quantax.optimizer.SR

class quantax.optimizer.SR(state: Variational, hamiltonian: Operator, imag_time: bool = True, solver: Callable | None = None)

Stochastic reconfiguration (SR). This optimizer automatically chooses between SR and MinSR based on the the number of samples and parameters.

__init__(state: Variational, hamiltonian: Operator, imag_time: bool = True, solver: Callable | None = None)

Parameters:

• state – Variational state to be optimized.

• hamiltonian – The Hamiltonian for the evolution.

• imag_time – Whether to use imaginary-time evolution, default to True.

• solver – The numerical solver for the matrix inverse, default to auto_pinv_eig.

Methods

__init__(state, hamiltonian[, imag_time, solver])
get_Ebar(samples)	Compute \(\bar \epsilon\) for given samples.
get_Obar(samples)	Calculate \(\bar O = \frac{1}{\sqrt{N_s}}(\frac{1}{\psi} \frac{\partial \psi}{\partial \theta} - \left< \frac{1}{\psi} \frac{\partial \psi}{\partial \theta} \right>)\) for given samples.
get_step(samples)	Obtain the optimization step by solving the equation \(\bar O \dot \theta = \bar \epsilon\) for given samples.
solve(Obar, Ebar)	Solve the equation \(\bar O \dot \theta = \bar \epsilon\) for given \(\bar O\) and \(\bar \epsilon\).

Attributes

VarE	Energy variance \(\left< (H - E)^2 \right>\) of the current step.
energy	Energy of the current step.
hamiltonian	The Hamiltonian for the evolution.
holomorphic	Whether the state is holomorphic.
imag_time	Whether to use imaginary-time evolution.
state	Variational state to be optimized.
vs_type	The vs_type of the state.