class_docstr: Dictionary-like object representing an SALib Problem specification.
  
  Attributes
  ----------
  samples : np.array, of generated samples
  results : np.array, of evaluations (i.e., model outputs)
  analysis : np.array or dict, of sensitivity indices
docstr: Plot results as a heatmap.
  
  Parameters
  ----------
  metric : str or None, name of output to analyze (display all if `None`)
  index : str or None, name of index to plot, dependent on what
              analysis was conducted (ST, S1, etc; displays all if `None`)
  title : str, title of plot to use (defaults to the same as `metric`)
  ax : axes object, matplotlib axes object to use for plot.
          Creates a new figure if not provided.
  
  Returns
  -------
  ax : matplotlib axes object
docstr_tok: ["Plot","results","as","a","heatmap",".","Parameters","--","--","--","--","--","metric",":","str","or","None",",","name","of","output","to","analyze","(","display","all","if","`","None","`",")","index",":","str","or","None",",","name","of","index","to","plot",",","dependent","on","what","analysis","was","conducted","(","ST",",","S1",",","etc",";","displays","all","if","`","None","`",")","title",":","str",",","title","of","plot","to","use","(","defaults","to","the","same","as","`","metric","`",")","ax",":","axes","object",",","matplotlib","axes","object","to","use","for","plot",".","Creates","a","new","figure","if","not","provided",".","Returns","--","--","--","-","ax",":","matplotlib","axes","object"]
code: def heatmap(
      self,
      metric: str = None,
      index: str = None,
      title: str = None,
      ax=None,
  ):
      """Plot results as a heatmap.
  
      Parameters
      ----------
      metric : str or None, name of output to analyze (display all if `None`)
      index : str or None, name of index to plot, dependent on what
                  analysis was conducted (ST, S1, etc; displays all if `None`)
      title : str, title of plot to use (defaults to the same as `metric`)
      ax : axes object, matplotlib axes object to use for plot.
              Creates a new figure if not provided.
  
      Returns
      -------
      ax : matplotlib axes object
      """
      from SALib.plotting.heatmap import heatmap  # type: ignore
  
      return heatmap(self, metric, index, title, ax)
  
imports: import warnings
  import importlib
  from types import MethodType
  from functools import partial, wraps
  from multiprocess import Pool, cpu_count
  import numpy
  import SALib.sample
  import SALib.analyze
  from SALib.util import avail_approaches
  from SALib.util.results import ResultDict
label_desc: Use image node_id 17 for calling the ProblemSpec obj's underlying member method code with example usage: obj.heatmap(metric, index, title, ax) and returns: heatmap