Re: fsolve features

[John W. Eaton]

On  5-Jul-1999, Francesco Potorti` <address@hidden> wrote:

| It is easy to work around this.  Maybe you are suggesting that a workaround
| is nt what you would like to have?
|    
|    [x,RC]= fsolve(f='x^2 +1',randn(1)); #>V2.0.14
|        #NOTE: prior to V2.0.14 , you have to  define  f  explicitely:
|        #function y=f(x) y=x^2+1; end
|        #[x,RC]=fsolve('f',randn(1))
| 
| !!!  Where is this documented?

I'm afraid it is not documented yet.  It is something new in the 2.1.x
sources.  For built-in functions that require user-supplied functions,
you will be able to specify either the name of a function, or an
expression (as a string) to use in place of the user-supplied
function.

In the case of fsolve, Octave compiles a temporary function like this:

  function y = __fsolve_fcn__ (x)
    y = YOUR_EXPRESSION_INSERTED_HERE;
  endfunction

This is not very flexible (you can't supply a complicated function
body as a string) but it is convenient for things that can be stated
as simple expressions.

I believe that something similar is now possible in Matlab.

jwe



---------------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.  To ensure
that development continues, see www.che.wisc.edu/octave/giftform.html
Instructions for unsubscribing: www.che.wisc.edu/octave/archive.html
---------------------------------------------------------------------