) >= 0)
- {
- words++;
- len--;
- }
- }
- head->term_frequency_vec[0]++;
- }
-}
-
-void relevance_donerecord(struct relevance *r, struct record *head)
+void relevance_donerecord(struct relevance *r, struct record_cluster *cluster)
{
int i;
for (i = 1; i < r->vec_len; i++)
- if (head->term_frequency_vec[i] > 0)
+ if (cluster->term_frequency_vec[i] > 0)
r->doc_frequency_vec[i]++;
r->doc_frequency_vec[0]++;
}
-#ifdef FLOAT_REL
-static int comp(const void *p1, const void *p2)
-{
- float res;
- struct record **r1 = (struct record **) p1;
- struct record **r2 = (struct record **) p2;
- res = (*r2)->relevance - (*r1)->relevance;
- if (res > 0)
- return 1;
- else if (res < 0)
- return -1;
- else
- return 0;
-}
-#else
-static int comp(const void *p1, const void *p2)
-{
- struct record **r1 = (struct record **) p1;
- struct record **r2 = (struct record **) p2;
- return (*r2)->relevance - (*r1)->relevance;
-}
-#endif
-
-// Prepare for a relevance-sorted read of up to num entries
+// Prepare for a relevance-sorted read
void relevance_prepare_read(struct relevance *rel, struct reclist *reclist)
{
int i;
float *idfvec = xmalloc(rel->vec_len * sizeof(float));
+ reclist_rewind(reclist);
// Calculate document frequency vector for each term.
for (i = 1; i < rel->vec_len; i++)
{
if (!rel->doc_frequency_vec[i])
idfvec[i] = 0;
else
- idfvec[i] = log((float) rel->doc_frequency_vec[0] / rel->doc_frequency_vec[i]);
+ {
+ // This conditional may be terribly wrong
+ // It was there to address the situation where vec[0] == vec[i]
+ // which leads to idfvec[i] == 0... not sure about this
+ // Traditional TF-IDF may assume that a word that occurs in every
+ // record is irrelevant, but this is actually something we will
+ // see a lot
+ if ((idfvec[i] = log((float) rel->doc_frequency_vec[0] /
+ rel->doc_frequency_vec[i])) < 0.0000001)
+ idfvec[i] = 1;
+ }
}
// Calculate relevance for each document
- for (i = 0; i < reclist->num_records; i++)
+
+ while (1)
{
int t;
- struct record *rec = reclist->flatlist[i];
- float relevance;
- relevance = 0;
+ int relevance = 0;
+ struct record_cluster *rec = reclist_read_record(reclist);
+ if (!rec)
+ break;
for (t = 1; t < rel->vec_len; t++)
{
float termfreq;
- if (!rec->term_frequency_vec[0])
- break;
- termfreq = (float) rec->term_frequency_vec[t] / rec->term_frequency_vec[0];
- relevance += termfreq * idfvec[t];
+#if 1
+ termfreq = (float) rec->term_frequency_vecf[t];
+#else
+ if (rec->term_frequency_vec[0])
+ {
+ termfreq = (float)
+ rec->term_frequency_vec[t] / rec->term_frequency_vec[0] ;
+ }
+ else
+ termfreq = 0.0;
+#endif
+ relevance += 100000 * (termfreq * idfvec[t] + 0.0000005);
}
- rec->relevance = (int) (relevance * 100000);
+ rec->relevance = relevance;
}
- qsort(reclist->flatlist, reclist->num_records, sizeof(struct record*), comp);
- reclist->pointer = 0;
+ reclist_rewind(reclist);
xfree(idfvec);
}
/*
* Local variables:
* c-basic-offset: 4
+ * c-file-style: "Stroustrup"
* indent-tabs-mode: nil
* End:
* vim: shiftwidth=4 tabstop=8 expandtab
*/
+
projects / pazpar2-moved-to-github.git / blobdiff