Re: Easy project for GSoC students

[Juan Pablo Carbajal]

On Sat, Mar 8, 2014 at 1:42 PM, Eduardo <address@hidden> wrote:
>
> Hi Pablo,
>
> Should the the parameters be checked to be as they are in the m-file inside
> the mechanics module? I mean, N should be a scalar, and r and c may be
> vectors of the same size containing scalars or just scalars. Is that
> correct?
>
> Edu
>
>
>
> 2014-03-06 23:57 GMT+01:00 Juan Pablo Carbajal <address@hidden>:
>
>> Dear GSoC applicants,
>>
>> Please use the mailing list to ask questions, you gain nothing by
>> writing a particular person. Indeed you loose the chance to get other
>> developers to answer your questions.
>>
>> Many of you have asked for easy projects. The bug tracker is a source
>> of  possible projects. Here there is another one (I added it to the
>> tracker)
>>
>>
>> === extend sub2ind and ind2sub ===
>> We are extending sub2ind and ind2sub to work with triangular matrices.
>> Currently private functions of the mechanics package.
>> A string argument triggers the behavior. The string argument can be
>> "triu" or "tril". After this str argument we accept an extra scalar
>> value indicating that the triangular matrix is off diagonal (as in
>> tril and triu).
>> So, the first modification to the C++ code will be
>> # Check if any of the argument is a str.
>> # Check what kind of triangular matrix (up or low).
>> # If the argument after the str argument is a scalar, it indicates off
>> diagonal triangular matrix (we do not have algo for that yet, though).
>
>
Hi Edu,

That's correct.
Notice that the best approch would be to go for a separate ind2sub_tri
that accepts "up" and "low" as options and then add the callback to
the standard ind2sub (assuming jwe doesn't complain too much, but
since is easy to remove the functionality if mathworks ever decides to
implement it, I do not think that is the case) then yes, you have to
perform those checks. The algorithm implemented on the mechanical
package functions works for square triangular matrices and it doesn't
work with an offset.