[SciPy-user] Error message I don't understand
rkern at ucsd.edu
Thu Jul 28 14:26:10 CDT 2005
Christian Meesters wrote:
> I get this weird Traceback from my script:
> Traceback (most recent call last):
> File "FP.py", line 111, in ?
> File "FP.py", line 67, in main
> File "FP.py", line 98, in fitter
> tck = interpolate.splrep(ml,OD)
> File "/platlib/scipy/interpolate/fitpack.py", line 339, in splrep
> SystemError: error return without exception set
> The "fitter"-function so far contains only this line which causes the
> error. 'OD' and 'ml' are array objects. Running the example code from
> the tutorial does not result in any error. (And looking into fitpack.py
> didn't help.)
> Has anybody seen this error before and knows how to solve the problem?
> It's probably something really stupid, but I failed finding the solution.
It's an obscure error stating that somewhere inside the extension
module, a function returned NULL instead of a real pointer to a
PyObject. That's the signal for raising an error in extension functions.
However, there is a bug somewhere, and the actual exception has not been
Looking at the source, I believe that the bug is on line 367 of
Lib/interpolate/__fitpack.h in fitpack_curfit(). It's just after the
call to the computation routine:
if (ier==10) goto fail;
An appropriate exception needs to be set here.
In the meantime, here is the FITPACK documentation about this error code:
c ier=10 : error. on entry, the input data are controlled on validity
c the following restrictions must be satisfied.
c -1<=iopt<=1, 1<=k<=5, m>k, nest>2*k+2, w(i)>0,i=1,2,...,m
c xb<=x(1)<x(2)<...<x(m)<=xe, lwrk>=(k+1)*m+nest*(7+3*k)
c if iopt=-1: 2*k+2<=n<=min(nest,m+k+1)
c the schoenberg-whitney conditions, i.e. there
c must be a subset of data points xx(j) such that
c t(j) < xx(j) < t(j+k+1), j=1,2,...,n-k-1
c if iopt>=0: s>=0
c if s=0 : nest >= m+k+1
c if one of these conditions is found to be violated,control
c is immediately repassed to the calling program. in that
c case there is no approximation returned.
rkern at ucsd.edu
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter
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