🚀 go-pugleaf

Pete Warren wrote:
> 
> Greetings all,
> 
> I am trying to perform large scale FFT's on complex data in a column (or
> row) wise formats.  Does anyone know of a good, proven routine for either
> Fortran (preferred) or C ?  There are routines for complex 1-D data and
> for real column wise data but not for both.
> 
> What I'm actually trying to do is build a code interface node for Labview
> that performs this function efficiently.
> 
> I would appreciate any help or pointers.
> 
> Thank you,
> 
> - Pete Warren
> warrenp@colorado.edu
The following fft subroutine is from web resourse( I am not sure where)
, maybe it helps.
      SUBROUTINE FOUREA( N, ISI)
C
C THE COOLEY-TUKEY FAST FOURIER TRANSFORM IN ANSI FORTRAN
C
C DATA IS A ONE-DIMENSIONAL COMPLEX ARRAY WHOSE LENGTH, N, IS A
C POWER OF TWO.  ISI IS +1 FOR AN INVERSE TRANSFORM AND -1 FOR A
C FORWARD TRANSFORM.  TRANSFORM VALUES ARE RETURNED IN THE INPUT
C ARRAY, REPLACING THE INPUT.
C TRANSFORM(J)=SUM(DATA(I)*W**((I-1)*(J-1))), WHERE I AND J RUN
C FROM 1 TO N AND W = EXP (ISI*2*PI*SQRT(-1)/N).  PROGRAM ALSO
C COMPUTES INVERSE TRANSFORM, FOR WHICH THE DEFINING EXPRESSION
C IS INVTR(J)=(1/N)*SUM(DATA(I)*W**((I-1)*(J-1))).
C RUNNING TIME IS PROPORTIONAL TO N*LOG2(N), RATHER THAN TO THE
C CLASSICAL N**2.
C AFTER PROGRAM BY BRENNER, JUNE 1967. THIS IS A VERY SHORT VERSION
C OF THE FFT AND IS INTENDED MAINLY FOR DEMONSTRATION. PROGRAMS
C ARE AVAILABLE IN THIS COLLECTION WHICH RUN FASTER AND ARE NOT
C RESTRICTED TO POWERS OF 2 OR TO ONE-DIMENSIONAL ARRAYS.
C SEE -- IEEE TRANS AUDIO (JUNE 1967), SPECIAL ISSUE ON FFT.
C
-Xiangyang
.