/*
   pa.h

   Header file for definitions of functions used in the computation of
   piece-wise analytic fits based on sample data.

   Ramses van Zon, December 5, 2009

   Reference:
   [] Ramses van Zon and Jeremy Schofield, "Constructing smooth
      potentials of mean force, radial distribution functions and
      probability densities from sampled data", 
      arxiv.0912.0465 [cond-mat.stat-mech].
*/

#ifndef _PAH_
#define _PAH_

#include <stdio.h>

/* structure to hold the information on a piece-wise analytic fit. */
struct Pafit {
  int k;
  double *a;
  double *b;
  double *c;
  double **d;
  double *f;
  double *g;
};

/* perform a weighted resampling of data. */
double pabias( int n, const double *r, double (*w)(double), void *s, 
               double *x );

/* perform a weighted resampling of data for use with a jackknife. */
double pajbias( int j, int m, int n, const double *r,
                double (*w)(double), void *s,
                double*x );

/* perform a resampling of data for use with a bootstrap estimator. */ 
void paboot( int n, const double *r, void *s, double *x );

/* perform a simple block-jackknife. */
void pajack( int j, int m, int n, const double *r, double *x );

/* perform a resampling of data for use with a block-jackknife. */
void pajackboot( int j, int m, int n, const double *r, void *s,
                 double *x );

/* allocate memory for the arrays used by pafit. */ 
struct Pafit* paalloc( int km, int mm );

/* release the memory allocated by paalloc. */
void pafree( struct Pafit *pa );

/* computes the parameters of the piecewise analytic fit to a
   probability distribution from data. */
double pafit( int n, const double *r, double qm,
              int km, int mm, int nodiscont, 
              struct Pafit *pa );

/* evaluate the piecewise analytic probability distribution at a */
double papd( double r, struct Pafit *pa );

/* evaluate the piecewise analytic cumulative distribution. */
double pacd( double r, struct Pafit *pa );

/* write the fit parameters found by pafit to a file. */
void pawrite( FILE *file, struct Pafit *pa );

/* sorting routine for an array of doubles */
void pasort( int n, double *x );

/* read a binary data file of a specific format into an array. */
double* readbinfile( const char *s, double *y1, double *y2, int *m, int *n );

#endif