[Octave-bug-tracker] [bug #46912] qr not working as described

[Marco Caliari]

Follow-up Comment #4, bug #46912 (project octave):

Thanks,

I did not try, but from your patch it seems to me:

1) qr(A,'matrix'), A full, throws an error. This is not compatible with
Matlab. In fact, [Q,R]=qr(A,'matrix') just works in Matlab and
[Q,R,P]=qr(A,'matrix') returns P as a permutation matrix (default behavior).
UPDATE: this is true for ML2014b, but it seems that ML2015b changed a little
bit

http://it.mathworks.com/help/symbolic/qr.html

Can anyone test [Q,R]=qr(rand(4),'matrix') and [Q,R,P]=qr(rand(4),'matrix')
with ML2015b?

2) ML2015b changed other things: the option '0' seems to be not supported
anymore and replaced with 'econ'. Can anyone test [Q,R]=qr(rand(4),0) with
ML2015b?

3) the option 'vector' is not supported in Octave. It is similar to '0', but
zero rows of R are not omitted. For instance


A=reshape(1:6,3,2)
[Q,R,P]=qr(A,'vector')
Q =

   -0.4558    0.7909    0.4082
   -0.5698    0.0930   -0.8165
   -0.6838   -0.6048    0.4082


R =

   -8.7750   -3.6467
         0   -0.8374
         0         0


P =

     2     1


4) In the description of [Q,R,P]=qr(A) I would add that Q*R=A*P

5) The new option 'real' in ML2015b is not supported.

Sorry that I did not report all the issues in the original submission.


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