diff --git a/jclip/mha.py b/jclip/mha.py new file mode 100644 index 0000000..13eeedf --- /dev/null +++ b/jclip/mha.py @@ -0,0 +1,650 @@ +from typing import Optional, Tuple, List +import warnings +import math + +import jittor as jt +from jittor import Var +from jittor.nn import Module, Linear, softmax, pad, linear, dropout +from jittor.init import xavier_uniform_, xavier_gauss_, constant_ + + +def _canonical_mask( + mask: Optional[Var], + mask_name: str, + other_type, + other_name: str, + target_type, + check_other: bool = True, +) -> Optional[Var]: + + if mask is not None: + _mask_dtype = mask.dtype + _mask_is_float = mask.dtype == jt.float16 or mask.dtype == jt.float32 or mask.dtype == jt.float64 + if _mask_dtype != jt.bool and not _mask_is_float: + raise AssertionError( + f"only bool and floating types of {mask_name} are supported") + if check_other and other_type is not None: + if _mask_dtype != other_type: + warnings.warn( + f"Support for mismatched {mask_name} and {other_name} " + "is deprecated. Use same type for both instead.") + if not _mask_is_float: + # WARNING(514flowey): Check Here + new_mask = jt.zeros_like(mask, dtype=target_type) + new_mask[mask] = float("-inf") + mask = new_mask + return mask + + +def _none_or_dtype(input: Optional[Var]): + if input is None: + return None + elif isinstance(input, jt.Var): + return input.dtype + + +def baddbmm(input_var: jt.Var, + batch1: jt.Var, + batch2: jt.Var, + beta=1, + alpha=1) -> jt.Var: + # WARNING(514flowey): Check here + return beta * input_var + alpha * (batch1 @ batch2) + + +def scaled_dot_product_attention(query, + key, + value, + attn_mask=None, + dropout_p=0.0, + is_causal=False, + scale=None, + training=True) -> jt.Var: + # Efficient implementation equivalent to the following: + L, S = query.size(-2), key.size(-2) + scale_factor = 1 / math.sqrt(query.size(-1)) if scale is None else scale + attn_bias = jt.zeros(L, S, dtype=query.dtype) + if is_causal: + assert attn_mask is None + temp_mask = jt.ones(L, S, dtype=jt.bool).tril(diagonal=0) + attn_bias[jt.logical_not(temp_mask)] = float("-inf") + # attn_bias.to(query.dtype) + attn_bias = jt.array(attn_bias, query.dtype) + + if attn_mask is not None: + if attn_mask.dtype == jt.bool: + attn_bias[jt.logical_not(temp_mask)] = float("-inf") + else: + attn_bias += attn_mask + attn_weight = query @ key.transpose(-2, -1) * scale_factor + attn_weight += attn_bias + attn_weight = softmax(attn_weight, dim=-1) + attn_weight = dropout(attn_weight, dropout_p, is_train=training) + return attn_weight @ value + + +def _mha_shape_check(query: Var, key: Var, value: Var, + key_padding_mask: Optional[Var], attn_mask: Optional[Var], + num_heads: int): + if query.dim() == 3: + is_batched = True + assert key.dim() == 3 and value.dim() == 3, \ + ("For batched (3-D) `query`, expected `key` and `value` to be 3-D" + f" but found {key.dim()}-D and {value.dim()}-D Vars respectively") + if key_padding_mask is not None: + assert key_padding_mask.dim() == 2, \ + ("For batched (3-D) `query`, expected `key_padding_mask` to be `None` or 2-D" + f" but found {key_padding_mask.dim()}-D Var instead") + if attn_mask is not None: + assert attn_mask.dim() in (2, 3), \ + ("For batched (3-D) `query`, expected `attn_mask` to be `None`, 2-D or 3-D" + f" but found {attn_mask.dim()}-D Var instead") + elif query.dim() == 2: + is_batched = False + assert key.dim() == 2 and value.dim() == 2, \ + ("For unbatched (2-D) `query`, expected `key` and `value` to be 2-D" + f" but found {key.dim()}-D and {value.dim()}-D Vars respectively") + + if key_padding_mask is not None: + assert key_padding_mask.dim() == 1, \ + ("For unbatched (2-D) `query`, expected `key_padding_mask` to be `None` or 1-D" + f" but found {key_padding_mask.dim()}-D Var instead") + + if attn_mask is not None: + assert attn_mask.dim() in (2, 3), \ + ("For unbatched (2-D) `query`, expected `attn_mask` to be `None`, 2-D or 3-D" + f" but found {attn_mask.dim()}-D Var instead") + if attn_mask.dim() == 3: + expected_shape = (num_heads, query.shape[0], key.shape[0]) + assert attn_mask.shape == expected_shape, \ + (f"Expected `attn_mask` shape to be {expected_shape} but got {attn_mask.shape}") + else: + raise AssertionError( + f"query should be unbatched 2D or batched 3D Var but received {query.dim()}-D query Var" + ) + + return is_batched + + +def _in_projection_packed( + q: Var, + k: Var, + v: Var, + w: Var, + b: Optional[Var] = None, +) -> List[Var]: + E = q.size(-1) + if k is v: + if q is k: + # self-attention + proj = linear(q, w, b) + # reshape to 3, E and not E, 3 is deliberate for better memory coalescing and keeping same order as chunk() + # proj = proj.unflatten(-1, (3, E)).unsqueeze(0).transpose(0, -2).squeeze(-2).contiguous() + nshape = proj.shape[:-1] + (3, E) + proj = proj.reshape(nshape).unsqueeze(0).transpose(0, + -2).squeeze(-2) + return proj[0], proj[1], proj[2] + else: + # encoder-decoder attention + w_q, w_kv = w.split([E, E * 2]) + if b is None: + b_q = b_kv = None + else: + b_q, b_kv = b.split([E, E * 2]) + q_proj = linear(q, w_q, b_q) + kv_proj = linear(k, w_kv, b_kv) + # reshape to 2, E and not E, 2 is deliberate for better memory coalescing and keeping same order as chunk() + # kv_proj = kv_proj.unflatten(-1, (2, E)).unsqueeze(0).transpose(0, -2).squeeze(-2).contiguous() + nshape = kv_proj.shape[:-1] + (2, E) + kv_proj = kv_proj.reshape(nshape).unsqueeze(0).transpose( + 0, -2).squeeze(-2) + return (q_proj, kv_proj[0], kv_proj[1]) + else: + w_q, w_k, w_v = w.chunk(3) + if b is None: + b_q = b_k = b_v = None + else: + b_q, b_k, b_v = b.chunk(3) + return linear(q, w_q, b_q), linear(k, w_k, b_k), linear(v, w_v, b_v) + + +def _in_projection( + q: Var, + k: Var, + v: Var, + w_q: Var, + w_k: Var, + w_v: Var, + b_q: Optional[Var] = None, + b_k: Optional[Var] = None, + b_v: Optional[Var] = None, +) -> Tuple[Var, Var, Var]: + Eq, Ek, Ev = q.size(-1), k.size(-1), v.size(-1) + assert w_q.shape == ( + Eq, Eq + ), f"expecting query weights shape of {(Eq, Eq)}, but got {w_q.shape}" + assert w_k.shape == ( + Eq, + Ek), f"expecting key weights shape of {(Eq, Ek)}, but got {w_k.shape}" + assert w_v.shape == ( + Eq, Ev + ), f"expecting value weights shape of {(Eq, Ev)}, but got {w_v.shape}" + assert b_q is None or b_q.shape == ( + Eq, ), f"expecting query bias shape of {(Eq,)}, but got {b_q.shape}" + assert b_k is None or b_k.shape == ( + Eq, ), f"expecting key bias shape of {(Eq,)}, but got {b_k.shape}" + assert b_v is None or b_v.shape == ( + Eq, ), f"expecting value bias shape of {(Eq,)}, but got {b_v.shape}" + return linear(q, w_q, b_q), linear(k, w_k, b_k), linear(v, w_v, b_v) + + +def multi_head_attention_forward( + query: Var, + key: Var, + value: Var, + embed_dim_to_check: int, + num_heads: int, + in_proj_weight: Optional[Var], + in_proj_bias: Optional[Var], + bias_k: Optional[Var], + bias_v: Optional[Var], + add_zero_attn: bool, + dropout_p: float, + out_proj_weight: Var, + out_proj_bias: Optional[Var], + training: bool = True, + key_padding_mask: Optional[Var] = None, + need_weights: