Why do the numpy and random modules give different random numbers for the same seed?

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悲&欢浪女
悲&欢浪女 2021-01-20 01:01

For the same seed, why does random.random() produce different random values when compared to numpy.random(). My understanding is that they both use the Mersenne Twister to g

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  • 2021-01-20 01:49

    The random module and numpy.random both use a mt19937 to generate random numbers. Because of this, we can copy the state of one from one generator to the other to see if they have the same underlying implementation.

    import random as rnd
    import numpy as np
    
    # seed numpy
    np.random.seed(1)
    
    # get state from numpy
    state = [int(s) for s in list(np.random.get_state()[1])]
    state.append(624)
    state = tuple(state)
    state = (3, tuple(state), None)
    
    # set state for python 
    rnd.setstate(state)
    
    print(rnd.random())
    print(np.random.rand())
    

    0.417022004702574

    0.417022004702574

    It looks like the mt19937 engine used gives equivalent results if the state is manually set to be the same. This seems to imply the seed function are implemented differently.

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