class_docstr: Covariance Matrix Adaptation Evolution Strategy.
  
  Note:
      The CMA-ES method can hardly learn a successful policy even for
      simple task. It is still maintained here only for consistency with
      original rllab paper.
  
  Args:
      env_spec (EnvSpec): Environment specification.
      policy (garage.np.policies.Policy): Action policy.
      sampler (garage.sampler.Sampler): Sampler.
      n_samples (int): Number of policies sampled in one epoch.
      discount (float): Environment reward discount.
      sigma0 (float): Initial std for param distribution.
class_docstr_tok: ["Covariance","Matrix","Adaptation","Evolution","Strategy",".","Note",":","The","CMA-ES","method","can","hardly","learn","a","successful","policy","even","for","simple","task",".","It","is","still","maintained","here","only","for","consistency","with","original","rllab","paper",".","Args",":","env_spec","(","EnvSpec",")",":","Environment","specification",".","policy","(","garage.np.policies.Policy",")",":","Action","policy",".","sampler","(","garage.sampler.Sampler",")",":","Sampler",".","n_samples","(","int",")",":","Number","of","policies","sampled","in","one","epoch",".","discount","(","float",")",":","Environment","reward","discount",".","sigma0","(","float",")",":","Initial","std","for","param","distribution","."]
docstr: Return sample parameters.
  
  Returns:
      np.ndarray: A numpy array of parameter values.
docstr_tok: ["Return","sample","parameters",".","Returns",":","np.ndarray",":","A","numpy","array","of","parameter","values","."]
code: def _sample_params(self):
      """Return sample parameters.
  
      Returns:
          np.ndarray: A numpy array of parameter values.
  
      """
      return self._es.ask()
  
file_path: garage/src/garage/np/algos/cma_es.py
imports: import collections
  import cma
  from dowel import logger, tabular
  import numpy
  from garage import log_performance
  from garage.np.algos.rl_algorithm import RLAlgorithm
label_desc: Use image node_id 2 for calling the CMAES obj's underlying member method code with example usage: obj._sample_params() and returns: self