[Numpy-discussion] NumPy/SciPy LAPACK version

Kevin Jacobs <jacobs@bioinformed.com> bioinformed@gmail....
Mon Jul 16 08:52:25 CDT 2007


Hi all,

This is a bit of a SciPy question, but I thought I'd ask here since I'm
already subscribed.  I'd like to add some new LAPACK bindings to SciPy and
was wondering if there was a minimum version requirement for LAPACK, since
it would be ideal if I could use some of the newer 3.0 features.  In
addition to using some block methods only added in 3.0, it is very
convenient to use the WORK=-1 for space queries instead of reimplementing
the underlying logic in the calc_work module.

The routines of most interest to me are:
DGELSD
DGGGLM
DGGLSE

I've also found that SciPy's sqrtm is broken:

>>> a=matrix([[59, 64, 69],
        [64, 72, 80],
        [69, 80, 91]])
>>> sqrtm(a)
array([[ 5.0084801  +1.03420519e-08j,  4.40747825 -2.06841037e-08j,
         3.8064764  +1.03420519e-08j],
       [ 4.40747825 -2.06841037e-08j,  4.88353492 +4.13682075e-08j,
         5.3595916  -2.06841037e-08j],
       [ 3.8064764  +1.03420519e-08j,  5.3595916  -2.06841037e-08j,
         6.9127068  +1.03420519e-08j]])
>>> sqrtm(a)*sqrtm(a)
array([[ 25.08487289 +1.03595922e-07j,  19.42586452 -1.82329475e-07j,
         14.48926259 +7.87335527e-08j],
       [ 19.42586452 -1.82329475e-07j,  23.84891336 +4.04046172e-07j,
         28.72522212 -2.21716697e-07j],
       [ 14.48926259 +7.87335527e-08j,  28.72522212 -2.21716697e-07j,
         47.78551529 +1.42983144e-07j]])

So not even close...  (and yes, it does deserve a bug report if one doesn't
already exist)

-Kevin
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