BLOCKER: How to seed randoms with entropy ?

[rebcabin]

This is a real BLOCKER but I hope easy to fix ? I need randoms that change from run-to-run. Our LPython random produces the same result every run.

from random import random

print(random())  ########### PRODUCES SAME RESULT EVERY RUN ##########

# BUT, how to seed with time-of-day or internet noise
# or some other sort of variable entropy?

# NO WORK from random import seed

[certik]

As a quick fix, let's do:

from lpython import init_random
from random import random
init_random()
print(random())

Where the init_random function is our own function, doing nothing in CPython mode, but initializing the random number generator for LPython mode. That should unblock Brian.

Later we can figure out whether to call init_random() automatically in the main program and whether to always call it, or only if the user calls random, etc. (I think CPython somehow initializes the random number generator automatically). That's lower priority.

[rebcabin]

Let init_random have an optional argument (or something like that) so I can seed the RNG for the cases where I do not want entropy, i.e., where I do want deterministic pseudorandoms.

[rebcabin]

Something that's more fitting is "seed" https://docs.python.org/3/library/random.html#bookkeeping-functions Even a partial implementation of that will be a great unblocker :)

…

On Wed, Jul 5, 2023 at 1:29 PM Ondřej Čertík ***@***.***> wrote: As a quick fix, let's do: from lpython import init_random from random import random init_random() print(random()) Where the init_random function is our own function, doing nothing in CPython mode, but initializing the random number generator for LPython mode. That should unblock Brian. Later we can figure out whether to call init_random() automatically in the main program and whether to always call it, or only if the user calls random, etc. That's lower priority. — Reply to this email directly, view it on GitHub <#2110 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABSRRZ4CVN3HBASK4WSO4DXOXFEPANCNFSM6AAAAAAZ7MNVHU> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[OmarMesqq]

Hello, I was thinking of grabbing this issue, and I already thought of a way of doing so with C++ random. I already have the code inside libasr in rng.cpp, but can't link it correctly.

I set the SRC in CMakeLists.txt to include my file and exported it with extern "C" , but still doesn't work.

Anyone got any tips?

[certik]

@OmarMesqq go ahead and submit a PR with what you have, and then we'll help improve it.

[certik]

I think @rebcabin is not blocked by this anymore, so I removed the BLOCKER tag.

[certik]

This issue will be fixed by #2318.

There is another issue that the random numbers do not appear random, which is a separate issue: #2382.