[LON-CAPA-users] submission masaging
Peter Riegler
lon-capa-users@mail.lon-capa.org
Thu, 17 Jul 2008 21:40:04 +0200
Hi Bob,
below is a guess what is going on. To give a more reliable answer I
would need to see the source code of the problem.
Bob Gonzales wrote:
> What kind of massaging does LONCAPA do
> to the string of text that is entered
> for an answer?
>
> I ran into a situation where a student entered
> the number 1.1e-7 as 1.1 e-7. LONCAPA took out
> the spaces before it checked the answer and then
> marked the problem correct.
Presumably, you are using formularesponse or mathresponse. There, prior
to grading the submission is passed through a function named
&implicit_multiplication. Among other things it interprets suitable
spaces as multiplication operators (which is perfectly fine for
1.1<space>e-7).
> I then grabbed the
> submission (via &EXT) and assigned it to a variable
> and then used the variable in a calculation, without
> removing spaces (who would have thought...) and got
> an answer I didn't expect. Interestingly, LONCAPA
> used the mantissa (the 1.1 part) in the calculation and
> ignored the rest of the submission.
Well, this was Perl. Your 1.1 e-7 entered as a string in your
calculation, but within the context of a calculation was converted into
a number.
>
> So, I guess I need to massage the submission
> the same way LONCAPA does in order to avoid
> this situation in the future.
Me too. Wrapping an &implicit_multiplication() around the submission
should do it.
Hope this will help
Peter
>
> Thanks,
> Bob Gonzales
> Chemistry Dept
> Binghamton University
>
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--
Peter Riegler
Fachhochschule Braunschweig/Wolfenbüttel
Salzdahlumer Str. 46/48, 38302 Wolfenbüttel
Tel. +49 5331 939 6314, Fax. +49 5331 939 6002
email: p.riegler@fh-wolfenbuettel.de
http://public.rz.fh-wolfenbuettel.de/~riegler