pi_funcs.c File Reference

#include <math.h>

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Macros
#define	PI   3.14159265359

Functions
double	f_allometric (double x, double A[])
double	f_arctangent (double x, double A[])
double	f_exponential (double x, double A[])
double	f_gen_gompertz (double x, double A[])
double	f_logistic (double x, double A[])
double	f_gen_poisson_density (double x, double A[])

Macro Definition Documentation

#define PI   3.14159265359

Function Documentation

double f_allometric	(	double	x,
		double	A[]
	)

    {
      return x <= 0.0 ? 0.0 : A[0] * pow(x, A[1]);
    }

double f_arctangent	(	double	x,
		double	A[]
	)

    {
      return(A[1] + (A[2] / PI) *
             atan(PI * A[3] * (x - A[0])));
    }

double f_exponential	(	double	x,
		double	A[]
	)

    {
      return(A[0] * exp((A[1] * x)));
    }

double f_gen_gompertz	(	double	x,
		double	A[]
	)

    {
      double tmp1, tmp2;      /* temp values */

      if (A[1] <= 0.0) {
        return 0.0;
      }

      tmp1 = pow(A[1], (A[3] * x));
      tmp2 = pow(A[1], A[2] / tmp1);

      return(A[0] / tmp2);
    }

double f_gen_poisson_density	(	double	x,
		double	A[]
	)

    {
      double tmp1, tmp2, tmp3;

      if (A[1] == A[0]) {
        return(0.0);
      }

      tmp1 = ((A[1] - x) / (A[1] - A[0]));
      if (tmp1 <= 0.0) {
        return 0.0;
      }

      tmp2 = 1.0 - pow(tmp1, A[3]);
      tmp3 = pow(tmp1, A[2]);
      return (exp(A[2] * tmp2 / A[3]) * tmp3);
    }

double f_logistic	(	double	x,
		double	A[]
	)

    {
      return(A[0] / (1.0 + A[1] / exp((A[2] * x))));
    }