Cocal: /home/uryu/Cocal_svn_checkinout/Cocal/code/Subroutine/sphbess.f90 Source File

00001 ! computes the spherical bessel functions j_l(x), y_l(x),
00002 ! with y_l = n_l the spherical Neumann function 
00003 ! The routine uses the Numerical Recipes routine bessjy 
00004 ! input: x, l
00005 ! output: sj = j_l(x), sy=y_l(x)
00006 ! -----------------------------------------------------------
00007 subroutine sphbess(x,l,sj,sy)
00008   implicit none
00009   real(8) :: x, sj, sy
00010   integer :: l
00011   real(8) :: rtpi2 = 1.253314154753822d0
00012   real(8) :: xnu, xrj, xry, xrjp, xryp
00013 !
00014   xnu = dble(l) + 0.5d0
00015   call bessjy(x,xnu,xrj,xry,xrjp,xryp)
00016   sj = xrj*rtpi2/sqrt(x)
00017   sy = xry*rtpi2/sqrt(x)
00018 end subroutine sphbess