[SciPy-User] How to print the jacobian in the output of leastsq function

Charles R Harris charlesr.harris@gmail....
Wed Aug 24 23:11:17 CDT 2011


On Tue, Aug 23, 2011 at 9:57 AM, Abraham Zamudio
<abraham.zamudio@gmail.com>wrote:

> Hi All,
>
> i use  the leastsq function from module scipy ... but what I want now
> is the jacobian matrix of the algorithm ... How should I use this
> function to print the Jacobian ??? .
>
>
That's tricky, as what is returned is the qr factorization of the Jacobian
stored in condensed form containing the r part and what I think are the
vectors of the Householder reflections that can be used to generate q. In
addition, the columns are pivoted. So I think it would take a bit of
research and work to recover the Jacobian. Perhaps someone here knows a bit
more about the specific function used in this function. If you just want the
covariance of the coefficients, that is easier to get, but note the
documentation is incorrect, you need to multiply by the variance, not the
standard deviation.

Chuck
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