Re: Re: Hold problems with FindRoot

*To*: mathgroup at smc.vnet.net*Subject*: [mg57091] Re: [mg57073] Re: Hold problems with FindRoot*From*: Chris Chiasson <chris.chiasson at gmail.com>*Date*: Sun, 15 May 2005 03:03:44 -0400 (EDT)*References*: <428457A1.3020501@bjornerstedt.org> <200505140858.EAA09467@smc.vnet.net>*Reply-to*: Chris Chiasson <chris.chiasson at gmail.com>*Sender*: owner-wri-mathgroup at wolfram.com

Try changing the definitions of f and g, via a PatternTest, so that they are only defined for numeric arguments. f[x_?NumericQ,y_?NumericQ]=blahblah1 g[x_?NumericQ,y_?NumericQ]=blahblah2 On 5/14/05, Jonas Björnerstedt <lists at bjornerstedt.org> wrote: > Hello again, > > There was a small mistake in my previous posting. It should have said: > > FindRoot[Evaluate[{f[x,y]==0, g[x,y]==0}],{{x,1},{y,1}}] > > where f and g are functions that work correctly. Trying to solve one > equation for two unknowns would cause other problems than I am currently > having. > > Jonas. > > Jonas Björnerstedt wrote: > > > Hello all, > > > > I have problems getting FindRoot to evaluate the equations it > > evaluates, despite using Evaluate on the equations. I have a rather > > complex function f[x,y] that works correctly with individual values x > > and y. Evaluating the following expression does not work however. > > > > FindRoot[Evaluate[f[x,y]==0],{{x,1},{y,1}}] > > > > When evaluating, I get similar errors as when I evaluate f without > > inserting values for x and y. I can also do a Plot3D on f without > > using Evaluate. > > > > Does anybody have an idea what the problem is? > > > > Jonas > > > > -- Chris Chiasson http://chrischiasson.com/ 1 (810) 265-3161

**References**:**Re: Hold problems with FindRoot***From:*Jonas Björnerstedt <lists@bjornerstedt.org>