jN, jNf, yN, yNf—Bessel functions #include <math.h>
double j0(double x);
float j0f(float x);
double j1(double x);
float j1f(float x);
double jn(int n, double x);
float jnf(int n, float x);
double y0(double x);
float y0f(float x);
double y1(double x);
float y1f(float x);
double yn(int n, double x);
float ynf(int n, float x);
Description
The Bessel functions are a family of functions that solve the
differential equation
2 2 2
x y'' + xy' + (x - p )y = 0
These functions have many applications in engineering and physics.
jn calculates the Bessel function of the first kind of order
n. j0 and j1 are special cases for order 0 and order
1 respectively.
Similarly, yn calculates the Bessel function of the second kind of
order n, and y0 and y1 are special cases for order 0 and
1.
jnf, j0f, j1f, ynf, y0f, and y1f perform the
same calculations, but on float rather than double values.
Returns
The value of each Bessel function at x is returned.
Portability
None of the Bessel functions are in ANSI C.