How can I evaluate an array of multidimensional functions in Matlab?

Question

I have a 6x3 array of functions, dens, in Matlab, in which each function has a two-dimensional vector z as input. I need to evaluate these functions at z=[2 3], all at the same time; I have tried

ev_dens = @(z) cellfun(@(myfun) myfun(z),dens,'UniformOutput',false);
z =[2 3];
ev_dens(z)

but I got this error

??? Index exceeds matrix dimensions.
Error in ==> @(myfun)myfun(z)
Error in ==> @(z)cellfun(@(myfun)myfun(z),dens,'UniformOutput',false)

Could you help me?

I am unable to reproduce the problem, what is dens? Using some dummy data (dens(1:6,1:3)={@(x)([x(2),x(1)+x(2)])}) I don't get any error. — Daniel
– Daniel, Commented May 6, 2014 at 11:24

Dan · Accepted Answer · 2014-05-06 11:47:32Z

2

Using the following example data:

f{1,1} = @(z)([z(1),z(1)])
f{1,2} = @(z)([z(1),z(2)])
f{2,1} = @(z)([z(2),z(1)])
f{2,2} = @(z)([z(2),z(2)])

z = [2,3];

Your method works fine:

cellfun(@(F)F(z), f,'UniformOutput',false)

So it sounds like perhaps you have an error in one of your functions in dens. Try a nested for loop and see where you error:

for ii = 1:size(dens,1)
    for jj = 1:size(dens,2)
        dens{ii,jj}(z)
    end
end

and then check the values of ii and jj after you get your error, the function at dens{ii,jj} has an error in it.

In order to correct for the issue you mention in the comments (i.e. some of your cell elements are empty (i.e. []), run this function first to convert your empty cells into function that output empty cells:

dens(cellfun(@isempty,dens)) = {@(z)([])}

edited May 6, 2014 at 11:47

answered May 6, 2014 at 11:27

Dan

45.8k20 gold badges98 silver badges169 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Star Over a year ago

Thanks for your help; I have finally discovered the problem in my code: inside the array of functions I have some cells=[]. The problem is that I cannot predict where the [] cells will be and I cannot delete them. Do you know a way to overcome this issue? I would like to get 0 or [] in arrayfun in correspondence to these cells.

Dan Over a year ago

how about calling this first dens(cellfun(@isempty,dens)) = {@(z)([])}

Collectives™ on Stack Overflow

How can I evaluate an array of multidimensional functions in Matlab?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related