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libprob.h

#ifndef LIBPROB_H
#define LIBPROB_H

/* area under the binomial pdf, from 0 to k, of the
   binomial distribution with success probability p
   and n trials.
*/
double bdtr (int k, int n, double p);

/* area under the binomial pdf, from k+1 to n, of the
   binomial distribution with success probability p
   and n trials. 
*/
double bdtrc (int k, int n, double p);

/* success probability such that the area under the 
   binomial pdf from 0 to k with n trials equals y.
*/
double bdtri (int k, int n, double y);

/* area under the left hand tail (from 0 to x)
   of the Chi square probability density function with
   v degrees of freedom.
*/
double chdtr (double v, double x);

/* area under the right hand tail (from x to infinity)
   of the Chi square probability density function with
   v degrees of freedom.
*/
double chdtrc (double v, double x);

/*
   Finds the Chi-square argument x such that the integral
   from x to infinity of the Chi-square density is equal
   to the given cumulative probability y.
*/
double chdtri (double df, double y);

/*
   Returns the area from 0 to x under the F density
   function (also known as Snedcor's density or the
   variance ratio density).
*/
double fdtr (int ia, int ib, double x);

/*
   Returns the area from x to infinity under the F density
   function (also known as Snedcor's density or the
   variance ratio density).
*/
double fdtrc (int ia, int ib, double x);

/*
   Finds the F density argument x such that the integral
   from x to infinity of the F density is equal to the
   given probability p.
*/
double fdtri (int ia, int ib, double y);

/*
   Computes the integral from minus infinity to t of the Student
   t distribution with k > 0 degrees of freedom.
*/
double stdtr (double rk, double t);

/*
   Given probability p, finds the argument t such that stdtr(k,t)
   is equal to p.
*/
double stdtri (double rk, double p);

/*
   Returns the area under the Gaussian probability density
   function, integrated from minus infinity to x.
*/
double ndtr (double a);

/*
   Returns the argument, x, for which the area under the
   Gaussian probability density function (integrated from
   minus infinity to x) is equal to y.
*/
double ndtri (double y0);

/*
  Returns the sum of the first k terms of the Poisson
  distribution with mean and variance m.
*/
double pdtr (int k, double m);

/*
  Returns the sum of the terms k+1 to infinity of the Poisson
  distribution with mean and variance m.
*/
double pdtrc (int k, double m);

/*
  Finds the Poisson variable x such that the integral
  from 0 to x of the Poisson density is equal to the
  given probability y.  
*/
double pdtri (int k, double y);

/* Returns the integral from zero to x of the gamma pdf
   with XX.
*/
double gdtr (double a, double b, double x);

/* Returns the integral from x to infinity of the gamma
   pdf with XX.
*/
double gdtrc (double a, double b, double x);

/* 
   Returns the inverse incomplete gamma function.
*/
double igami( double a, double y0 );
/*
   Returns gamma function of the argument.  The result is
   correctly signed.
*/
double cephes_gamma (double x); /* cephes' gamma(), renamed */

/*
   Returns the base e (2.718...) logarithm of the absolute
   value of the gamma function of the argument.
   The sign (+1 or -1) of the gamma function is set in a
   global variable named cephes_sgngam.
*/
double cephes_lgamma (double x); /* alias for cephes' lgam() */

/* Returns the current value of cephes_sgngam */
int get_cephes_sgngam (void);

/* Returns the Psi (digamma) function of the argument */
double psi (double x);

/* Evaluate roots of polynomial */
int polrt (double *xcof, double *cof, int m, cmplx *root);

/* Accessor for cephes error code */
int get_cephes_errno (void);

#endif /* LIBPROB_H */

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