class_docstr: Gumbel copula.
  
  Dependence is greater in the positive tail than in the negative.
  
  .. math::
  
      C_\theta(u,v) = \exp\!\left[ -\left( (-\log(u))^\theta +
      (-\log(v))^\theta \right)^{1/\theta} \right]
  
  with :math:`\theta\in[1,\infty)`.
class_docstr_tok: ["Gumbel","copula",".","Dependence","is","greater","in","the","positive","tail","than","in","the","negative",".","..","math",":",":","C_\\theta","(","u",",","v",")","=","\\exp\\","!","\\left","[","-\\left","(","(","-\\log","(","u",")",")","^\\theta","+","(","-\\log","(","v",")",")","^\\theta","\\right",")","^","{","1\/\\theta","}","\\right","]","with",":","math",":","`","\\theta\\in","[","1",",","\\infty",")","`","."]
code: def theta_from_tau(self, tau):
      return 1 / (1 - tau)
  
imports: import sys
  import numpy
  from scipy import stats, integrate, optimize
  from .None import transforms
  from .copulas import Copula
  from statsmodels.tools.rng_qrng import check_random_state
label_desc: Use image node_id 7 for calling the GumbelCopula obj's underlying member method code with example usage: obj.theta_from_tau(tau) and returns: unknown