[seqfan] Re: Maple strongly discouraged

[Charles Greathouse]

Actually that should be

# Warning: The RETURN function may produce incorrect answers in Maple 17+.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University


On Sun, Jan 12, 2014 at 1:17 PM, Charles Greathouse <
charles.greathouse at case.edu> wrote:

> If we're going to make a warning, let's use
>
> # Warning: The RETURN command may produce incorrect answers in Maple 17+.
>
> This avoids putting us in the position of encouraging any particular
> language, and gives an implicit solution: use version 16 or earlier.
>
> Charles Greathouse
> Analyst/Programmer
> Case Western Reserve University
>
>
> On Sun, Jan 12, 2014 at 1:07 PM, Neil Sloane <njasloane at gmail.com> wrote:
>
>> Dear Seq Fans, Maximilian Hasler has pointed out that
>> my Maple program in A109671 (which worked correctly in Maple 16)  no
>> longer gives correct results in Maple 17 because it used the RETURN()
>> command.
>>
>> The Maple web site says
>>
>> "use of the RETURN procedure is strongly discouraged"
>>
>> and I can see why - it produces incorrect answers (without any warning).
>> Of
>> course I don't see WHY they did this.
>>
>> Now there over 1900 Maple lines in the OEIS that use the RETURN statement.
>>  Maybe these lines need a comment saying:
>>
>> # Warning: May give incorrect answers because Maple has changed the
>> meaning
>> of RETURN. Suggest switching to Mathematica instead.
>>
>> (Not sure about the second part)
>>
>> I could (and probably will have to) do this with a global edit.
>> Is there any other solution?  It is unethical for us to include programs
>> that give wrong answers.
>>
>> Here's the Maple program that works correctly in Maple 16 but gives wrong
>> answers  in Maple 17:
>>
>> > f:=proc(n) option remember; local t1;
>>
>> > if n = 1 then RETURN(1);
>>
>> > elif n mod 2 = 0 then RETURN(f(n/2));
>>
>> > else t1:= f(n-2)-f((n-1)/2);
>>
>> > if t1 > 0 then RETURN(t1) else RETURN(f(n-2)+f((n-1)/2)); fi; fi; end;
>>
>> Neil
>> --
>> Dear Friends, I have now retired from AT&T. New coordinates:
>>
>> Neil J. A. Sloane, President, OEIS Foundation
>> 11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
>> Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
>> Phone: 732 828 6098; home page: http://NeilSloane.com
>> Email: njasloane at gmail.com
>>
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>>
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>
>