Fortran 2008 (PR 33197) supports the BESSEL_* functions. However, for BESSEL_*N there are two versions:
A) An elemental function BESSEL_YN(N, X) and BESSEL_JN(N,X) B) An transformational function BESSEL_YN(N1,N2,X) and BESSEL_JN(N1,N2,Y) (B) Is currently not supported: The result of BESSEL_JN (N1, N2, X) is a rank-one array with extent MAX(N2−N1+1,0). Element i of the result value of BESSEL_JN (N1, N2, X) is a processor-dependent approximation to the Bessel function of the first kind and order N1+i − 1 of X. Note that one needs to simplify also the transformational version as one can also use it in initialization expressions. See also PR 36096 and 36117 and http://groups.google.com/group/comp.lang.fortran/browse_thread/thread/e9add97708681397 -- Summary: Transformational function BESSEL_YN(n1,n2,x) and BESSEL_JN missing Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: burnus at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36158