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## Re: leasqr problem - covp is 'NA'!!!

**From**: |
Dmitri A. Sergatskov |

**Subject**: |
Re: leasqr problem - covp is 'NA'!!! |

**Date**: |
Mon, 18 Apr 2011 14:11:25 -0500 |

On Mon, Apr 18, 2011 at 1:22 PM, Przemek Klosowski
<address@hidden> wrote:
>* The covariance matrix results in sqrt(diag(covp))) values of 77.468751*
>* 77.468741 0.061083 90.835584. These values look strange, given the*
>* goodness of the fit; I haven't dwelved into it but the covp matrix looks*
>* strange--- approximately*
>
>* 1000 * [1 -1 0 1; -1 1 0 -1; 0 0 0 0; 1 -1 0 1]*
>
>* which doesn't make sense to me but I haven't thought about it long enough to*
>* convince myself one way or the other. Practitioners of leasqr, what do you*
>* think about the reliability of covp values?*
>
I think there are too many fit parameters.
The fit functions essentially a+b*exp(c*x).
Dmitri.
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