# -*- coding: utf-8 -*-
"""Examples for Regression Plots

Author: Josef Perktold

"""

import numpy as np
import statsmodels.api as sm
import matplotlib.pyplot as plt

from statsmodels.sandbox.regression.predstd import wls_prediction_std
import statsmodels.graphics.regressionplots as smrp
from statsmodels.graphics.tests.test_regressionplots import TestPlot

#example from tut.ols with changes
#fix a seed for these examples
np.random.seed(9876789)

# OLS non-linear curve but linear in parameters
# ---------------------------------------------

nsample = 100
sig = 0.5
x1 = np.linspace(0, 20, nsample)
x2 = 5 + 3* np.random.randn(nsample)
X = np.c_[x1, x2, np.sin(0.5*x1), (x2-5)**2, np.ones(nsample)]
beta = [0.5, 0.5, 1, -0.04, 5.]
y_true = np.dot(X, beta)
y = y_true + sig * np.random.normal(size=nsample)

#estimate only linear function, misspecified because of non-linear terms
exog0 = sm.add_constant(np.c_[x1, x2], prepend=False)

#    plt.figure()
#    plt.plot(x1, y, 'o', x1, y_true, 'b-')

res = sm.OLS(y, exog0).fit()
#print res.params
#print res.bse


plot_old = 0 #True
if plot_old:

    #current bug predict requires call to model.results
    #print res.model.predict
    prstd, iv_l, iv_u = wls_prediction_std(res)
    plt.plot(x1, res.fittedvalues, 'r-o')
    plt.plot(x1, iv_u, 'r--')
    plt.plot(x1, iv_l, 'r--')
    plt.title('blue: true,   red: OLS')

    plt.figure()
    plt.plot(res.resid, 'o')
    plt.title('Residuals')

    fig2 = plt.figure()
    ax = fig2.add_subplot(2,1,1)
    #namestr = ' for %s' % self.name if self.name else ''
    plt.plot(x1, res.resid, 'o')
    ax.set_title('residuals versus exog')# + namestr)
    ax = fig2.add_subplot(2,1,2)
    plt.plot(x2, res.resid, 'o')

    fig3 = plt.figure()
    ax = fig3.add_subplot(2,1,1)
    #namestr = ' for %s' % self.name if self.name else ''
    plt.plot(x1, res.fittedvalues, 'o')
    ax.set_title('Fitted values versus exog')# + namestr)
    ax = fig3.add_subplot(2,1,2)
    plt.plot(x2, res.fittedvalues, 'o')

    fig4 = plt.figure()
    ax = fig4.add_subplot(2,1,1)
    #namestr = ' for %s' % self.name if self.name else ''
    plt.plot(x1, res.fittedvalues + res.resid, 'o')
    ax.set_title('Fitted values plus residuals versus exog')# + namestr)
    ax = fig4.add_subplot(2,1,2)
    plt.plot(x2, res.fittedvalues + res.resid, 'o')

    # see http://www.itl.nist.gov/div898/software/dataplot/refman1/auxillar/partregr.htm
    fig5 = plt.figure()
    ax = fig5.add_subplot(2,1,1)
    #namestr = ' for %s' % self.name if self.name else ''
    res1a = sm.OLS(y, exog0[:,[0,2]]).fit()
    res1b = sm.OLS(x1, exog0[:,[0,2]]).fit()
    plt.plot(res1b.resid, res1a.resid, 'o')
    res1c = sm.OLS(res1a.resid, res1b.resid).fit()
    plt.plot(res1b.resid, res1c.fittedvalues, '-')
    ax.set_title('Partial Regression plot')# + namestr)
    ax = fig5.add_subplot(2,1,2)
    #plt.plot(x2, res.fittedvalues + res.resid, 'o')
    res2a = sm.OLS(y, exog0[:,[0,1]]).fit()
    res2b = sm.OLS(x2, exog0[:,[0,1]]).fit()
    plt.plot(res2b.resid, res2a.resid, 'o')
    res2c = sm.OLS(res2a.resid, res2b.resid).fit()
    plt.plot(res2b.resid, res2c.fittedvalues, '-')

    # see http://www.itl.nist.gov/div898/software/dataplot/refman1/auxillar/ccpr.htm
    fig6 = plt.figure()
    ax = fig6.add_subplot(2,1,1)
    #namestr = ' for %s' % self.name if self.name else ''
    x1beta = x1*res.params[1]
    x2beta = x2*res.params[2]
    plt.plot(x1, x1beta + res.resid, 'o')
    plt.plot(x1, x1beta, '-')
    ax.set_title('X_i beta_i plus residuals versus exog (CCPR)')# + namestr)
    ax = fig6.add_subplot(2,1,2)
    plt.plot(x2, x2beta + res.resid, 'o')
    plt.plot(x2, x2beta, '-')


    #print res.summary()

doplots = 1
if doplots:
    fig1 = smrp.plot_fit(res, 0, y_true=None)
    smrp.plot_fit(res, 1, y_true=None)
    smrp.plot_partregress_grid(res, exog_idx=[0,1])
    smrp.plot_regress_exog(res, exog_idx=0)
    smrp.plot_ccpr(res, exog_idx=0)
    smrp.plot_ccpr_grid(res, exog_idx=[0,1])

tp = TestPlot()
tp.test_plot_fit()

fig1 = smrp.plot_partregress_grid(res, exog_idx=[0,1])
#add lowess
ax = fig1.axes[0]
y0 = ax.get_lines()[0]._y
x0 = ax.get_lines()[0]._x
lres = sm.nonparametric.lowess(y0, x0, frac=0.2)
ax.plot(lres[:,0], lres[:,1], 'r', lw=1.5)
ax = fig1.axes[1]
y0 = ax.get_lines()[0]._y
x0 = ax.get_lines()[0]._x
lres = sm.nonparametric.lowess(y0, x0, frac=0.2)
ax.plot(lres[:,0], lres[:,1], 'r', lw=1.5)

#plt.show()
