/*! \file lib/clipper_stats.h
    Header file for clipper helper functions
*/
//C Copyright (C) 2000-2006 Kevin Cowtan and University of York
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#ifndef CLIPPER_STATS
#define CLIPPER_STATS


#include "clipper_types.h"


namespace clipper
{

  //! Range - upper and lower bounds of some type
  template<class T = ftype> class Range
  {
  public:
    //! null constructor
    inline Range() { lmin = 999999999; lmax = -999999999; }
    //! constructor
    inline Range( const T& min, const T& max ) { lmin = min; lmax = max; }
    inline const T& min() const { return lmin; } //!< minimum value
    inline const T& max() const { return lmax; } //!< maximum value
    inline T range() const { return lmax-lmin; } //!< range = max - min
    //! update limits to include a new datum
    inline void include( const T& datum )
      { lmin = (datum<lmin)?datum:lmin; lmax = (datum>lmax)?datum:lmax; }
    //! test if data is within limits ( min <= datum <= max )
    inline bool contains( const T& datum ) const
      { return ( datum >= lmin && datum <= lmax ); }
    //! truncate data to be within range
    inline T truncate( const T& datum ) const
      { return Util::bound( lmin, datum, lmax ); }
  private:
    T lmin, lmax;
  };

  //! Range sampling: discrete sampling of a real range.
  class Range_sampling : public Range<ftype>
  {
  public:
    //! null constructor
    inline Range_sampling() : n_(0) {}
    //! constructor: from number of samplings
    inline Range_sampling( const int& n ) : n_(n) {}
    //! constructor: from range and number of samplings
    inline Range_sampling( const Range<ftype>& range, const int& n ) :
      Range<ftype>( range ), n_(n) {}
    //! return fractional posn in counting range from x-value (0..n)
    inline ftype indexf( const ftype& x ) const
      { return ftype(size())*(x-min())/range(); }
    //! return x-value  (0..n) from fractional posn in counting range
    inline ftype x( const ftype& i ) const
      { return range()*i/ftype(size())+min(); }
    //! return nearest index to particular x-value
    inline int index( const ftype& x ) const { return Util::intf( indexf(x) ); }
    //! return nearest index to particular x-value (bounded 0...n-1)
    inline int index_bounded( const ftype& x ) const
      { return Util::bound( 0, Util::intf( indexf(x) ), size()-1 ); }
    //! return x-value corresponding to centre of i'th range
    inline ftype x( const int& i ) const     { return x( ftype(i)+0.5 ); }
    //! return x-value corresponding to bottom of i'th range
    inline ftype x_min( const int& i ) const { return x( ftype(i)     ); }
    //! return x-value corresponding to top of i'th range
    inline ftype x_max( const int& i ) const { return x( ftype(i)+1.0 ); }
    //! return number of samplings in range
    inline int size() const { return n_; }
  private:
    int n_;
  };

  //! General histogram class
  /*! This class is used to accumulate and access a histogram of
    values spread over a specified range. On storing data or
    retrieving by interpolation the range is checked. */
  class Histogram : public Range_sampling
  {
  public:
    //! null constructor
    Histogram() {}
    //! constructor: from range and sampling
    Histogram( const Range<ftype>& range, const int& n ) :
      Range_sampling( range, n ), data( n, 0.0 ) {}
    //! add value to histogram (if it is in range)
    void accumulate( const ftype& x )
      { if ( contains(x) ) data[ index_bounded(x) ] += 1.0; }
    //! add specified value to histogram (if it is in range)
    void accumulate( const ftype& x, const ftype& w )
      { if ( contains(x) ) data[ index_bounded(x) ] += w; }
    //! return sum of whole histogram
    ftype sum() const;
    //! return value at index in histogram (Note: no bound check on i)
    inline const ftype& y( const int& i ) const { return data[i]; }
    //! return value at interpolated position in histogram
    ftype y( const ftype& x ) const;
    //! add the contents of two histograms (size must match)
    const Histogram& operator += ( const Histogram& h );
    // inherited functions listed for documentation purposes
    //-- inline ftype x( const int& i ) const;
    //-- inline ftype x_min( const int& i ) const;
    //-- inline ftype x_max( const int& i ) const;
    //-- inline int size() const;
  private:
    std::vector<ftype> data;
  };


  //! Generic ordinal gernerator
  /*! This is a generic fast ordinal calculator. It is supplied with a
    list of values, from which it prepares a cumulative distribution
    function. This may the used to return the approximate fracitonal
    ordinal (in the range 0...1) for any given value from the
    distibution.

    The distibution may be initialised by providing a vector of values
    from the distribution, or by adding the values and calling
    prep_ordinal().

    This distribution may also be inverted. Generation of a value from
    an ordinal may be used for generating random values from a given
    distribution, or for histogram matching. */
  class Generic_ordinal
  {
  public:
    //! null constructor
    Generic_ordinal() {}
    //! constructor: from range and sampling
    Generic_ordinal( const Range<ftype>& range, const int& n )
      { init( range, n ); }
    //! initialiser: takes the source range and sampling
    void init( const Range<ftype>& range, const int num_ranges = 1000 );
    //! initialiser: takes the source distibution and a number of bins
    void init( const std::vector<ftype>& values, const int num_ranges = 1000 );
    //! return reflection ordinal
    ftype ordinal( const ftype& value ) const;

    //! accumulate values to build the distribution
    void accumulate( const ftype& value );
    //! accumulate values to build the distribution
    void accumulate( const ftype& value, const ftype& weight );
    //! generate the ordinal histogram
    void prep_ordinal();
    //! invert distribution to get value from ordinal
    void invert();

    //! DEPRECATED: initialiser: takes a number of bins for histogram
    void init( const int num_ranges = 1000 );
    //! DEPRECATED: add a value to the distribution (pass 1 of 2)
    void add_pass_1( const ftype& value );
    //! DEPRECATED: add a value to the distribution (pass 2 of 2)
    void add_pass_2( const ftype& value );
  protected:
    ftype nranges;            //!< number of ranges
    Range<ftype> range_;      //!< resolution range of data
    std::vector<ftype> hist;  //!< histogram of reflections vs resolution
  };



} // namespace clipper

#endif
