Handling function inputs in Matlab

Question

Say I have a function

function u = somefxn(f,n)

where f is some function, say f = pi^2*sin(pi*x), and n is the number of discretizations (let n = 1024) on the interval $[0,1]$. In my code I've written

h = 1/n %n = 1024
x = 0:h:1 %discretizations

But what if the user uses y or z in the function instead of x? How do I handle that uncertainty?

Please let me know if this isn't clear. I'm rather new to Matlab.

Answer 1

1. The function f has (should have?) its own local variable, the name of which is independent of the calling scope.

2. It's much better to use x = linspace(0,1,n+1) than x = 0:1/n:1 because the latter is susceptible to rounding error.

Answer 2

I think I get your point, which this answer hasn't got.

Do you mean literally something like

x=1:0.1:10;
f=(pi^2)*sin(pi*x);

?

Then f is no longer a function. It is just a variable containing the result of the function applied to the x that you already have. In other words, your function has already been evaluated.

In this case, the answer to your question is that you don't need to do anything : f simply does not know about x, or other variable.

Depends on what's the exact code in question.