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from pygslodeiv2 import integrate_predefined, fpes
import numpy as np
from van_der_pol import get_f_and_j


    

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help(integrate_predefined)


    

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rhs, jac = get_f_and_j(1.0)
xout = np.linspace(0, 10, 200)
yout, info = integrate_predefined(
    rhs, jac, [0, 1], xout, dx0=1e-12, atol=1e-15, rtol=1e-15,
    record_rhs_xvals=True, record_jac_xvals=True, record_order=True,
    record_fpe=True, nsteps=2000)
print(info['nfev'], info['success'], info['time_wall'])


    

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import matplotlib.pyplot as plt
%matplotlib inline
fig, axes = plt.subplots(5, 1, figsize=(16,16))
for k, ax in zip(['steps', 'rhs', 'jac'], axes.flat):
    ax.vlines(xout if k == 'steps' else info[k + '_xvals'], 0, 1, transform=ax.get_xaxis_transform(),
              colors='darkgreen', alpha=0.006 if k == 'rhs' else 0.5)
    #for x in xout if k == 'steps' else info[k + '_xvals']:
    #    ax.axvline(x, c='darkgreen', alpha=0.1)
    ax.plot(xout, yout)
    ax.set_xlim([xout[0], xout[-1]])
    ax.set_ylabel(k)
axes[-2].plot(xout[1:], info['fpes'][1:] - fpes['FE_INEXACT'])
axes[-2].set_ylabel('fpes')
axes[-1].plot(xout, info['orders'])
axes[-1].set_ylabel('order')
_ = plt.tight_layout


    

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info.keys()


    

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fpes