hankel 函数源程序（F90）

xj2070 · 发表于 2005-12-2 17:23

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由于IMSL只给出了belssel的一，二类函数，但对于三四类的hankel函数晤给出，以下给出hankel程序给大家共享，并不复杂 subroutine hankel(order,class,x,res) use imsl ! This is a very useful subroutine,for that in IMSL ! the hankel function is not supported direct ! the bessel function in IMsl LIBARY is not very good ! WHEN CLASS=3 WHICH REPRENTS THE FIRST KIND BESSEL FUNCTION ! when class=4 WHICH REPRENTS THE second KIND BESSEL FUNCTION implicit None Integer order,N !the order number requried for computation Integer class !the kind number Real x,CBS1(order+1),CBS2(order+1) !argument x complex res,i 
!--------------------------------------------------------------------
 i=(0,1) ! the false root N=order+1 ! in order compute the orderth result
 Call BSJNS(x,N,CBS1) Call BSYS(0.0,x,N,CBS2) 
!--------------------------------------------------------------------
 If(class==1)Then
 res=CBS1(N)+i*(CBS2(N)) !the first kind hankel function Else if(class==2) then res=CBS1(N)-i*(CBS2(N)) !the second kind hankel function Else if(class==3) then !the REPRENTS THE FIRST KIND BESSEL FUNCTION res=CBS1(N)+i*0.0
 Else if(class==4) then ! the REPRENTS THE Second KIND BESSEL FUNCTION res=CBS2(N)+i*0.0 Else write(*,*) 'the order num is illegal' stop End if End subroutine

johhan · 发表于 2006-4-12 09:46

<DIV class=quote>以下是引用xj2070在2005-12-2 17:23:15的发言： 
由于IMSL只给出了belssel的一，二类函数，但对于三四类的hankel函数晤给出，以下给出hankel程序给大家共享，并不复杂 subroutine hankel(order,class,x,res) use imsl ! This is a very useful subroutine,for that in IMSL ! the hankel function is not supported direct ! the bessel function in IMsl LIBARY is not very good ! WHEN CLASS=3 WHICH REPRENTS THE FIRST KIND BESSEL FUNCTION ! when class=4 WHICH REPRENTS THE second KIND BESSEL FUNCTION implicit None Integer order,N !the order number requried for computation Integer class !the kind number Real x,CBS1(order+1),CBS2(order+1) !argument x complex res,i 
!--------------------------------------------------------------------
 i=(0,1) ! the false root N=order+1 ! in order compute the orderth result
 Call BSJNS(x,N,CBS1) Call BSYS(0.0,x,N,CBS2) 
!--------------------------------------------------------------------
 If(class==1)Then
 res=CBS1(N)+i*(CBS2(N)) !the first kind hankel function Else if(class==2) then res=CBS1(N)-i*(CBS2(N)) !the second kind hankel function Else if(class==3) then !the REPRENTS THE FIRST KIND BESSEL FUNCTION res=CBS1(N)+i*0.0
 Else if(class==4) then ! the REPRENTS THE Second KIND BESSEL FUNCTION res=CBS2(N)+i*0.0 Else write(*,*) 'the order num is illegal' stop End if End subroutine</DIV>
请教楼主,IMSL其中的函数如何调用呢? 比如讲FFT,谢谢!!!

xj2070 · 发表于 2006-4-12 12:18

use IMSL ... FFTRF/DFFTRF (Single/Double precision) Compute the Fourier coefficients of a real periodic sequence. Usage CALL FFTRF (N, SEQ, COEF) Arguments N — Length of the sequence to be transformed. (Input) SEQ — Array of length N containing the periodic sequence. (Input) COEF — Array of length N containing the Fourier coefficients. (Output) Comments 1. Automatic workspace usage is FFTRF 2N + 15 units, or DFFTRF 4N + 30 units. Workspace may be explicitly provided, if desired, by use of F2TRF/DF2TRF. The reference is CALL F2TRF (N, SEQ, COEF, WFFTR) The additional argument is WFFTR — Array of length 2N + 15 initialized by FFTRI (page 770). (Input) The initialization depends on N. 2. The routine FFTRF is most efficient when N is the product of small primes. 3. The arrays COEF and SEQ may be the same. 4. If FFTRF/FFTRB is used repeatedly with the same value of N, then call FFTRI followed by repeated calls to F2TRF/F2TRB. This is more efficient than repeated calls to FFTRF/FFTRB.

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[数学理论] hankel 函数源程序（F90）

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