Something changed in `pytensor > 2.12.3` (and thus `pymc > 5.6.1`) that makes my `pytensor.gradient.grad` call get stuck - any ideas?

Questions v5
21

You shouldn’t need to be passing around rngs, because your function is completely deterministic.

You should not be getting non-square matrices inside the log_jcd_elem function. You want to arrange things to be something like this:

def log_jcd_elem(A, x):
    jac =  tg.jacobian(A, x) #(2, 2)
    sign, logdet = pt.linalg.slogdet(jac)
    return logdet

Scan iterates over the left-most dimension of the inputs, so as long as f_inv_x is 10, 2 and x is 10, 2, you just need to:

jacs, _ = pytensor.scan(log_jcd_elem, sequences=[f_inv_x, x])

If that doesn’t work, I’ll take a more careful look at the gist and see if I can figure something out.

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