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[Scalapack] complex pivoted qr factorisation

Hello David,

Thank you for the report.  It looks like this is probably a bug -- we will take 
a look at this and hopefully get a fix in place sometime in the near future.

--Rodney

On Oct 18, 2011, at 9:32 PM, David Wang wrote:

Hello Scalapack,

I have been using the pivoted QR factorisation routine (pzgeqpf) from
scalapack-1.8.0.  I have found that, in some cases, the diagonal
elements of the R matrix are not arranged in order of descending
magnitude as described in the user's guide.  I have attached a test
case for you to verify.  e.g. I get something like:

R(0,0) -0.707107 + 0i
R(1,1) -0.707107 + 0i
R(2,2) 8.16273e-17 + 0i
R(3,3) -0.243173 + 0i
R(4,4) 4.82605e-17 + 0i

This behaviour can be reproduced for the single precision complex case
(although not with the supplied test matrix).  The same test case
works for the real case (pdgeqpf).  e.g.

R(0,0) -0.707107
R(1,1) -0.707107
R(2,2) 0.5
R(3,3) 3.96991e-17
R(4,4) 2.2336e-17

I have not had any problems with the equivalent lapack routines (zgeqp3),
and have not see any mention of this in the errata.

David
<pzgeqpf_test.c><pdgeqpf_test.c>_______________________________________________
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