class_docstr: Computes dual exponential decay [1].
  y = a1 + a2 Exp[-t / a4] + a3 Exp[-t/a5]
      
docstr: generates a dual decay model instance from a list of coefficients
code: def ForwardFactory(self, coeffs):
      """generates a dual decay model instance from a list of coefficients"""
      a1, a2, a3, a4, a5 = coeffs
  
      def forward_decay(evalpts):
          """a dual exponential decay over a 1D numpy array
  with (a1,a2,a3,a4,a5) = (%s,%s,%s,%s,%s)""" % (
              a1,
              a2,
              a3,
              a4,
              a5,
          )
          return self.evaluate((a1, a2, a3, a4, a5), evalpts)
  
      return forward_decay
  
file_path: mystic/mystic/models/br8.py
imports: from .abstract_model import AbstractModel
  from numpy import array, asarray
  from numpy import sum
  from numpy import exp, sqrt
  from mystic.forward_model import CostFactory
label_desc: Use image node_id 3 for calling the BevingtonDecay obj's underlying member method code with example usage: obj.ForwardFactory(coeffs) and returns: forward_decay, self