Re: Passing parameters to fsolve function - new syntax?

[Paul Kienzle]

Correction: you can also call the current fsolve with a string 
expression.

E.g.,

octave:1> function y=f(x,a,b,c), y = a*x.^2+b*x+c; end
octave:2> fsolve("f(x,1,-2,-3)",0)
ans = -1.0000

- Paul

On Oct 5, 2005, at 6:40 AM, Paul Kienzle wrote:

> Looking at the source to src/DLD-FUNCTIONS/fsolve.cc and 
> src/variables.cc, it looks like extract_function will only look for 
> functions defined by string name.
>
> On Oct 5, 2005, at 4:27 AM, Aivo Jürgenson wrote:
>
> > Hello,
> >
> > I have a function f(x,a,b,c), which I would like solve for variable 
> > x, so that f(x,a,b,c)=0, where a,b,c are parameters, which are known 
> > at the time of solving.
> >
> > However, current fsolve function in Octave only supports one-variable 
> > functions. I suppose there is a work-around to declare specific 
> > global variables and then giving values to those variables before 
> > calling the fsolve function, but this doesn't seem to be a clean way 
> > of organizing this.
> >
> > The fsolve FIX in the octave-forge package seems to expand this 
> > functionality, but I'm not able to compile it. Also, the status of 
> > this FIX seems to be unclear, as in the development mailing list 
> > message 
> > http://sourceforge.net/mailarchive/message.php?msg_id=11922522:
> >
> > Paul Kienzle, in May, 2005:
> >
> > > I have no interest in maintaining this function.  I am removing it 
> > > from
> > > the build system for now, and will purge it completely if nobody 
> > > steps
> > > forward to update it.
> > >
> > > IIRC, the purpose of this function is to pass extra arguments to
> > > fsolve, but we can do this now with the new syntax:
> > >
> > >         @(x) f(x,a,b,c)
> > >
> > > - Paul
> >
> > Could somebody explain this new syntax? I would be happy to use this 
> > new and official way of passing extra arguments to fsolve, but I'm 
> > not been able to find any examples of doing it.
> >
> > Aivo Jürgenson, address@hidden
>
>
>
> -------------------------------------------------------------
> Octave is freely available under the terms of the GNU GPL.
>
> Octave's home on the web:  http://www.octave.org
> How to fund new projects:  http://www.octave.org/funding.html
> Subscription information:  http://www.octave.org/archive.html
> -------------------------------------------------------------




-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------