Hi Anna,
The below code snippet can accomplish the task. It fits all the models specified it 'fit_func' array and records the R^2 value in a vector. Finally, the model with the highest R^2 value can be easily extracted.
fit_func={'poly1','poly2','poly3','poly4','poly5','poly6','poly7','poly8','poly9'};
rsquare_values=zeros(length(fit_func),1);
for i=1:length(fit_func)
[linear1, gof]=fit(M1,M2,fit_func{i});
rsquare_values(i)=gof.rsquare;
end
[best_rsquare,index] = max(rsquare_values);
best_model = fit_func(index);
best_rsquare - highest R^2 value corresponding to the best model.
best_model - contains the model with the highest R^2 value.