bool = True, + attn_mask: Optional[Var] = None, + use_separate_proj_weight: bool = False, + q_proj_weight: Optional[Var] = None, + k_proj_weight: Optional[Var] = None, + v_proj_weight: Optional[Var] = None, + static_k: Optional[Var] = None, + static_v: Optional[Var] = None, + average_attn_weights: bool = True, + is_causal: bool = False, +) -> Tuple[Var, Optional[Var]]: + + is_batched = _mha_shape_check(query, key, value, key_padding_mask, + attn_mask, num_heads) + + # For unbatched input, we unsqueeze at the expected batch-dim to pretend that the input + # is batched, run the computation and before returning squeeze the + # batch dimension so that the output doesn't carry this temporary batch dimension. + if not is_batched: + # unsqueeze if the input is unbatched + query = query.unsqueeze(1) + key = key.unsqueeze(1) + value = value.unsqueeze(1) + if key_padding_mask is not None: + key_padding_mask = key_padding_mask.unsqueeze(0) + + # set up shape vars + tgt_len, bsz, embed_dim = query.shape + src_len, _, _ = key.shape + + key_padding_mask = _canonical_mask(mask=key_padding_mask, + mask_name="key_padding_mask", + other_type=_none_or_dtype(attn_mask), + other_name="attn_mask", + target_type=query.dtype) + + if is_causal and attn_mask is None: + raise RuntimeError( + "Need attn_mask if specifying the is_causal hint. " + "You may use the Transformer module method " + "`generate_square_subsequent_mask` to create this mask.") + + if is_causal and key_padding_mask is None and not need_weights: + # when we have a kpm or need weights, we need attn_mask + # Otherwise, we use the is_causal hint go as is_causal + # indicator to SDPA. + attn_mask = None + else: + attn_mask = _canonical_mask( + mask=attn_mask, + mask_name="attn_mask", + other_type=None, + other_name="", + target_type=query.dtype, + check_other=False, + ) + + if key_padding_mask is not None: + # We have the attn_mask, and use that to merge kpm into it. + # Turn off use of is_causal hint, as the merged mask is no + # longer causal. + is_causal = False + + assert embed_dim == embed_dim_to_check, \ + f"was expecting embedding dimension of {embed_dim_to_check}, but got {embed_dim}" + if isinstance(embed_dim, jt.Var): + # embed_dim can be a Var when JIT tracing + head_dim = embed_dim.div(num_heads, rounding_mode='trunc') + else: + head_dim = embed_dim // num_heads + assert head_dim * num_heads == embed_dim, f"embed_dim {embed_dim} not divisible by num_heads {num_heads}" + if use_separate_proj_weight: + # allow MHA to have different embedding dimensions when separate projection weights are used + assert key.shape[:2] == value.shape[:2], \ + f"key's sequence and batch dims {key.shape[:2]} do not match value's {value.shape[:2]}" + else: + assert key.shape == value.shape, f"key shape {key.shape} does not match value shape {value.shape}" + + # + # compute in-projection + # + if not use_separate_proj_weight: + assert in_proj_weight is not None, "use_separate_proj_weight is False but in_proj_weight is None" + q, k, v = _in_projection_packed(query, key, value, in_proj_weight, + in_proj_bias) + else: + assert q_proj_weight is not None, "use_separate_proj_weight is True but q_proj_weight is None" + assert k_proj_weight is not None, "use_separate_proj_weight is True but k_proj_weight is None" + assert v_proj_weight is not None, "use_separate_proj_weight is True but v_proj_weight is None" + if in_proj_bias is None: + b_q = b_k = b_v = None + else: + b_q, b_k, b_v = in_proj_bias.chunk(3) + q, k, v = _in_projection(query, key, value, q_proj_weight, + k_proj_weight, v_proj_weight, b_q, b_k, b_v) + + # prep attention mask + + if attn_mask is not None: + # ensure attn_mask's dim is 3 + if attn_mask.dim() == 2: + correct_2d_size = (tgt_len, src_len) + if attn_mask.shape != correct_2d_size: + raise RuntimeError( + f"The shape of the 2D attn_mask is {attn_mask.shape}, but should be {correct_2d_size}." + ) + attn_mask = attn_mask.unsqueeze(0) + elif attn_mask.dim() == 3: + correct_3d_size = (bsz * num_heads, tgt_len, src_len) + if attn_mask.shape != correct_3d_size: + raise RuntimeError( + f"The shape of the 3D attn_mask is {attn_mask.shape}, but should be {correct_3d_size}." + ) + else: + raise RuntimeError( + f"attn_mask's dimension {attn_mask.dim()} is not supported") + + # add bias along batch dimension (currently second) + if bias_k is not None and bias_v is not None: + assert static_k is None, "bias cannot be added to static key." + assert static_v is None, "bias cannot be added to static value." + k = jt.concat([k, bias_k.repeat(1, bsz, 1)]) + v = jt.concat([v, bias_v.repeat(1, bsz, 1)]) + if attn_mask is not None: + attn_mask = pad(attn_mask, (0, 1)) + if key_padding_mask is not None: + key_padding_mask = pad(key_padding_mask, (0, 1)) + else: + assert bias_k is None + assert bias_v is None + + # + # reshape q, k, v for multihead attention and make em batch first + # + q = q.view(tgt_len, bsz * num_heads, head_dim).transpose(0, 1) + if static_k is None: + k = k.view(k.shape[0], bsz * num_heads, head_dim).transpose(0, 1) + else: + # TODO finish disentangling control flow so we don't do in-projections when statics are passed + assert static_k.size(0) == bsz * num_heads, \ + f"expecting static_k.size(0) of {bsz * num_heads}, but got {static_k.size(0)}" + assert static_k.size(2) == head_dim, \ + f"expecting static_k.size(2) of {head_dim}, but got {static_k.size(2)}" + k = static_k + if static_v is None: + v = v.view(v.shape[0], bsz * num_heads, head_dim).transpose(0, 1) + else: + # TODO finish disentangling control flow so we don't do in-projections when statics are passed + assert static_v.size(0) == bsz * num_heads, \ + f"expecting static_v.size(0) of {bsz * num_heads}, but got {static_v.size(0)}" + assert static_v.size(2) == head_dim, \ + f"expecting static_v.size(2) of {head_dim}, but got {static_v.size(2)}" + v = static_v + + # add zero attention along batch dimension (now first) + if add_zero_attn: + zero_attn_shape = (bsz * num_heads, 1, head_dim) + k = jt.concat([k, jt.zeros(zero_attn_shape, dtype=k.dtype)], dim=1) + v = jt.concat([v, jt.zeros(zero_attn_shape, dtype=v.dtype)], dim=1) + if attn_mask is not None: + attn_mask = pad(attn_mask, (0, 1)) + if key_padding_mask is not None: + key_padding_mask = pad(key_padding_mask, (0, 1)) + + # update source sequence length after adjustments + src_len = k.size(1) + + # merge key padding and attention masks + if key_padding_mask is not None: + assert key_padding_mask.shape == (bsz, src_len), \ + f"expecting key_padding_mask shape of {(bsz, src_len)}, but got {key_padding_mask.shape}" + key_padding_mask = key_padding_mask.view(bsz, 1, 1, src_len). \ + expand(-1, num_heads, -1, -1).reshape(bsz * num_heads, 1, src_len) + if attn_mask is None: + attn_mask = key_padding_mask + else: + attn_mask = attn_mask + key_padding_mask + + # adjust dropout probability + if not training: + dropout_p = 0.0 + + # + # (deep breath) calculate attention and out projection + # + + if need_weights: + B, Nt, E = q.shape + q_scaled = q / math.sqrt(E) + + assert