[Numpy-discussion] Problems with linalg.cholesky?

Andrew Jaffe a.h.jaffe at gmail.com
Mon Nov 21 09:19:07 CST 2005


[Originally posted to g.c.p.user...]

Hi all,

In the newest incarnation of scipy_core, I am having trouble with the
cholesky(a) routine:

/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/scipy/linalg/basic_lite.py 

in cholesky_decomposition(a)
      115     else:
      116         lapack_routine = lapack_lite.dpotrf
--> 117     results = lapack_routine('L', n, a, m, 0)
      118     if results['info'] > 0:
      119         raise LinAlgError, 'Matrix is not positive definite -
Cholesky decomposition cannot be computed'

LapackError: Parameter a is not contiguous in lapack_lite.dpotrf

But this isn't true; I get this error even when I pass trivial and
contiguous matrices such as the output of identity(). Other linalg
routines (included complicated ones like singular_value_decomp) seem to
work fine.

Any ideas?

Andrew





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