[SciPy-dev] Optimization

Nils Wagner nwagner at mecha.uni-stuttgart.de
Tue Nov 29 02:53:10 CST 2005

Hi all,

How can I find the minimizer of

trace[(Y^T A Y) (Y^T Y)^{-1}],

where Y is full-rank n \times p and A is a given symmetric n \times n

p > 1 yields

  File "/usr/lib/python2.4/site-packages/scipy/optimize/optimize.py",
line 179, in fmin
    raise ValueError, "Initial guess must be a scalar or rank-1 sequence."
ValueError: Initial guess must be a scalar or rank-1 sequence.

Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/python2.4/site-packages/scipy/linalg/basic.py", line
183, in inv
    raise ValueError, 'expected square matrix'
ValueError: expected square matrix

linalg.inv(mat(2)) gives array([[ 0.5]])

linalg.inv(2) should also return 0.5




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