SDBWithStats.h

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 1998 Pascal Vincent
// Copyright (C) 1999-2002 Pascal Vincent, Yoshua Bengio and University of Montreal
//

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
// 
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
// 
//  3. The name of the authors may not be used to endorse or promote
//     products derived from this software without specific prior written
//     permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
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// This file is part of the PLearn library. For more information on the PLearn
// library, go to the PLearn Web site at www.plearn.org


 

/* *******************************************************      
   * $Id: SDBWithStats.h,v 1.4 2004/03/03 14:11:01 tihocan Exp $
   * AUTHORS: Pascal Vincent
   * This file is part of the PLearn library.
   ******************************************************* */


#ifndef SDBWithStats_INC
#define SDBWithStats_INC

//#include "general.h"
#include "SimpleDB.h"
#include <map>

namespace PLearn {
using namespace std;

  class FieldStat
  {
    friend class SDBWithStats;

  protected:

    int nonmissing_; 
    int missing_;    

    double sum_;
    double sumsquare_;

    double min_;
    double max_;
    double mean_;
    double stddev_;

  public:

    map<string,int> symbolcount;
    mutable map<string,int> symbolid; 
    int nsymbols() { return (int)symbolcount.size(); }
    static int max_nsymbols; 

    FieldStat()
      :nonmissing_(0), missing_(0), 
      sum_(0.), sumsquare_(0), min_(FLT_MAX), max_(-FLT_MAX)
    {}

    int ntotal() const { return missing_+nonmissing_; }
    int missing() const { return missing_; }
    int nonmissing() const { return nonmissing_; }
    real mean() const { return real(mean_); }
    real stddev() const { return real(stddev_); }
    real min() const { return real(min_); }
    real max() const { return real(max_); }

    void updateString(const string& sym);
    void updateNumber(double d);
    void updateMissing()  { ++missing_; }

    void clear(); 
    void finalize(); 
  };

  class SDBWithStats: public SDB
  {
  public:
    vector<FieldStat> fieldstat;
    int nfields() { return (int)getSchema().size(); }
    string fieldname(int i) { return getSchema()[i].name; }

  public:
    SDBWithStats(string basename, string path=".", AccessType access = readwrite,
                 bool verbose=true);

    void forgetStats();
    void computeStats(unsigned int nrows);
    void computeStats() { computeStats(size()); }

    bool hasStats(); 
    void saveStats();
    void loadStats();

    FieldStat& getStat(int i);
    const FieldStat& getStat(int i) const;
    FieldStat& getStat(const string& fieldname);
    const FieldStat& getStat(const string& fieldname) const;
  };

} // end of namespace PLearn

#endif

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