fastgauss.h

快速高斯变换的程序

// File    : FastGauss.h
// Purpose : FAST GAUSS TRANSFORM interface
// Author  : Changjiang Yang
//
// $Revision: 0.99 $
// $Date	: Mon Jul  8 18:11:31 EDT 2002 $
//
// $Revision: 1.00 $
// $Date	: Wed Jan 29 16:05:21 EDT 2003 $
//
// $Revision: 1.01 $
// $Date	: Wed Apr 14 09:51:26 EDT 2004 $

#ifndef FAST_GAUSS_H
#define FAST_GAUSS_H

#include <mex.h>
//#include <malloc.h>

//interface for FastGauss:
class FastGauss{
private:
//------------------------------------------------------------------------------------//
	//	data structure
	// interface:
	int Dim;		//dimension of the points.
	int NSources;	//number of sources.
	int DWeights;	//dimension of weights.
	
	double *pSources;	//pointer to sources, (Dim*Nsources).
	double *pSigmas;	//pointer to sigmas, (Dim*Nsources).
	double *pWeights;	//pointer to weights, (DWeights*NSources).

	double bandwid;		//bandwidth
	double epsilon;		//desired precision.
	int pterms;			//number of truncation terms.

	// internal data:
	int pd;				//number of coefficients
	
	double *A_k;		//pointer to coefficients
	double *B_k;		//pointer to coefficients

	int K_N;
	double ratio_far;

	double *xc;
	int *xcind;			//center of the sources
	int *indx;
	int *xheads;
	int *xboxsz;
	int *bkindx;
	double rx2;



//---------------------------------------------------------------------------------------//	
	//	private functions

	int nchoosek(int n, int k);

	void TaylorExpansion(int d, int du, int p);	
	void Compute_C_k(int d, int p, double *C_k);
	void Compute_A_k(double *xc, double *C_k);
	void Compute_Centers(double *xc, double *x, int d, int n, int *ind, int K, int *bxsz);


	// K-centers algorithm
	double dkcenter(const int dim, const int n, const int K,
				const double *x, double *cn, int *cind);

	double dkcenter(const int dim, const int n, const int K,
				const double *x, int *cn, int *cind);

	double dkcenter(const int dim, const int n, const int K,
				const double *x, int *cn, int *cind, int *cnn);

	double dkcenter(const int dim, const int n, const int K,
				const double *x, int *cn, int *cind, 
				int *heads, int *boxsz, int *nind);

	inline float sdist(const int d, const float *x, const float *y);
	inline double ddist(const int d, const double *x, const double *y);

	// Some functions of Intel Math Kernel Library.
	// Implemented for the 
	void dcopy(const int d, const double *x, double *y);
	int idmax(int n, double *x);

//---------------------------------------------------------------------------------------//	
	//	public functions
public:
	
	//constructors
	FastGauss(int dim, double *u, int du, double *x, int ns, 
					double h, int p, int K, double e);
	//destructor
	~FastGauss();

	void Compute_v_i(double *y, const int mt, double *v_i);

	void *operator new[] (size_t s){ return mxMalloc(s);}
	void operator delete[] (void* mem){ mxFree(mem);}

//	void *operator new[] (size_t s){ return _aligned_malloc(s, 16);}
//	void operator delete[] (void* mem){ _aligned_free(mem);}
};

#endif	//FAST_GAUSS_H