class Generator:
def __init__(self, corpus, sig_order, **params):
self.corpus = corpus
self.order = sig_order
# Model parameters
n_latent = params.get("n_latent", 8)
alpha = params.get("alpha", 0.003)
self._build_dataset()
self.generator = CVAE(n_latent=n_latent, alpha=alpha)
def _logsig(self, path):
return tosig.stream2logsig(path, self.order)
def _build_dataset(self):
self.logsigs = np.array([self._logsig(path) for path in tqdm(self.corpus, desc="Computing log-signatures")])
self.scaler = MinMaxScaler(feature_range=(0.00001, 0.99999))
self.logsigs_norm = self.scaler.fit_transform(self.logsigs)
def train(self, n_epochs=10000):
self.generator.train(self.logsigs_norm, data_cond=None, n_epochs=n_epochs)
def generate(self, n_samples=None, normalised=False):
generated = self.generator.generate(cond=None, n_samples=n_samples)
if normalised:
return generated
if n_samples is None:
return self.scaler.inverse_transform(generated.reshape(1, -1))[0]
return self.scaler.inverse_transform(generated)
class MarketGenerator:
def __init__(self,
ticker,
start=datetime.date(2000, 1, 1),
end=datetime.date(2019, 1, 1),
freq="M",
sig_order=4,
rough_bergomi=None):
self.ticker = ticker
self.start = start
self.end = end
self.freq = freq
self.order = sig_order
if rough_bergomi:
self._load_rough_bergomi(rough_bergomi)
else:
self._load_data()
self._build_dataset()
self.generator = CVAE(n_latent=8, alpha=0.003)
def _load_rough_bergomi(self, params):
grid_points_dict = {"M": 28, "W": 5, "Y": 252}
grid_points = grid_points_dict[self.freq]
params["T"] = grid_points / grid_points_dict["Y"]
paths = rough_bergomi(grid_points, **params)
self.windows = [leadlag(path) for path in paths]
def _load_data(self):
try:
self.data = pdr.get_data_yahoo(self.ticker, self.start,
self.end)["Close"]
except:
raise RuntimeError(
f"Could not download data for {self.ticker} from {self.start} to {self.end}."
)
self.windows = []
for _, window in self.data.resample(self.freq):
values = window.values # / window.values[0]
path = leadlag(values)
self.windows.append(path)
def _logsig(self, path):
return tosig.stream2logsig(path, self.order)
def _build_dataset(self):
if self.order:
self.orig_logsig = np.array([
self._logsig(path)
for path in tqdm(self.windows, desc="Computing log-signatures")
])
else:
self.orig_logsig = np.array(
[np.diff(np.log(path[::2, 1])) for path in self.windows])
self.orig_logsig = np.array(
[p for p in self.orig_logsig if len(p) >= 4])
steps = min(map(len, self.orig_logsig))
self.orig_logsig = np.array(
[val[:steps] for val in self.orig_logsig])
self.scaler = MinMaxScaler(feature_range=(0.00001, 0.99999))
logsig = self.scaler.fit_transform(self.orig_logsig)
self.logsigs = logsig[1:]
self.conditions = logsig[:-1]
def train(self, n_epochs=10000):
self.generator.train(self.logsigs, self.conditions, n_epochs=n_epochs)
def generate(self, logsig, n_samples=None, normalised=False):
generated = self.generator.generate(logsig, n_samples=n_samples)
if normalised:
return generated
if n_samples is None:
return self.scaler.inverse_transform(generated.reshape(1, -1))[0]
return self.scaler.inverse_transform(generated)
