random function in C++ and Matlab

Question

I have a code written in Matlab , and I wrote it in C++, but I don't this don't give the same results.

The problem is that I use random function in 3 parts of the code, when I make the random functions fixed , both codes gave the same output.

If any body have any ideas please help me.

Answer 1

The implementation of the rand functions will differ.

You can control the Matlab version through rng .

On the C++ end, I suggest using the functionality in (C++11) <random> (or use Boost's version if your environment is lacking decent C++11 library support) . I can't test right now, but it seems like both sides support the Mersenne Twister. With a bit of luck, the implementation will generate the same numbers if you choose the same seed.

I can't test this now as I don't have Matlab here.

Answer 2

It is because of rand() function give you same numbers. It is better to use srand (time(NULL)); before you call rand() function. srand (time(NULL)); makes rand() to produce different outputs.

For using srand (time(NULL)); function, you should add #include <time.h> or #include <ctime> in your code.