class_docstr: Step size adaptation state.
code: def opt_step_size(self):
      return jnp.exp(self.opt_state.state)
  
imports: import functools
  import typing
  from typing import Any, Callable, Iterable, NamedTuple, Optional
  import numpy
  from fun_mc import backend
  from fun_mc import fun_mc_lib
  from fun_mc import malt
  from fun_mc import sga_hmc
  from fun_mc.malt import *
  from fun_mc.sga_hmc import *
label_desc: Use image node_id 1 for calling the StepSizeAdaptationState obj's underlying member method code with example usage: obj.opt_step_size() and returns: jnp