-/*
- * $Id: relevance.c,v 1.7 2007-01-10 10:04:23 adam Exp $
+/* $Id: relevance.c,v 1.11 2007-05-01 05:04:53 quinn Exp $
+ Copyright (c) 2006-2007, Index Data.
+
+This file is part of Pazpar2.
+
+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 Pazpar2; see the file LICENSE. If not, write to the
+Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA.
*/
#include <ctype.h>
static void word_trie_addterm(NMEM nmem, struct word_trie *n, const char *term, int num)
{
+
while (*term) {
int c = tolower(*term);
if (c < 'a' || c > 'z')
r->doc_frequency_vec[0]++;
}
+#ifdef GAGA
#ifdef FLOAT_REL
static int comp(const void *p1, const void *p2)
{
return (*r2)->relevance - (*r1)->relevance;
}
#endif
+#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;
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++)
}
rec->relevance = (int) (relevance * 100000);
}
+#ifdef GAGA
qsort(reclist->flatlist, reclist->num_records, sizeof(struct record*), comp);
+#endif
reclist->pointer = 0;
xfree(idfvec);
}