mutation.py

def mutate(dna, mutation_sigma, mutation_rate):
    
    # If random dice roll (between zero and one) is less than mutation
    # rate (between zero and one) then inject noise into the dna.
    if np.random.random_sample() < mutation_rate:
        
        # The noise is scaled by the mutation_sigma.
        dna += np.random.standard_normal(size=dna.shape) * mutation_sigma

    return dna