diff options
Diffstat (limited to 'numpy/lib/polynomial.py')
| -rw-r--r-- | numpy/lib/polynomial.py | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/numpy/lib/polynomial.py b/numpy/lib/polynomial.py index 18250700b..fa165dda1 100644 --- a/numpy/lib/polynomial.py +++ b/numpy/lib/polynomial.py @@ -11,11 +11,14 @@ import warnings import numpy.core.numeric as NX from numpy.core import isscalar, abs +from numpy.lib.machar import MachAr from numpy.lib.twodim_base import diag, vander from numpy.lib.shape_base import hstack, atleast_1d from numpy.lib.function_base import trim_zeros, sort_complex eigvals = None lstsq = None +_single_eps = MachAr(NX.single).eps +_double_eps = MachAr(NX.double).eps def get_linalg_funcs(): "Look for linear algebra functions in numpy" @@ -170,7 +173,7 @@ def polyder(p, m=1): val = poly1d(val) return val -def polyfit(x, y, deg, rcond=-1): +def polyfit(x, y, deg, rcond=None): """ Do a best fit polynomial of degree 'deg' of 'x' to 'y'. Return value is a @@ -241,6 +244,14 @@ def polyfit(x, y, deg, rcond=-1): if x.shape[0] != y.shape[0] : raise TypeError, "expected x and y to have same length" + # set rcond + if rcond is None : + xtype = x.dtype + if xtype == NX.single or xtype == NX.csingle : + rcond = _single_eps + else : + rcond = _double_eps + # scale x to improve condition number scale = abs(x).max() if scale != 0 : @@ -253,7 +264,7 @@ def polyfit(x, y, deg, rcond=-1): # warn on rank reduction, which indicates an ill conditioned matrix if rank != order : # fixme -- want a warning here, not an exception - raise RuntimeError, "degree reduced to %d" % (rank - 1) + raise RuntimeError, "Rank deficit fit. Try degree %d." % (rank - 1) # scale returned coefficients if scale != 0 : |