我需要在 tensorflow1 中实现一个 VaR/CVaR 类。我已经在pytorch中实现了它,但是我对tensorflow1不熟悉,我想寻求一些帮助。熟悉 tf1 的人可以帮帮我吗?下面是我在 pytorch 中的 VaR/CVaR 实现。先感谢您。
class CVaR(nn.Module):
def __init__(self, alpha, learning_rate=1e-2):
super(CVaR, self).__init__()
self._alpha = alpha
self._var = nn.Parameter(torch.tensor(1.0), requires_grad=True)
self._optimizer = torch.optim.Adam([{"params": self._var, "lr": learning_rate}])
def forward(self, losses):
return self._var + 1 / self._alpha * torch.relu(losses - self._var)
def zero_grad(self):
"""Reset CVaR internal optimizer."""
self._optimizer.zero_grad()
def step(self):
"""Execute a step of the internal CVaR optimizer."""
self._optimizer.step()
@property
def var(self):
"""Get estimated Value-at-Risk."""
return self._var
class SoftCVaR(CVaR):
def __init__(self, alpha, learning_rate=1e-3, temperature=1):
super(SoftCVaR, self).__init__(alpha, learning_rate=learning_rate)
self._temperature = temperature
def forward(self, losses):
return self._var + self._temperature / self._alpha * torch.log(
1 + torch.exp((losses - self._var) / self._temperature)
)