+ # ar_mask is a tensor with 0s and 1s, of same shape as input, with
+ # 1s where tokens should be generated. The others are kept
+ # unchanged.
+
+ def masked_inplace_autoregression(
+ self, input, ar_mask, forbidden_tokens=None, deterministic_synthesis=False
+ ):
+ to_generate = (ar_mask.sum(0) > 0).nonzero()
+ if to_generate.min() > 0:
+ self(
+ BracketedSequence(input, 0, to_generate.min())
+ ) # Needed to initialize the model's cache
+ for s in range(to_generate.min(), to_generate.max() + 1):
+ output = self(BracketedSequence(input, s, 1)).x
+ logits = output[:, s]
+ if forbidden_tokens is not None:
+ logits = logits.masked_fill(forbidden_tokens, float("-inf"))
+ if deterministic_synthesis:
+ t_next = logits.argmax(1)
+ else:
+ dist = torch.distributions.categorical.Categorical(logits=logits)
+ t_next = dist.sample()
+ input[:, s] = ar_mask[:, s] * t_next + (1 - ar_mask[:, s]) * input[:, s]
+