Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2001
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2001

[Date Index] [Thread Index] [Author Index]

Search the Archive

lists w/o double brackets

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31436] lists w/o double brackets
  • From: Gavin K Brennen <gbrennen at unm.edu>
  • Date: Mon, 5 Nov 2001 03:48:19 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Hello,

I am using the function FindRoot with a large number of simultaneous equations.

	FindRoot[eqs,initialvals]

I have a function for generating the equations which works fine as a list
input in FindRoot, however I am having difficulty creating a function for
generating initialvals that will be accepted by FindRoot.  The problem
seems to be that FindRoot demands a format

	FindRoot[{eq1,eq2,...,eqn},{var1,val1},{var2,val2},...,{varn,valn}]

the variables and initial values of which must appear as a list without
double brackets.  The function I have for generating the initial values
always outputs the list as follows


	Input
		initialvals
	Output
		{{var1,val1},{var2,val2},...,{varn,valn}}.

Note the double brackets which FindRoot will not accept.
I have tried using

  initialvals2=StringReplace[ToString[initialvals], {"{{" -> "{", "}}" ->
"}"}]

which eliminates the double brackets, however FindRoot will not accept
stings as input for the variables and upon converting back to an Expression
using

	ToExpression[initialvals2]

the double brackets return.

Is there a solution to this without having to manually cut and paste the
output of my expression for initialvals without the double brackets into
FindRoot?

Thanks much,

Gavin
gbrennen at unm.edu




  • Prev by Date: Re: how to limit digits?
  • Next by Date: Re: Clearing Subscripted Variables?
  • Previous by thread: Re: Storing Data into Excel - Pls Help ...
  • Next by thread: Re: lists w/o double brackets