Thread Subject: inserting a value in a function, but how?

Hi

How can I insert a value to a function?

ie.

console
>>fun(log(x),2,0.01)

m-file
function out = fun(f,x,h)
% f should be ln(x), x should be 2 and h should be 0.01

v = f(x+h)-f(x)
% v should be ln(2+0.01)-ln(2), ans is 0.0049875

But it doesn't work.

"A " <amutka@welho.com> wrote in message <fvv2c7
$3mq$1@fred.mathworks.com>...
> Hi
>
> How can I insert a value to a function?
>
> ie.
>
> console
> >>fun(log(x),2,0.01)
>
> m-file
> function out = fun(f,x,h)
> % f should be ln(x), x should be 2 and h should be 0.01
>
> v = f(x+h)-f(x)
> % v should be ln(2+0.01)-ln(2), ans is 0.0049875
>
> But it doesn't work.

doc function_handle

% see the first example

"someone " <someone@somewhere.net> wrote in message
<fvv4p4$58t$1@fred.mathworks.com>...
> "A " <amutka@welho.com> wrote in message <fvv2c7
> $3mq$1@fred.mathworks.com>...
> > Hi
> >
> > How can I insert a value to a function?
> >
> > ie.
> >
> > console
> > >>fun(log(x),2,0.01)
> >
> > m-file
> > function out = fun(f,x,h)
> > % f should be ln(x), x should be 2 and h should be 0.01
> >
> > v = f(x+h)-f(x)
> > % v should be ln(2+0.01)-ln(2), ans is 0.0049875
> >
> > But it doesn't work.
>
> doc function_handle
>
> % see the first example
>

I don't have matlab at home so I can't access the doc. Could
you post the example here?

In article <fvv6mu$qri$1@fred.mathworks.com>, A <amutka@welho.com> wrote:

>I don't have matlab at home so I can't access the doc. Could
>you post the example here?

google site:mathworks.com for the term you are looking for.


--
  "To burn always with this hard, gem-like flame, to maintain this
  ecstasy, is success in life." -- Walter Pater

In article <fvv2c7$3mq$1@fred.mathworks.com>, A <amutka@welho.com> wrote:

>How can I insert a value to a function?

>>>fun(log(x),2,0.01)

>m-file
>function out = fun(f,x,h)
>% f should be ln(x), x should be 2 and h should be 0.01

>v = f(x+h)-f(x)
>% v should be ln(2+0.01)-ln(2), ans is 0.0049875

That can only work if you have defined x as a sym. You have posted
several times before with basically the same problem and as best
I recall, none of those postings have had any indication that you
have the symbolic toolbox to work with.

But you don't need the symbolic toolbox if you modify very slightly:

>>>fun(@log, 2, 0.01)

And the m-file you show would stay exactly the same.
--
  "They called it golf because all the other four letter words
  were taken." -- Walter Hagen