Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Michael Okuntsov <okuntsov.mikhail@yandex.ru>
Newsgroups: comp.graphics.apps.gnuplot
Subject: Re: fitting for Bateman equation returns NaN
Date: Thu, 3 Nov 2016 17:11:13 +0700
Organization: A noiseless patient Spider
Lines: 13
Message-ID: <nvf2f7$5ci$1@dont-email.me>
References: <c9696e77-4fc9-4466-9175-bff4ac3d6ef0@googlegroups.com> <nvcvov$qad$1@dont-email.me> <65025da6-a456-46d5-b987-2b6d8dcbc692@googlegroups.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Thu, 3 Nov 2016 10:10:47 -0000 (UTC)
Injection-Info: mx02.eternal-september.org; posting-host="3befe2ee528d81696d442400693365d9"; logging-data="5522"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19bmuk+ovTKuDVqpmX5gHR4"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0
In-Reply-To: <65025da6-a456-46d5-b987-2b6d8dcbc692@googlegroups.com>
Cancel-Lock: sha1:OWB6QijTKvFyUqHXXUP90Pq4764=
Xref: csiph.com comp.graphics.apps.gnuplot:3431


> Hi Michael,
>
> Thank you! it works great now. Why do we define B, though, and is the -0.1 arbitrary? What do I define N or M as, if I want to fix A, B and fit via N or M?
>
> Thanks :)
>

I've tried different initial values of B, and iterations converge if the 
value is about -0.1 or 0.1. The default value for initial parameters in 
gnuplot is 1, and it seems that iterations disperse with that value. 
Notice that there is also convergence if B=-1, so it seems that your 
function has at least two local extremes.