[Numpy-discussion] Efficient orthogonalisation with scipy/numpy

[Anne Archibald]

2010/1/19 Gael Varoquaux <gael.varoquaux at normalesup.org>:

> For the google-completness of this thread, to get a speed gain, one needs
> to use the 'econ=True' flag to qr.

Be warned that in some installations (in particular some using ATLAS),
 supplying econ=True can cause a segfault under certain conditions (I
think only when the arrays are misaligned, e.g. coming from
unpickling, and even then only with certain data); the bugfix for this
may or may not be complete, and involves copying misaligned arrays.

Anne