Apply function on all matrix elements

Question

I want to apply a function on each element in a matrix. I've written the following code:

function p = an(x)
    p= x + 1;
end

The matrix is for example:

B = [1 2 3; 3 4 5; 6 7 8]

When I try to do this:

arrayfun(@an , B(1, :) , B(2, :), B(3, :))

I get this error:

??? Error using ==> arrayfun
Undefined function or method 'an' for input arguments of type 'double'.

I can't understand why. How I can fix it? Is there a easier way to do it?

Solution

Main problem

Undefined function or method 'an' for input arguments of type 'double'.

This means that MATLAB doesn't recognize your function an. Make sure that an is implemented in a separate m-file called an.m, and that it is located in your current working directory.

Additional problem

I can see that your arrayfun syntax is flawed. Once you solve your current problem, I predict that you will encounter another error message:

??? Error using ==> an
Too many input arguments.

The problem is that function an accepts only one input argument, but you're passing three arguments in arrayfun. Instead, either pass only one argument, for example:

arrayfun(@an, B);

or modify an to accept three arguments, for example:

function p = an(x, y, z)
    p = x + y + z

I'm not sure what you're trying to achieve, so it's up to you to choose.

Comments

[HebeleHododo]

What is your desired output?

[user1943029]

Thank you very much! it works

[user1943029]

I have one more question: if i will change the "an" function to: function ans = an(x) if x == 1 ans = x+1; else ans = x+2; end end How can I apply this function on each cell of the matrix? (I've tried to write: arrayfun(@an,B) but it doesn't work. thank you .

[Eitan T]

@user1943029 you're using the variable ans which is already reserved keyword. Use another name and it should work.

[user1943029]

It doesnt work with another name. Is there another way to solve it?

[Eitan T]

Can you give more details about "it doesn't work"? Do you get an error message?