IFFT! Scaling Error

[email protected] Mon, 05 Apr 2004 07:45:06 -0400
Newsgroups gmane.lisp.matlisp.user
Message-ID <[email protected]>
All,

1.  I noted a 1/N scaling error in IFFT! in the CVS code.  This was
    not present in my local working copy.  I suspect I caused this
    some time back and apologize.

2.  Can someone verify this change and update CVS?  The simple test 
    I used was (m:ifft! (m:fft (m:ones 8 3))) and (m:ifft! (m:fft (m:ones 8 1)))

3.  The diff's are...

*** /home/mak/src/matlisp/src/fft.lisp	2003-02-24 17:30:21.000000000 -0500
--- /usr/local/src/matlisp/src/fft.lisp	2004-04-02 14:07:09.000000000 -0500
***************
*** 395,401 ****
      (if (row-or-col-vector-p x)
  	(progn
  	  (zfftb n (store x) wsave)
! 	  x)
  
        ;; IFFT by column
        (scal! (/ (float n 1d0))
--- 395,401 ----
      (if (row-or-col-vector-p x)
  	(progn
  	  (zfftb n (store x) wsave)
! 	  (scal! (/ (float n 1d0)) x))
  
        ;; IFFT by column
        (scal! (/ (float n 1d0))


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tnx
mike


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