使用Python编程语言实现copula-DCC-GARCH模型进行金融时间序列分析
时间: 2024-01-07 13:03:20 浏览: 242
好的,下面是一个基本的Python实现copula-DCC-GARCH模型的示例代码,供您参考:
```
import numpy as np
import pandas as pd
import arch
from arch import arch_model
from scipy.stats import norm
from scipy.stats import t
from scipy.optimize import minimize
from copulae import GaussianCopula
# 读取数据
data = pd.read_csv('data.csv')
# 计算收益率
returns = np.log(data['Close']).diff().dropna()
# 初始化GARCH模型
am = arch_model(returns, p=1, q=1, vol='GARCH')
# 拟合GARCH模型
res = am.fit(disp='off')
# 计算预测方差
volatility = res.conditional_volatility
# 计算标准化残差
standardized_residuals = res.resid / volatility
# 计算相关矩阵
corr_matrix = np.corrcoef(standardized_residuals.T)
# 初始化copula
copula = GaussianCopula(corr_matrix)
# 拟合copula-DCC-GARCH模型
def dcc_garch_likelihood(parameters):
omega = parameters[0]
alpha = parameters[1]
beta = parameters[2]
gamma = parameters[3]
df = parameters[4]
copula_corr = copula.fit([norm.cdf(standardized_residuals[:,0]), norm.cdf(standardized_residuals[:,1])])[0][1]
dcc_corr = arch.dcc_garch(omega=omega, alpha=alpha, beta=beta, gamma=gamma, corr0=copula_corr, nobs=len(returns), vol='GARCH', dist='t', df=df, resids=standardized_residuals, options={'maxiter':1000})
dcc_volatility = dcc_corr.conditional_volatility
dcc_loglikelihood = np.sum(t.logpdf(standardized_residuals, df, loc=0, scale=dcc_volatility))
return -dcc_loglikelihood
# 最小化似然函数
initial_params = np.array([0.01, 0.1, 0.85, 0.1, 10.0])
results = minimize(dcc_garch_likelihood, initial_params, method='L-BFGS-B', bounds=((0, None), (0, None), (0, 1), (0, 1), (2.1, None)))
# 输出结果
omega = results.x[0]
alpha = results.x[1]
beta = results.x[2]
gamma = results.x[3]
df = results.x[4]
print('omega: ', omega)
print('alpha: ', alpha)
print('beta: ', beta)
print('gamma: ', gamma)
print('df: ', df)
```
这个代码示例使用了arch包和copulae包。首先,使用arch包计算收益率,并拟合GARCH模型,计算预测方差和标准化残差。然后,计算标准化残差的相关矩阵,并使用copulae包拟合Gaussian copula。最后,定义一个似然函数,使用scipy.optimize包最小化该函数,得到copula-DCC-GARCH模型的参数。
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