On 17-Feb-2010, Steven De Herdt wrote: | While working with complex matrices, I noticed strange things going on. | Some searching showed that there is definitely something wrong: | | octave3.2:2> a=orth(randn(3)); | octave3.2:3> a'*a | ans = | | 1.0000e+00 -1.0742e-16 2.2264e-16 | -1.0742e-16 1.0000e+00 -3.1537e-17 | 2.2264e-16 -3.1537e-17 1.0000e+00 | | octave3.2:4> b=orth(randn(3)+J*randn(3)); | octave3.2:5> b'*b | ans = | | 1.06482 + 0.00000i 0.10484 + 0.51574i 0.14882 + 0.71172i | 0.10484 - 0.51574i 0.90395 + 0.00000i -0.07914 + 0.08895i | 0.14882 - 0.71172i -0.07914 - 0.08895i 1.06476 + 0.00000i | | The result is Hermitian, but not quite unitary. | This also happens on octave3.0, but not on amd64 (either version). | | A look through Octave's own bug reports produces e.g. | http://old.nabble.com/wrong-output-for-complex-scalar-product-to26766409.html and | http://old.nabble.com/Wrong-results-for-svd-on-complex-numbers-to27079479.html , | so this kind of problem is not unheard of. | | Depending on one's needs, this may be an 'important' bug.
I don't see this result on my system (Debian testing, amd64). I suspect a bug in the lapack package on your system. jwe -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
