def forward(self, x, mask):
"""
x, q(query), k(key), v(value) : (B(batch_size), S(seq_len), D(dim))
mask : (B(batch_size) x S(seq_len))
* split D(dim) into (H(n_heads), W(width of head)) ; D = H * W
"""
# (B, S, D) -proj-> (B, S, D) -split-> (B, S, H, W) -trans-> (B, H, S, W)
q, k, v = self.proj_q(x), self.proj_k(x), self.proj_v(x)
#q, k, v = torch.squeeze(self.proj_q(torch.unsqueeze(x, dim=1)), dim=1), \
# torch.squeeze(self.proj_k(torch.unsqueeze(x, dim=1)), dim=1), \
# self.proj_v(x)
q, k, v = (split_last(x, (self.n_heads, -1)).transpose(1, 2)
for x in [q, k, v])
# (B, H, S, W) @ (B, H, W, S) -> (B, H, S, S) -softmax-> (B, H, S, S)
scores = q @ k.transpose(-2, -1) / np.sqrt(k.size(-1))
if mask is not None:
mask = mask[:, None, None, :].float()
scores -= 10000.0 * (1.0 - mask)
scores = self.drop(F.softmax(scores, dim=-1))
# (B, H, S, S) @ (B, H, S, W) -> (B, H, S, W) -trans-> (B, S, H, W)
h = (scores @ v).transpose(1, 2).contiguous()
# -merge-> (B, S, D)
h = merge_last(h, 2)
self.scores = scores
return h
def forward(self, x, mask):
"""
:param x, q, k, v: (Batch_size, Seq_len, Dim)
:param mask: (Batch_size, Seq_len)
* split Dim into (H(n_heads), W(width of head)) ; Dim = H * W
:return: (Batch, seq_len, Dim)
"""
# (B, S, D) -proj-> (B, S, D) -split-> (B, S, H, W) -trans-> (B, H, S, W)
q, k, v = self.proj_q(x), self.proj_k(x), self.proj_v(x)
# n_head 수만큼 쪼개서 사용 q, k, v (batch, n_head, seq_length, head_features)
q, k, v = (split_last(x, (self.n_heads, -1)).transpose(1, 2)
for x in [q, k, v])
# Scale Dot Product Attention 부분(multi head인 경우 고려)
# (B, H, S, W) @ (B, H, W, S) -> (B, H, S, S) -softmax-> (B, H, S, S)
scores = q @ k.transpose(-2, -1) / np.sqrt(k.size(-1))
if mask is not None:
mask = mask[:, None, None, :].float()
scores -= 10000.0 * (1.0 - mask)
scores = self.drop(F.softmax(scores, dim=-1))
# (B, H, S, S) @ (B, H, S, W) -> (B, H, S, W) -trans-> (B, S, H, W)
h = (scores @ v).transpose(1, 2).contiguous()
# -merge-> (B, S, D=H*W)
h = merge_last(h, 2)
self.scores = scores
return h
def forward(self, x):
# mask = None
"""
x, q(query), k(key), v(value) : (B(batch_size), S(seq_len), D(hidden_dim))
mask : (B(batch_size) x S(seq_len))
* split D(hidden_dim) into (H(n_heads), W(width of head)) ; D = H * W
"""
# (B, S, D) -proj-> (B, S, D) -split-> (B, S, H, W) -trans-> (B, H, S, W)
q, k, v = self.proj_q(x), self.proj_k(x), self.proj_v(x)
q, k, v = (split_last(x, (self.n_heads, -1)).transpose(1, 2)
for x in [q, k, v])
# (B, H, S, W) @ (B, H, W, S) -> (B, H, S, S) -softmax-> (B, H, S, S)
scores = q @ k.transpose(-2, -1) / np.sqrt(k.size(-1))
scores = self.drop(F.softmax(scores, dim=-1))
# (B, H, S, S) @ (B, H, S, W) -> (B, H, S, W) -trans-> (B, S, H, W)
h = (scores @ v).transpose(1, 2).contiguous()
# -merge-> (B, S, D)
h = merge_last(h, 2)
self.scores = scores
return h