def set_use_correlated_random_number(v: bool):
    """
        | There is a bias-variance trade off in the backward pass.
        | If the forward pass and the backward pass are correlated
        | the gradients are biased for L2 loss.
        | (E[d/dx(f(x) - y)^2] = E[(f(x) - y) d/dx f(x)])
        |                      = E[f(x) - y] E[d/dx f(x)]
        | The last equation only holds when f(x) and d/dx f(x) are independent.
        | It is usually better to use the unbiased one, but we left it as an option here
    """
    global use_correlated_random_number
    use_correlated_random_number = v
