How to fix a randomly generated sample in Matlab after making some changes to the code?

I need to have the same sample (same data points) that was generated from a large set of data in order to make some comparisons as I vary some conditions or parameters. However, the sample changes after each Matlab run. My current sampling is based on the use of "randperm" or sampling without replacement.

Any help would e greatly appreciated. Thanks.

Answer 1

[Stephen23]

You can use rng to control the random number generation, for example (from that link):

s = rng;
x = rand(1,5)
x =
    0.8147    0.9058    0.1270    0.9134    0.6324
rng(s);
y = rand(1,5)
y =
    0.8147    0.9058    0.1270    0.9134    0.6324

You can also use the seed option to reset the random numbers to a known starting point:

rng(N)

More information on this topic:

http://www.mathworks.com/help/matlab/math/generate-random-numbers-that-are-repeatable.html

http://www.mathworks.com/help/matlab/math/why-do-random-numbers-repeat-after-startup.html

[Summer]

Thanks!