leastSquaresFit

[Alex Tournier]

Here's a question/problem with the leastSquaresFit function which is
part of Numeric module.Hope you can help,

I try the example given in the documentation and here is what i get:

>>> from Scientific.Functions.LeastSquares import leastSquaresFit
>>> import Numeric
>>>
>>> # The mathematical model.
... def exponential(parameters, x):
...     a = parameters[0]
...     b = parameters[1]
...     return a*Numeric.exp(-b/x)
...
>>> # The data to be fitted to.
... data = [(100, 4.999e-8),
...     (200, 5.307e+2),
...     (300, 1.289e+6),
...     (400, 6.559e+7)]
>>>
>>> fit = leastSquaresFit(exponential, (1e13, 4700), data)
Traceback (innermost last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/python1.5/site-packages/Scientific/Functions/LeastSquares.py",
line 66, in leastSquaresFit
    -0.5*Numeric.array(chi_sq[1]))
  File "/usr/lib/python1.5/site-packages/Numeric/LinearAlgebra.py",
line 61, in solve_linear_equations
    _assertRank2(a, b)
  File "/usr/lib/python1.5/site-packages/Numeric/LinearAlgebra.py",
line 47, in _assertRank2
    raise LinAlgError, 'Array must be two-dimensional'
LinearAlgebraError: Array must be two-dimensional


Anybody have an idea were this might come from, I use the Numeric
module all the time without any prob, but I can't get this
leastSquaresFit function to work!!

Cheers,

Alex