source: trunk/gsdl/src/mgpp/text/mg_weights_build.cpp@ 860

/**************************************************************************
 *
 * mg_weights_build.cpp -- Program to build the document weights file
 * Copyright (C) 1999  Rodger McNab
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id: mg_weights_build.cpp 860 2000-01-18 03:53:24Z rjmcnab $
 *
 **************************************************************************/

#include "sysfuncs.h"
#include "memlib.h"
#include "messages.h"
#include "local_strings.h"
#include "bitio_gen.h"
#include "bitio_m_stdio.h"

#include "mg_files.h"
#include "locallib.h"
#include "invf.h"
// #include "WordData.h"
#include "UCArray.h"
#include "FIvfLevelInfo.h"
#include "FragLevelConvert.h"

#if defined(GSDL_USE_OBJECTSPACE)
#  include <ospace\std\map>
#elif defined(GSDL_USE_STL_H)
#  include <map.h>
#else
#  include <map>
#endif


/*
   $Log$
   Revision 1.2  2000/01/18 03:53:24  rjmcnab
   Fixed a couple of bugs and made building silent if needed.

   Revision 1.1  2000/01/14 02:26:21  sjboddie
   Rodgers new C++ mg

   Revision 1.1  1999/10/11 02:58:06  cs025
   Base install of MG-PP

   Revision 1.1  1999/08/10 21:18:16  sjboddie
   renamed mg-1.3d directory mg

   Revision 1.2  1998/11/25 07:55:49  rjmcnab

   Modified mg to that you can specify the stemmer you want
   to use via a command line option. You specify it to
   mg_passes during the build process. The number of the
   stemmer that you used is stored within the inverted
   dictionary header and the stemmed dictionary header so
   the correct stemmer is used in later stages of building
   and querying.

   Revision 1.1  1998/11/17 09:35:22  rjmcnab
   *** empty log message ***

   * Revision 1.4  1994/11/29  00:32:05  tes
   * Committing the new merged files and changes.
   *
   * Revision 1.3  1994/10/20  03:57:00  tes
   * I have rewritten the boolean query optimiser and abstracted out the
   * components of the boolean query.
   *
   * Revision 1.2  1994/09/20  04:41:55  tes
   * For version 1.1
   *
 */

#define MAXBITS (sizeof(unsigned long) * 8)

struct WBTagPtr {
  unsigned long tagNum;
  unsigned long tagPtr;
  unsigned long fragOccur;
  
  WBTagPtr () {
    tagNum = 0;
    tagPtr = 0;
    fragOccur = 0;
  }
};

// maps tags to tag information
typedef map<UCArray, WBTagPtr, DictLTUCArray> WBTagDict;

typedef vector<float> Weights;


static void ReadTagDict (const invf_dict_header &idh,
             FILE *dictFile,
             FILE *invfIdxFile,
             WBTagDict &tagDict) {
  tagDict.erase (tagDict.begin(), tagDict.end());

  // seek to the start of the tag information
  fseek (dictFile, idh.tag_dict_start, SEEK_SET);
  fseek (invfIdxFile, sizeof(unsigned long) +
     idh.word_dict_size*sizeof(unsigned long), SEEK_SET);
  
  unsigned long tagNum;
  unsigned long tagPtr;
  dict_el thisEl;
  for (tagNum = 0; tagNum < idh.tag_dict_size; tagNum++) {
    thisEl.Read (dictFile);
    ReadUL (invfIdxFile, tagPtr);
    tagDict[thisEl.el].tagNum = tagNum;
    tagDict[thisEl.el].tagPtr = tagPtr;
    tagDict[thisEl.el].fragOccur = thisEl.frag_occur;
  }
}

static void AddWeight (Weights &w,
               unsigned long levelDocNum,
               unsigned long termFreq,
               float idf) {
  double weight = termFreq * idf;
  w[levelDocNum-1] += weight * weight;
}

static void GenerateLevelWeights (const invf_dict_header &idh,
                  const invf_file_header &ifh,
                  unsigned long numLevelDocs,
                  unsigned long levelNum,
                  FILE *dictFile,
                  FILE *invfFile,
                  FILE *invfIdxFile,
                  const FragLevelConvert &fragLevelConvert,
                  Weights &w) {
  // pre-allocate the right number of weights
  w.erase (w.begin(), w.end());
  w.insert (w.end(), (Weights::size_type)numLevelDocs, (float)0.0);

  double logN = log ((double) numLevelDocs);

  // reset the files
  fseek (dictFile, idh.word_dict_start, SEEK_SET);
  fseek (invfIdxFile, sizeof (unsigned long), SEEK_SET);
  
