BESSEL_JN — Bessel function of the first kind#

BESSEL_JN(N, X)#

BESSEL_JN(N, X) computes the Bessel function of the first kind of order N of X. This function is available under the name BESJN as a GNU extension. If N and X are arrays, their ranks and shapes shall conform.

Parameters:

N – Shall be a scalar or an array of type INTEGER.
N1 – Shall be a non-negative scalar of type INTEGER.
N2 – Shall be a non-negative scalar of type INTEGER.
X – Shall be a scalar or an array of type REAL ; for BESSEL_JN(N1, N2, X) it shall be scalar.

Returns:

The return value is a scalar of type REAL. It has the same kind as X.

Standard:

Fortran 2008 and later, negative N is allowed as GNU extension

Class:

Elemental function, except for the transformational function BESSEL_JN(N1, N2, X)

Syntax:

RESULT = BESSEL_JN(N, X)
RESULT = BESSEL_JN(N1, N2, X)

Note:

The transformational function uses a recurrence algorithm which might, for some values of X, lead to different results than calls to the elemental function.

Example:

program test_besjn
  real(8) :: x = 1.0_8
  x = bessel_jn(5,x)
end program test_besjn

Specific names:

Name	Argument	Return type	Standard
`DBESJN(N, X)`	`INTEGER N`	`REAL(8)`	GNU extension
	`REAL(8) X`