def __get_results(self, x0, y0, x, h):
"""
Return pd.DataFrame object of the results of numerical methods and the analytical solution
:param x0: initial position on x-axis
:param y0: f(x0)
:param x: final position on x-axis
:param h: a grid step
:return: pd.DateFrame object
"""
dic = dict()
x_list, y_list = self.methods.euler_method(Variant.func, x0, y0, h, x)
dic[self.x_column] = x_list
dic[self.columns[0]] = Variant.solution(x_list, x0, y0)
dic[self.columns[1]] = y_list
_, y_list = self.methods.improved_euler_method(Variant.func, x0, y0, h,
x)
dic[self.columns[2]] = y_list
_, y_list = self.methods.runge_kuffa_method(Variant.func, x0, y0, h, x)
dic[self.columns[3]] = y_list
df = pd.DataFrame(dic)
df.fillna(0.0, inplace=True)
return df