  // process each word adding its contributions to the document weights
  unsigned long wordNum;
  unsigned long wordStart;
  word_dict_el wordEl;
  wordEl.SetNumLevels (idh.num_levels);
  for (wordNum=0; wordNum<idh.word_dict_size; wordNum++) {
#ifndef SILENT
    // give a little feedback every 4096 words
    if ((wordNum & 0xfff) == 0) fprintf (stderr, ".");
#endif
    
    wordEl.Read (dictFile, idh.num_levels);
    ReadUL (invfIdxFile, wordStart);

    float idf = logN - log ((double) wordEl.levelFreqs[levelNum]);

    // seek to the appropriate place in the inverted file
    fseek (invfFile, wordStart, SEEK_SET);
    stdio_bitio_buffer buffer (invfFile);
    
    unsigned long B = BIO_Bblock_Init (idh.num_frags, wordEl.frag_occur);
    unsigned long fragNum = 0;
    unsigned long levelDocNum = 0;
    unsigned long lastLevelDocNum = 0;
    unsigned long termFreq = 0;
    unsigned long checkLevelFreq = 0;
    
    unsigned long count, i;
    for (i=0; i<wordEl.frag_occur; i++) {
      fragNum += buffer.bblock_decode (B, NULL);
      if (!ifh.word_level_index) count = buffer.gamma_decode (NULL);
      else count = 1;

      if (fragNum > idh.num_frags)
    FatalError (1, "fragNum = %d, "
            "number of fragments = %d\n"
            "wordNum = %d\n"
            "i = %d, frag_occur = %d\n",
            fragNum, idh.num_frags, wordNum, i, wordEl.frag_occur);

      if (!fragLevelConvert.FragToLevel (fragNum, levelDocNum))
    FatalError (1, "could not convert fragment number %d", fragNum);

      if (levelDocNum == 0 || levelDocNum > numLevelDocs)
    FatalError (1, "bad level document number %d", levelDocNum);
      
      if (levelDocNum != lastLevelDocNum) {
    // new level document
    if (lastLevelDocNum > 0) {
      AddWeight (w, lastLevelDocNum, termFreq, idf);
      checkLevelFreq++;
    }
    lastLevelDocNum = levelDocNum;
    termFreq = 0;
      }
      termFreq += count;
    }

    if (lastLevelDocNum > 0) {
      AddWeight (w, lastLevelDocNum, termFreq, idf);
      checkLevelFreq++;
    }

    if (checkLevelFreq != wordEl.levelFreqs[levelNum]) {
      cerr << "bad level freq " << checkLevelFreq << " != "
       << wordEl.levelFreqs[levelNum] << ", word \""
       << wordEl.el << "\" (" << wordNum << ")\n";
      exit (1);
    }
    
    buffer.done();
  }

  if (w.size() != numLevelDocs) 
    FatalError (1, "wrong number of weights created %d != %d",
        w.size(), numLevelDocs);
}

static void WriteExactWeights (FILE *weightsFile,
                   unsigned long &diskPtr,
                   const Weights &w) {
  diskPtr = ftell(weightsFile);

  Weights::const_iterator here = w.begin();
  Weights::const_iterator end = w.end();
  while (here != end) {
//      cout << *here << "\n";
    WriteF (weightsFile, *here);
    here++;
  }
}

static void WriteApproxWeights (FILE *approxWeightsFile,
                unsigned long &diskPtr,
                const Weights &w,
                unsigned char bits) {
  diskPtr = ftell(approxWeightsFile);

  // calculate L, U and B
  double L = 1e300;
  double U = 0;
  float wgt;
  Weights::const_iterator here = w.begin();
  Weights::const_iterator end = w.end();
  while (here != end) {
    wgt = sqrt (*here);
    if (wgt > U) U = wgt;
    if (wgt > 0 && wgt < L) L = wgt;
    here++;
  }

  double B = pow (U / L, pow (2.0, -(double) bits));

#ifndef SILENT
  fprintf (stderr, "L = %f\n", L);
  fprintf (stderr, "U = %f\n", U);
  fprintf (stderr, "B = %f\n", B);
#endif
  
