How do I create an array of a function output?

How do I create an array of a function output? Each attempt I've tried it overwrites the value in the array and returns a 1x1 array with the final value calculated as it's value.

I've seen nested list functions or push functions? Which is the best for the below case and how do I implement it?

Apologies if this is a simplistic question, just struggling with this problem.

My function is:

>> m=0:1:3
>> n=0:1:4
>> for a=m
for b=n
res=ack(a,b)
end
end
function res=ack(m,n)
      if m==0
        res = n+1;
      elseif m>0 && n==0
        res = ack(m-1,1);
      elseif m>0 && n>0
        res = ack(m-1,ack(m,n-1));
      end
end

[David Fletcher]

Essentially your problem is very similar to the answer I provided for

https://uk.mathworks.com/matlabcentral/answers/384744-nested-for-loops-help#answer_307026

Maybe not the 'best' way to do it, but it is pretty much the answer to the problem you are outlining

Answer 1

[Stephen23]

Method one: nested loops and indexing

m = 0:3;
n = 0:4;
out = nan(numel(m),numel(n));
for km=1:numel(m)
    for kn=1:numel(n)
        out(km,kn) = ack(m(km),n(kn));
    end
end

giving:

out =
     1     2     3     4     5
     2     3     4     5     6
     3     5     7     9    11
     5    13    29    61   125

Method two: arrayfun:

>> [M,N] = ndgrid(m,n);
>> out = arrayfun(@ack,M,N)
out =
     1     2     3     4     5
     2     3     4     5     6
     3     5     7     9    11
     5    13    29    61   125

[FortuitousMonkey]

Both work for me.

Thanks for helping.

[Cedrick De Block]

hello excuse me,

in your fist example I have a problem with "ack"

matlab doesn't reconise it, is it a function?

Answer 2

[Walter Roberson]

See https://www.mathworks.com/matlabcentral/answers/378143-why-does-my-for-loop-generate-the-inproper-matrix-it-spits-out-way-more-zeros-then-there-should-be#answer_301030

[FortuitousMonkey]

Could you help me implement this in my code, please? I am drawing a blank (relatively new to matlab).