#  ___________________________________________________________________________
#
#  Pyomo: Python Optimization Modeling Objects
#  Copyright (c) 2008-2022
#  National Technology and Engineering Solutions of Sandia, LLC
#  Under the terms of Contract DE-NA0003525 with National Technology and
#  Engineering Solutions of Sandia, LLC, the U.S. Government retains certain
#  rights in this software.
#  This software is distributed under the 3-clause BSD License.
#  ___________________________________________________________________________

import numpy as np
import pandas as pd
from itertools import product
import pyomo.contrib.parmest.parmest as parmest
from pyomo.contrib.parmest.examples.rooney_biegler.rooney_biegler import rooney_biegler_model


def main():
    # Vars to estimate
    theta_names = ['asymptote', 'rate_constant']
    
    # Data
    data = pd.DataFrame(data=[[1,8.3],[2,10.3],[3,19.0],
                              [4,16.0],[5,15.6],[7,19.8]],
                        columns=['hour', 'y'])
    
    # Sum of squared error function
    def SSE(model, data):  
        expr = sum((data.y[i] - model.response_function[data.hour[i]])**2 for i in data.index)
        return expr
    
    # Create an instance of the parmest estimator
    pest = parmest.Estimator(rooney_biegler_model, data, theta_names, SSE)
    
    # Parameter estimation
    obj, theta = pest.theta_est()
    
    # Find the objective value at each theta estimate
    asym = np.arange(10, 30, 2)
    rate = np.arange(0, 1.5, 0.1)
    theta_vals = pd.DataFrame(list(product(asym, rate)), columns=['asymptote', 'rate_constant'])
    obj_at_theta = pest.objective_at_theta(theta_vals)
    
    # Run the likelihood ratio test
    LR = pest.likelihood_ratio_test(obj_at_theta, obj, [0.8, 0.85, 0.9, 0.95])
    
    # Plot results
    parmest.graphics.pairwise_plot(LR, theta, 0.8, 
                          title='LR results within 80% confidence region')

if __name__ == "__main__":
    main()
    
    