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curvefit.core.parameter.Parameter

A parameter for the functional form of the curve

A Parameter is a parameter of the functional form for the curve. For example, if the parametric curve you want to fit has three parameters then you need 3 Parameter objects. A Parameter is made up of one or more Variable objects, which represent the fixed and random effects. Parameters may have link functions that transform the parameter into some other space to enforce, for example, positivity of the parameter (e.g. the parameter representing the scale of a Gaussian distribution can't be negative).

Arguments

  • param_name (str): name of parameter, e.g. 'alpha'
  • link_fun (Callable): the link function for the parameter
  • variables (List[curvefit.core.parameter.Variable]): a list of Variable instances

Attributes

All attributes from the Variables in the list in the variables argument are carried over to Parameter but they are put into a list. For example, the fe_init attribute for Parameter is a list of fe_init attributes for each Variable in the order that they were passed in variables list.

Additional attributes that are not lists of the individual Variable attributes are listed below.

  • self.num_fe (int): total number of effects for the parameter (number of variables)

Usage

from curvefit.core.parameter import Parameter, Variable

var = Variable(covariate='ones', var_link_fun=lambda x: x, fe_init=0., re_init=0.)
param = Parameter(param_name='alpha', link_fun=lambda x: x, variables=[var])