dq.solver.Kvaerno3
Kvaerno3(
rtol: float = 1e-06,
atol: float = 1e-06,
safety_factor: float = 0.9,
min_factor: float = 0.2,
max_factor: float = 5.0,
max_steps: int = 100000,
)
Kvaerno's method of order 3 (adaptive step size and implicit ODE solver).
This method is suitable for stiff problems, typically those with Hamiltonians or Liouvillians that have eigenvalues spanning different orders of magnitudes. This is for instance the case with problems involving high-order polynomials of the bosonic annihilation and creation operators, in large dimensions.
This solver is implemented by the Diffrax
library, see diffrax.Kvaerno3
.
Warning
If you find that your simulation is slow or that the progress bar gets stuck,
consider switching to double-precision with
dq.set_precision('double')
. See more details in
The sharp bits 🔪 tutorial.
Parameters
-
rtol
–
Relative tolerance.
-
atol
–
Absolute tolerance.
-
safety_factor
–
Safety factor for adaptive step sizing.
-
min_factor
–
Minimum factor for adaptive step sizing.
-
max_factor
–
Maximum factor for adaptive step sizing.
-
max_steps
–
Maximum number of steps.
Supported gradients
This solver supports differentiation with
dq.gradient.Autograd
and
dq.gradient.CheckpointAutograd
.