[Octave-bug-tracker] [bug #51783] [octave forge] (interval) incorrect decoration for factorial

[Joel Dahne]

URL:
  <http://savannah.gnu.org/bugs/?51783>

                 Summary: [octave forge] (interval) incorrect decoration for
factorial
                 Project: GNU Octave
            Submitted by: urathai
            Submitted on: Fri 18 Aug 2017 07:36:18 AM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: other
        Operating System: Any

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Details:

The factorial function at best gives the decoration "dac", a comment in the
code says that this is because it is not continuous.

First of all, if we say that the factorial is not continuous it should at best
have the decoration "def". The difference between "com" and "dac" is that
"dac" can be unbounded, this is clearly not the problem for the factorial in
general.

Secondly I would argue that the factorial is in fact continuous. The
requirements for "dac" is from the documentation

x is a nonempty subset of Dom(f); and the restriction of f to x is continuous

Since the domain of the factorial is exactly the natural numbers it is
continuous (the natural numbers have the discrete topology so every function
is continuous). So the decoration should be "com" in general.




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