Re: root finder

Hi,

 The algorithm returns only one root, normally the first one found in the given range [a,b] in the case you are using a method not using the function derivatives (like the Brent finder). If you know another root exists, you can then re-run the algorithm on the remaining subrange [root1,b] to find the second root. Without knowing the shape of the function is difficult to build a generic algorithm to find all roots. See also http://root.cern.ch/phpBB3//viewtopic.php?f=3&t=8822

where I have attached a possible example macro, FindRoot.C

 Best Regards

 Lorenzo  

On Sep29, 2010, at 12:34 PM, Julia Campa Romero wrote:

> Hi,
>
> I want to ask if the rootfinder classes give you more that one root.
> I want to find the roots from the intersection of a Gaussian function with a straight line. I am testing the programs that are at
> http://root.cern.ch/drupal/content/root-finder-algorithms
> If I try to get more that one roots making larger the interval for example (0, 6*pi())
> it only gives me one
> how could I get more?
>
> Thanks,
>
> Julia
>
>
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Received on Wed Sep 29 2010 - 15:00:18 CEST