Re: FindRoot question
- To: mathgroup at smc.vnet.net
- Subject: [mg29906] Re: FindRoot question
- From: klaus at biosci.cbs.umn.edu (Chris Klausmeier)
- Date: Wed, 18 Jul 2001 02:08:48 -0400 (EDT)
- References: <9j05h0$esi$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Just a follow-up on my own question. Part of the problem was that I
was calling another homemade function that used FindRoot from within
FindRoot. Problems arose when the inner FindRoot got non-numeric
values for its options. From other messages I found that using
_?NumberQ for the inside function should help, but I was passing my
options as a list, which would not make it by _?NumberQ. _?ListQ
didn't help either, because {x,y} counts as a list as well as {1,2}.
I ended up writing the following test for a list of numbers, which
helped.
ListOfNumbersQ[list_]:=Module[{n,ret},
If[ListQ[list]==False,ret=False,
n=Length[list];
ret=True;
Do[
If[NumberQ[list[[i]]]==False,ret=False]
,{i,1,n}];];
Return[ret]; ];
Thus:
In[21]:=
ListOfNumbersQ[{1,2}]
Out[21]=
True
In[23]:=
ListOfNumbersQ[{x,y}]
Out[23]=
False
My inside function then begins:
neq[xopts_?ListOfNumbersQ,ni_]:=Module[ ...
-- Chris