  WriteUC (approxWeightsFile, bits);
  WriteD (approxWeightsFile, L);
  WriteD (approxWeightsFile, B);
  

  unsigned long max = (bits == 32) ? 0xffffffff : (1 << bits) - 1;;
  unsigned long i=0, buf=0, pos=0;
  here = w.begin();
  end = w.end();
  while (here != end) {
    unsigned long fx;
    wgt = sqrt (*here);
    if (wgt == 0) {
      wgt = L;
#ifndef SILENT
      Message ("Warning: Document %d had a weight of 0.", i);
#endif
    }
    fx = (unsigned long) floor (log (wgt / L) / log (B));

    if (fx > max) fx = max;

    buf |= (fx << pos);
    pos += bits;

    if (pos >= MAXBITS) {
      WriteUL (approxWeightsFile, buf);
      buf = fx >> (bits - (pos - MAXBITS));
      pos = pos - MAXBITS;
    }

    here++; i++;
  }

  // write out the last bits
  if (pos > 0) WriteUL (approxWeightsFile, buf);
}

int main (int argc, char **argv) {
  unsigned char bits = 8;
  char *filename = "";
  int ch;
  opterr = 0;
  msg_prefix = argv[0];

  while ((ch = getopt (argc, argv, "f:d:b:h")) != -1) {
    switch (ch) {
    case 'f':       // input file
      filename = optarg;
      break;
    case 'd':
      set_basepath (optarg);
      break;
    case 'b':
      bits = atoi (optarg);
      if (bits > 32) {
    fprintf (stderr, "b may only take values 0-32\n");
    exit (1);
      }
      break;
    case 'h':
    case '?':
      fprintf (stderr, "usage: %s [-f input_file]"
           "[-d data directory] [-b bits] [-h]\n", argv[0]);
      exit (1);
    }
  }

  
  // open the dictionary
  FILE *dictFile = open_file (filename, INVF_DICT_SUFFIX, "rb",
                  MAGIC_STEM_BUILD, MG_ABORT);
  invf_dict_header idh;
  idh.Read (dictFile);

  // open the inverted file
  FILE *invfFile = open_file (filename, INVF_SUFFIX, "rb",
            MAGIC_INVF, MG_ABORT);
  invf_file_header ifh;
  ifh.Read (invfFile);
  if (ifh.skip_mode != SKIP_MODE_NO_SKIPS)
    FatalError (1, "The invf file contains skips. Unable to create weights.");

  // open the inverted index file
  FILE *invfIdxFile = open_file (filename, INVF_IDX_SUFFIX, "rb",
                 MAGIC_INVI, MG_ABORT);
  
  // read the level information
  FILE *levelFile = open_file (filename, INVF_LEVEL_SUFFIX, "rb",
                   MAGIC_INVF_LEVELS, MG_ABORT);
  FIvfLevel ivfLevel;
  ivfLevel.Read (levelFile);
  fclose (levelFile);

  // read in the tag dictionary and inverted file pointers
  WBTagDict tagDict;
  ReadTagDict (idh, dictFile, invfIdxFile, tagDict);

  
  // create the weights file
  FILE *weightsFile = create_file (filename, WEIGHTS_SUFFIX, "wb",
                   MAGIC_WGHT, MG_ABORT);

  // create the approx weights file
  FILE *approxWeightsFile = create_file (filename, APPROX_WEIGHTS_SUFFIX, "wb",
                     MAGIC_WGHT_APPROX, MG_ABORT);

  
  // create weights for each document level
  FragLevelConvert fragLevelConvert;
  Weights w;
  IvfLevelInfoMap::iterator levelHere = ivfLevel.levelInfo.begin();
  IvfLevelInfoMap::iterator levelEnd = ivfLevel.levelInfo.end();
  unsigned long levelNum = 0;
  while (levelHere != levelEnd) {
    const UCArray &levelName = (*levelHere).first;
    
    // read the tag information about this level
    fragLevelConvert.Read(invfFile, tagDict[levelName].tagPtr,
              idh.num_frags, tagDict[levelName].fragOccur);
    
    // create the weights for this level
    GenerateLevelWeights (idh, ifh, tagDict[levelName].fragOccur,
              levelNum, dictFile, invfFile, invfIdxFile,
              fragLevelConvert, w);

    // write out the exact weights
    WriteExactWeights (weightsFile,
               (*levelHere).second.exactWeightsDiskPtr,
               w);
    
    // write out the approximate weights
    WriteApproxWeights (approxWeightsFile,
            (*levelHere).second.approxWeightsDiskPtr,
            w, bits);
    
    levelHere++; levelNum++;
  }
  

  // close input files
  fclose (dictFile);
  fclose (invfFile);
  fclose (invfIdxFile);

  // update the level information
  levelFile = create_file (filename, INVF_LEVEL_SUFFIX, "wb",
               MAGIC_INVF_LEVELS, MG_ABORT);
  ivfLevel.Write (levelFile);
  fclose (levelFile);

  // close output files
  fclose (weightsFile);
  fclose (approxWeightsFile);


  return 0;
}