88cd16a4e3c70d82567c96c1ffc277ef8ea87a3f,pymc3/step_methods/hmc/hmc.py,HamiltonianMC,astep,#HamiltonianMC#Any#,59

Before Change

        q = q0
        p = self.H.pot.random()  // initialize momentum
        initial_energy = self.compute_energy(q, p)
        q, p, current_energy = self.leapfrog(q, p, e, n_steps)
        energy_change = initial_energy - current_energy
        return metrop_select(energy_change, q, q0)[0]

After Change

        p0 = self.potential.random()
        start = self.integrator.compute_state(q0, p0)

        if not np.isfinite(start.energy):
            raise ValueError("Bad initial energy: %s. The model "
                             "might be misspecified." % start.energy)

        state = start
        for _ in range(n_steps):
            state = self.integrator.step(e, state)

Instances