Re: How to allow for a parameter when callling another function

[Olaf Till]

On Tue, May 03, 2011 at 06:09:24PM -0700, clustro wrote:
> Hi there,
> 
> I am programming a function that minimizes another function. I call the
> function like this:
> 
> Data = mcsa('ackley',x0)
> 
> where:
> 
> Data is the output (not important)
> 'ackley' is a function I wish to minimize (I have others; this is just an
> example)
> x0 is the initial-geuss vector.
> 
> Now, the ackley function, among others, can be altered by a parameter, n.
> Currently, if I want to change n, I must manually go into ackley.m, change
> it, and run the code again.
> 
> It would be more convenient if I could do it all in one shot. I tried
> changing ackley to be y = ackley(x,n)

> (and commented out n in the rest of the code),

I don't understand what you mean by this ... why have you commented it
out?

> and ran the code like this:
> 
> Data = mcsa(@(x) ackley(x,n),x0)

That is normally a good way, but you seem to have made some mistake
which is hard to guess from the information you provide.
 
> But I get:
> 
> error: subscript indices must be either positive integers or logicals.
> 
> The error is on the first line where I use the "feval" function. Changing
> @(x) ackley(x,n) to a string did not work either; Octave just didn't find
> the file then.

I suggest you show us at least the header and this first line of your
function, and tell us what is in the variable 'n'.

Olaf