I'm trying to do a simple 2nd degree polynomial fit to two arrays of 5 entries. I get a runtime error: RuntimeError: more argument specifiers than keyword list entries (remaining format:'|:calc_lwork.gelss') in the lstsq module inside numpy.polyfit. Here's the code snippet: def findPeak(self, ydex, xdex): # take a vertical slice vslice = [] for i in range(-1,10,1) : vslice.append(arcImage[ydex+i][xdex]) vdex = n.where(vslice == max(vslice)) ymax = ydex -1 + vdex[0][0] # approximate gaussian fit by parabolic fit to logs yvalues = n.array([ymax-2, ymax-1, ymax, ymax+1, ymax+2]) svalues=n.array([arcImage[ymax-2][xdex],arcImage[ymax-1][xdex],arcImage[ymax ][xdex],arcImage[ymax+1][xdex], arcImage[ymax+2][xdex]]) avalues = n.log(svalues) ypoly = n.polyfit(yvalues, avalues, 2) And the traceback: File "/Users/williamcarithers/BOSS/src/calibrationModel.py", line 345, in findPeak ypoly = n.polyfit(yvalues, avalues, 2) File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/ numpy/lib/polynomial.py", line 503, in polyfit c, resids, rank, s = _lstsq(v, y, rcond) File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/ numpy/lib/polynomial.py", line 46, in _lstsq return lstsq(X, y, rcond) File "/Library/Python/2.6/site-packages/scipy-0.7.1-py2.6-macosx-10.6-universal.e gg/scipy/linalg/basic.py", line 545, in lstsq lwork = calc_lwork.gelss(gelss.prefix,m,n,nrhs)[1] RuntimeError: more argument specifiers than keyword list entries (remaining format:'|:calc_lwork.gelss') This is such a simple application of polyfit and the error occurs in the guts of lstsq, so I'm completely stumped. Any help would be greatly appreciated. Thanks, Bill Carithers