contrib/mul/vpdfl/vpdfl_gaussian_kernel_pdf_sampler.h

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// This is mul/vpdfl/vpdfl_gaussian_kernel_pdf_sampler.h
#ifndef vpdfl_gaussian_kernel_pdf_sampler_h
#define vpdfl_gaussian_kernel_pdf_sampler_h
#ifdef VCL_NEEDS_PRAGMA_INTERFACE
#pragma interface
#endif
//:
// \file
// \author Tim Cootes
// \brief Sampler class for gaussian kernel PDF.

#include <vcl_string.h>
#include <vnl/vnl_fwd.h>
#include <vnl/vnl_random.h>
#include <vpdfl/vpdfl_sampler_base.h>
class vpdfl_gaussian_kernel_pdf;

//=======================================================================

//: Samples from an axis aligned Gaussian PDF
class vpdfl_gaussian_kernel_pdf_sampler :public vpdfl_sampler_base
{
 protected:
  //: The random number generator
  vnl_random rng_; 
 public:

  // Dflt ctor
  vpdfl_gaussian_kernel_pdf_sampler();

  // Destructor
  virtual ~vpdfl_gaussian_kernel_pdf_sampler();

  //: Set model for which this is an instance
  // Error check that it is an axis gaussian.
  virtual void set_model(const vpdfl_pdf_base&);

  //: Draw random sample from j-th component of distribution
  void sample_component(vnl_vector<double>& x, int j);

  //: Draw random sample from distribution
  virtual void sample(vnl_vector<double>& x);

  //: Fill x with samples possibly chosen so as to represent the distribution
  //  Sample sequentially from each component.
  virtual void regular_samples(vcl_vector<vnl_vector<double> >& x);

  //: Reseeds the internal random number generator
  // To achieve quasi-random initialisation use;
  // \code
  // #include <vcl_ctime.h>
  // ..
  // sampler.reseed(vcl_time(0));
  // \endcode
  virtual void reseed(unsigned long);


  //: Return a reference to the pdf model
  // This is properly cast.
  const vpdfl_gaussian_kernel_pdf& gaussian_kernel_pdf() const;

  //: Name of the class
  virtual vcl_string is_a() const;

  //: Does the name of the class match the argument?
  virtual bool is_class(vcl_string const& s) const;

  //: Create a copy on the heap and return base class pointer
  virtual vpdfl_sampler_base* clone() const;
};

#endif // vpdfl_gaussian_kernel_pdf_sampler_h