[Octave-bug-tracker] [bug #55968] Incorrect simplify to sinc function

[Z. M.]

URL:
  <https://savannah.gnu.org/bugs/?55968>

                 Summary: Incorrect simplify to sinc function
                 Project: GNU Octave
            Submitted by: zmarantz
            Submitted on: Wed 20 Mar 2019 08:59:00 PM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Z.M.
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.4.0
        Operating System: Mac OS

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Details:

Hi Maintainer,

I am running Octave 4.4.0 on MAC OSX. 

I ran the following code: 

tau=0.2; A = 1.5;
syms t x(t) omega
x(t) = A*(heaviside(t+tau/2) - heaviside(t-tau/2));
X = fourier(x(t),t,omega)
X = simplify(X)
X = rewrite(X,'sinc')

The result is shown in the attached file. 

As you can see, I get sinc(w / 10).

Unfortunately, the correct answer in terms of sinc should be: sinc(w/(10pi))
especially if sinc is defined as: sinc(x) = sin(pi*x)/(pi*x).

Any assistance that you could provide would be greatly appreciated. 

Thank you,
Z.M.



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File Attachments:


-------------------------------------------------------
Date: Wed 20 Mar 2019 08:59:00 PM UTC  Name: Screen Shot 2019-03-20 at 4.55.38
PM.png  Size: 134KiB   By: zmarantz

<http://savannah.gnu.org/bugs/download.php?file_id=46595>

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