A basic question about RecurrenceTable - warning messages
- To: mathgroup at smc.vnet.net
- Subject: [mg122235] A basic question about RecurrenceTable - warning messages
- From: victorphy <vbapst at gmail.com>
- Date: Fri, 21 Oct 2011 07:28:36 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
Hello,
I have a small and basic question about RecurrenceTable.
I would like to solve f(x,a)==0 where x is the unknown and a is a
parameter. As f has several zeros I want to follow one zero when
varying a.
Thus I write something like that :
f[x_,a_] := -(x - a)^3 + (x - a)
soltest[a_, b_] := x /. FindRoot[f[x, a], {x, b}]
RecurrenceTable[{a[n + 1] == soltest[n/10, a[n]], a[0] == -1}, a, {n,
10}]
I get the correct output but a lot of warning messages :
FindRoot::srect: "Value a[n] in search specification {x,a[n]} is not a
number or array of numbers
ReplaceAll::reps: "{FindRoot[f[x,n/10],{x,a[n]}]} is neither a list of
replacement rules nor a valid dispatch table, and so cannot be used
for replacing
Is there something that I am doing wrong ? Or is it just normal ?
Thank you very much for your answers.
Victor