In message <

[hidden email]>

Albert Chan <

[hidden email]> wrote:

>Using while do loop is a bad idea, as it can easily get

>into infinite loop. It would be better if the solver "give-up"

>if it cannot converge within some maximum iterations.

>

>Another problem is the df function.

>A symbolic df function may be hard to get (or messy)

Yes, there are lots of ways to find fixed points without using

derivatives.

>Even the f function may be hard to get.

>Most engineering problem involve simultaneous system of

>equations, which were hard to simplify into a single f

>

>It is much easier using, say TK solver, instead of Lua.

>Instead of a bunch of equations for solving different variable,

>Just leave the input field(s) blank (or guess values), and type !

>

>Excel spreadsheet solver is another option.

I agree with you Albert. If what you want is just a number then use a package,

where the gotchas have been properly sorted. If what you want is understanding

(not clear from original question) then reinvent wheel. Educational administrators

frequently fail to understand that learning means wheel-reinvention, but that

research students need to build on other people's efforts, i.e. packages. So

the administrators should be the last people to have a say in what software to use.

--

Gavin Wraith (

[hidden email])

Home page:

http://www.wra1th.plus.com/