In your while loop:
while number_of_repeats <= 3
The condition "number_of_repeats <= 3" is always true because the for-loop that it is contained in defines number_of_repeats as 1 to begin with. Hence the infinite loop.
If you only want the whole thing to run 3 times, then just get rid of the while loop entirely. E.g.,
for number_of_repeats = 1 : 3 %to repeat it 3 times
for i = 0 : Time_steps %during each of the 3 times
statement to perform stuff for i= 0: Time Steps
end
end
