[SciPy-dev] patch for minpack.py Newton

Ryan Krauss ryanlists at gmail.com
Fri Oct 28 13:49:42 CDT 2005


I am using the Newton algorithm in minpack.py to find the roots of a
complex expression.  This seems to work correctly, but the error
raised if it doesn't convert wasn't written with the possiblity of
complex expressions in mind.  I have changed the ending of the newton
function (line 330) from

raise RuntimeError, "Failed to converge after %d iterations, value is
%f" % (maxiter,p)

to

if type(p) is complex:
        raise RuntimeError, "Failed to converge after %d iterations,
value is %f%+fj" % (maxiter,real(p),imag(p))
    else:
        raise RuntimeError, "Failed to converge after %d iterations,
value is %f" % (maxiter,p)

This just makes the function raise a more helpful error message. 
Otherwise it reads, error float is required.

I made this change on my machine.  Is it valuable and what is the
procedure to make it part of scipy?  And is it worth doing if I am not
in the newscipy yet?

Thanks,

Ryan




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