Cocal: /home/uryu/Cocal_svn_checkinout/Cocal/code/Subroutine/sphbess

00001 ! computes the r-derivative of spherical bessel functions 
00002 ! j_l(x), y_l(x), with y_l = n_l the spherical Neumann function 
00003 ! The routine uses the Numerical Recipes routine bessjy 
00004 ! input: x, l
00005 ! output: dxsj = j'_l(x), dxsy=y'_l(x)
00006 ! -----------------------------------------------------------
00007 subroutine sphbess_dx(x,l,dxsj,dxsy)
00008   implicit none
00009   real(8) :: x, dxsj, dxsy
00010   integer :: l
00011   real(8) :: rtpi2 = 1.253314154753822d0
00012   real(8) :: xnu, xrj, xry, xrjp, xryp
00013   real(8) :: oneover2x, rtpi2overx
00014 !
00015   xnu = dble(l) + 0.5d0
00016   call bessjy(x,xnu,xrj,xry,xrjp,xryp)
00017   oneover2x = 0.5d0/x
00018   rtpi2overx = rtpi2/sqrt(x)
00019   dxsj = rtpi2overx*(xrjp - oneover2x*xrj)
00020   dxsy = rtpi2overx*(xryp - oneover2x*xry)
00021 end subroutine sphbess_dx

/home/uryu/Cocal_svn_checkinout/Cocal/code/Subroutine/sphbess_dx.f90