[Octave-bug-tracker] [bug #36964] incorrect low-rank product of sliced diagonal matrices

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?36964>

                 Summary: incorrect low-rank product of sliced diagonal
matrices
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Do 26 Jul 2012 13:51:20 UTC
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: André Gaul
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.2.4
        Operating System: GNU/Linux

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Details:

In Octave 3.2.4 the product of 2 sliced diagonal matrices yields a wrong
result:

octave:1> I=eye(2); U=I(:,1); U*U'
ans =

Diagonal Matrix

   1   0
   0   1

The result should be [1,0;0,0] and indeed it is correct if full() is applied
in the construction of I:

octave:2> I=full(eye(2)); U=I(:,1); U*U'
ans =

   1   0
   0   0





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  <http://savannah.gnu.org/bugs/?36964>

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