not (is_causal and attn_mask is None + ), "FIXME: is_causal not implemented for need_weights" + + if attn_mask is not None: + attn_output_weights = baddbmm(attn_mask, q_scaled, + k.transpose(-2, -1)) + else: + attn_output_weights = jt.bmm(q_scaled, k.transpose(-2, -1)) + attn_output_weights = softmax(attn_output_weights, dim=-1) + if dropout_p > 0.0: + attn_output_weights = dropout(attn_output_weights, p=dropout_p) + + attn_output = jt.bmm(attn_output_weights, v) + + attn_output = attn_output.transpose(0, 1).contiguous().view( + tgt_len * bsz, embed_dim) + attn_output = linear(attn_output, out_proj_weight, out_proj_bias) + attn_output = attn_output.view(tgt_len, bsz, attn_output.size(1)) + + # optionally average attention weights over heads + attn_output_weights = attn_output_weights.view(bsz, num_heads, tgt_len, + src_len) + if average_attn_weights: + attn_output_weights = attn_output_weights.mean(dim=1) + + if not is_batched: + # squeeze the output if input was unbatched + attn_output = attn_output.squeeze(1) + attn_output_weights = attn_output_weights.squeeze(0) + return attn_output, attn_output_weights + else: + # attn_mask can be either (L,S) or (N*num_heads, L, S) + # if attn_mask's shape is (1, L, S) we need to unsqueeze to (1, 1, L, S) + # in order to match the input for SDPA of (N, num_heads, L, S) + if attn_mask is not None: + if attn_mask.size(0) == 1 and attn_mask.dim() == 3: + attn_mask = attn_mask.unsqueeze(0) + else: + attn_mask = attn_mask.view(bsz, num_heads, -1, src_len) + + q = q.view(bsz, num_heads, tgt_len, head_dim) + k = k.view(bsz, num_heads, src_len, head_dim) + v = v.view(bsz, num_heads, src_len, head_dim) + + attn_output = scaled_dot_product_attention(q, + k, + v, + attn_mask, + dropout_p, + is_causal, + training=training) + attn_output = attn_output.permute(2, 0, 1, 3).contiguous().view( + bsz * tgt_len, embed_dim) + + attn_output = linear(attn_output, out_proj_weight, out_proj_bias) + attn_output = attn_output.view(tgt_len, bsz, attn_output.size(1)) + if not is_batched: + # squeeze the output if input was unbatched + attn_output = attn_output.squeeze(1) + return attn_output, None + + +class MultiheadAttention(Module): + __constants__ = ['batch_first'] + bias_k: Optional[jt.Var] + bias_v: Optional[jt.Var] + + def __init__(self, + embed_dim, + num_heads, + dropout=0., + bias=True, + add_bias_kv=False, + add_zero_attn=False, + kdim=None, + vdim=None, + batch_first=False, + dtype=jt.float32) -> None: + if embed_dim <= 0 or num_heads <= 0: + raise ValueError( + f"embed_dim and num_heads must be greater than 0," + f" got embed_dim={embed_dim} and num_heads={num_heads} instead" + ) + factory_kwargs = {'dtype': dtype} + super().__init__() + self.embed_dim = embed_dim + self.kdim = kdim if kdim is not None else embed_dim + self.vdim = vdim if vdim is not None else embed_dim + self._qkv_same_embed_dim = self.kdim == embed_dim and self.vdim == embed_dim + + self.num_heads = num_heads + self.dropout = dropout + self.batch_first = batch_first + self.head_dim = embed_dim // num_heads + assert self.head_dim * num_heads == self.embed_dim, "embed_dim must be divisible by num_heads" + + if not self._qkv_same_embed_dim: + self.q_proj_weight = jt.empty((embed_dim, embed_dim), + **factory_kwargs) + self.k_proj_weight = jt.empty((embed_dim, self.kdim), + **factory_kwargs) + self.v_proj_weight = jt.empty((embed_dim, self.vdim), + **factory_kwargs) + self.in_proj_weight = None + else: + self.q_proj_weight = None + self.k_proj_weight = None + self.v_proj_weight = None + self.in_proj_weight = jt.empty((3 * embed_dim, embed_dim), + **factory_kwargs) + + if bias: + self.in_proj_bias = jt.empty(3 * embed_dim, **factory_kwargs) + else: + self.in_proj_bias = None + self.out_proj = Linear(embed_dim, embed_dim, bias=bias) + + if add_bias_kv: + self.bias_k = jt.empty((1, 1, embed_dim), **factory_kwargs) + self.bias_v = jt.empty((1, 1, embed_dim), **factory_kwargs) + else: + self.bias_k = self.bias_v = None + + self.add_zero_attn = add_zero_attn + + self._reset_parameters() + + def _reset_parameters(self): + if self._qkv_same_embed_dim: + xavier_uniform_(self.in_proj_weight) + else: + xavier_uniform_(self.q_proj_weight) + xavier_uniform_(self.k_proj_weight) + xavier_uniform_(self.v_proj_weight) + + if self.in_proj_bias is not None: + constant_(self.in_proj_bias, 0.) + constant_(self.out_proj.bias, 0.) + if self.bias_k is not None: + xavier_gauss_(self.bias_k) + if self.bias_v is not None: + xavier_gauss_(self.bias_v) + + def __setstate__(self, state): + # Support loading old MultiheadAttention checkpoints generated by v1.1.0 + if '_qkv_same_embed_dim' not in state: + state['_qkv_same_embed_dim'] = True + + super().__setstate__(state) + + def execute(self, + query: Var, + key: Var, + value: Var, + key_padding_mask: Optional[Var] = None, + need_weights: bool = True, + attn_mask: Optional[Var] = None, + average_attn_weights: bool = True, + is_causal: bool = False) -> Tuple[Var, Optional[Var]]: + + ##### + # Fast Path is not Supported. + ##### + + is_batched = query.dim() == 3 + + key_padding_mask = _canonical_mask( + mask=key_padding_mask, + mask_name="key_padding_mask", + other_type=_none_or_dtype(attn_mask), + other_name="attn_mask", + target_type=query.dtype) + + attn_mask = _canonical_mask( + mask=attn_mask, + mask_name="attn_mask", + other_type=None, + other_name="", + target_type=query.dtype, + check_other=False, + ) + + if self.batch_first and is_batched: + # make sure that the transpose op does not affect the "is" property + if key is value: + if query is key: + query = key = value = query.transpose(1, 0) + else: + query, key = (x.transpose(1, 0) for x in (query, key)) + value = key + else: + query, key, value = (x.transpose(1, 0) + for x in (query, key, value)) + + if not self._qkv_same_embed_dim: + attn_output, attn_output_weights = multi_head_attention_forward( + query, + key, + value, + self.embed_dim, + self.num_heads, + self.in_proj_weight, + self.in_proj_bias, + self.bias_k, + self.bias_v, + self.add_zero_attn, + self.dropout, + self.out_proj.weight, + self.out_proj.bias, + training=self.is_training(), + key_padding_mask=key_padding_mask, + need_weights=need_weights, + attn_mask=attn_mask, + use_separate_proj_weight=True, + q_proj_weight=self.q_proj_weight, + k_proj_weight=self.k_proj_weight, + v_proj_weight=self.v_proj_weight, + average_attn_weights=average_attn_weights, + is_causal=is_causal) + else: + attn_output, attn_output_weights = multi_head_attention_forward( + query, + key, + value, + self.embed_dim, + self.num_heads, + self.in_proj_weight, + self.in_proj_bias, + self.bias_k, + self.bias_v, + self.add_zero_attn, + self.dropout, + self.out_proj.weight, + self.out_proj.bias, + training=self.is_training(), + key_padding_mask=key_padding_mask, + need_weights=need_weights, + attn_mask=attn_mask, + average_attn_weights=average_attn_weights, + is_causal=is_causal) + if self.batch_first and is_batched: + return attn_output.transpose(1, 0), attn_output_weights + else: + return attn_output, attn_output_weights