iterate names for LinearModel fit Objects

I need to iterate through a large number of LinearModel fit Objects and have them stored in a logical way, preferably through an indexing method, e.g. model{x,y}. Less preferable is eval(), which I have tried and in any case is not working. I get the error Index exceeds matrix dimensions.

"Index exceeds matrix dimensions." - although the string expression works just fine outside of eval.

counter = 48;
str=strcat('model',+num2str(counter)); % Dynamic variable name
str1 = strcat(str,'=fitlm(tbl,modelspec)');
eval(str1)

Ideally I wanted to do, while iterating through x

model{x,y} = fitlm(tbl,modelspec)

But the error I get is

"Assignment using {} is not allowed for a FitObject."

Answer 1

[Edward Byers]

Managed to fix this by assigning a cell structure

model = cell(3,3) % Pre-assign a cell structure
for x=1:3
    for y=1:3
        model{x,y} = fitlm(tbl,modelspec);
    end
end