HP C/iX Library Reference Manual (30026-90004)
Chapter 5 115
HP C/iX Library Function Descriptions
Bessel Functions
Bessel Functions
The Bessel functions are j0, j1, jn, y0, y1, and yn.
Syntax
#include <math.h>
double j0 (double
x
);
double j1 (double
x
);
double jn (int
i
, double
x
);
double y0 (double
x
);
double y1 (double
x
);
double yn (int
i
, double
x
);
Parameters
x
A real number input to the Bessel functions.
i
An integer value indicating the order to use when calculating the Bessel
functions.
Return Values
n The result of the Bessel function.
-HUGE The input arguments are non-positive.
0 The input argument is too large in magnitude. In addtion, errno is set to
ERANGE.
Description
The j0 and j1 functions return Bessel functions of
x
of the first kind of orders zero and 1,
respectively. The jn function returns the Bessel function of
x
of the first kind of order
i
.
The y0 and y1 functions return the Bessel functions of
x
of the second kind of orders zero
and 1, respectively. The yn function returns the Bessel function of
x
of the second kind of
order
i
. The value of
x
must be positive.
Non-positive arguments cause y0, y1, and yn to return the value -HUGE and sets errno to
EDOM. They also cause a message indicating a DOMAIN error to be printed on the standard
error output, but the process continues.
Arguments too large in magnitude cause j0, j1, jn, y0, y1 and yn to return zero and to set
errno to ERANGE. In addition, a message indicating TLOSS error is printed on the standard
error output.