class_docstr: A trace implementation of ELBO-based SVI that supports
  - exhaustive enumeration over discrete sample sites, and
  - local parallel sampling over any sample site in the guide.
  
  To enumerate over a sample site in the ``guide``, mark the site with either
  ``infer={'enumerate': 'sequential'}`` or
  ``infer={'enumerate': 'parallel'}``. To configure all guide sites at once,
  use :func:`~pyro.infer.enum.config_enumerate`. To enumerate over a sample
  site in the ``model``, mark the site ``infer={'enumerate': 'parallel'}``
  and ensure the site does not appear in the ``guide``.
  
  This assumes restricted dependency structure on the model and guide:
  variables outside of an :class:`~pyro.plate` can never depend on
  variables inside that :class:`~pyro.plate`.
class_docstr_tok: ["A","trace","implementation","of","ELBO-based","SVI","that","supports","-","exhaustive","enumeration","over","discrete","sample","sites",",","and","-","local","parallel","sampling","over","any","sample","site","in","the","guide",".","To","enumerate","over","a","sample","site","in","the","``","guide","``",",","mark","the","site","with","either","``","infer=","{","'enumerate","'",":","'sequential","'","}","``","or","``","infer=","{","'enumerate","'",":","'parallel","'","}","``",".","To","configure","all","guide","sites","at","once",",","use",":","func",":","`","~pyro.infer.enum.config_enumerate","`",".","To","enumerate","over","a","sample","site","in","the","``","model","``",",","mark","the","site","``","infer=","{","'enumerate","'",":","'parallel","'","}","``","and","ensure","the","site","does","not","appear","in","the","``","guide","``",".","This","assumes","restricted","dependency","structure","on","the","model","and","guide",":","variables","outside","of","an",":","class",":","`","~pyro.plate","`","can","never","depend","on","variables","inside","that",":","class",":","`","~pyro.plate","`","."]
docstr: :returns: an estimate of the ELBO
  :rtype: float
  
  Estimates the ELBO using ``num_particles`` many samples (particles).
docstr_tok: [":","returns",":","an","estimate","of","the","ELBO",":","rtype",":","float","Estimates","the","ELBO","using","``","num_particles","``","many","samples","(","particles",")","."]
code: def loss(self, model, guide, *args, **kwargs):
      """
      :returns: an estimate of the ELBO
      :rtype: float
  
      Estimates the ELBO using ``num_particles`` many samples (particles).
      """
      elbo = 0.0
      for model_trace, guide_trace in self._get_traces(
          model, guide, args, kwargs
      ):
          elbo_particle = _compute_dice_elbo(model_trace, guide_trace)
          if is_identically_zero(elbo_particle):
              continue
  
          elbo += elbo_particle.item() / self.num_particles
  
      loss = -elbo
      warn_if_nan(loss, "loss")
      return loss
  
imports: import queue
  import warnings
  import weakref
  from collections import OrderedDict
  import torch
  from opt_einsum import shared_intermediates
  import pyro
  import pyro.distributions
  import pyro.ops.jit
  import pyro.poutine
  from pyro.distributions.util import is_identically_zero
  from pyro.infer.elbo import ELBO
  from pyro.infer.enum import get_importance_trace, iter_discrete_escape, iter_discrete_extend
  from pyro.infer.util import Dice, is_validation_enabled
  from pyro.ops import packed
  from pyro.ops.contract import contract_tensor_tree, contract_to_tensor
  from pyro.ops.rings import SampleRing
  from pyro.poutine.enum_messenger import EnumMessenger
  from pyro.util import check_traceenum_requirements, ignore_jit_warnings, warn_if_nan
label_desc: Use image node_id 3 for calling the TraceEnum_ELBO obj's underlying member method code with example usage: obj.loss(model, guide) and returns: loss