[SciPy-User] weird TypeError: only length-1 arrays can be converted to Python scalars

[Wolfgang Kerzendorf]

Dear all,

I have come across a weird error, in which the traceback doesn't really 
reflect the problem (ah osx 10.6.7, python2.6, np 1.6, sp 0.9, ipython 
0.10.1, mpl 1.0.1):

----
   File "weird_error.py", line 8, in <module>
     fmin.simplex()
   File "/Users/wkerzend/scripts/python/pyspecgrid/specgrid.py", line 
134, in __call__
     gridSpec = self.specGrid.getSpec(*args)
   File "/Users/wkerzend/scripts/python/pyspecgrid/specgrid.py", line 
235, in getSpec
     return oned.onedspec(self.wave, self.interpGrid(args), mode='waveflux')
   File "interpnd.pyx", line 120, in 
interpnd.NDInterpolatorBase.__call__ (scipy/interpolate/interpnd.c:1896)
   File "interpnd.pyx", line 142, in interpnd._ndim_coords_from_arrays 
(scipy/interpolate/interpnd.c:2145)
   File "/Library/Python/2.6/site-packages/numpy/lib/stride_tricks.py", 
line 69, in broadcast_arrays
     args = map(np.asarray, args)
   File "/Library/Python/2.6/site-packages/numpy/core/numeric.py", line 
235, in asarray
     return array(a, dtype, copy=False, order=order)
TypeError: only length-1 arrays can be converted to Python scalars
------

I have debugged it here:
--> 235     return array(a, dtype, copy=False, order=order)
     236

ipdb> a
a = 0.1
dtype = None
order = None
ipdb> type(a)
<type 'float'>

----------------

It just doesn't make sense to me, please help,
     Wolfgang