Vectrorized Calls of function handles, which are stored in a cell

Question

I would like to know if there is a way to vectorize the calls of different function handles, which are stored in a cell array and have of course input values themselves. I basically have a model, which looks like:

    MyModel=cell(2,1);
    MyModel{1}=@(a,b) a+b;
    MyModel{2}=@(a,b) a-b;
    a=[1,2];
    b=[2,1];
    ModelNumber=[1,2];

Now I would like to call MyModel{ModelNumber(1)} at a(1) and b(1) and MyModel{ModelNumber(2)} at a(2) and b(2). Of course it can be done with a for loop. However, the real thing will take a lot of time, if I use a loop. So is there a way to vectorize the problem in a way that something like

    MyModel{ModelNumber(:)}(a(:),b(:))

works? I already looked at cellfun, but couldn't find an answer.

Thanks in advance! Ingo

There is probably no reason to use cellfun here http://stackoverflow.com/questions/12522888/arrayfun-can-be-significantly-slower-than-an-explicit-loop-in-matlab-why — Daniel, Dec 01 '15 at 10:10
Thanks for your reply. However, I cannot see where structfun may help. Both, `cellfun` and `structfun` apply a function to all elements of a cell or struct. But i have a load of different functions. — Ingo, Dec 01 '15 at 10:12
@ingo: your original title had a typo in it, there you wrote functions in a struct while the question is about functions in cells. I corrected the title. Structfun probably won't help here. — Daniel, Dec 01 '15 at 10:18
@Daniel, Oh sorry, of course I was talking about cells,thanks — Ingo, Dec 01 '15 at 10:22
@Daniel `cellfun` is just nice as shorthand. This doesn't look like performance is a major issue. — Dan, Dec 01 '15 at 10:34
@Ingo try using `cellfun` like so: http://stackoverflow.com/a/33144578/1011724 — Dan, Dec 01 '15 at 10:35
@dan: performance seems to be the issue here "However, the real thing will take a lot of time, if I use a loop.". Don't see cellfun solving this. — Daniel, Dec 01 '15 at 10:45
@Daniel I did not read properly. Sure, `cellfun` is not going to outperform a loop! — Dan, Dec 01 '15 at 10:57

score 0 · Answer 1 · answered Dec 01 '15 at 15:39

As discussed in the comments, simply using cellfun won't increase the performance over a simple for loop. Thus a for loop is the best solution for the generic case you described above.

I would expect a good performance from a for loop in this case, thus if your solution is to slow you may put it into the question and we will see if it could be improved.

Vectrorized Calls of function handles, which are stored in a cell

1 Answers1