78 transformer blocks › 75 MoE blocks › Sparse latent attention › Query heads
Rotate query part
×no parametersapply_rotary_pos_emb_interleave(q_rot, k_rot, cos, sin)
Rotate each feature pair by its position’s angle.
- in
- [B batch, 64 heads, T positions, 64 rotary] [T positions, 32 pairs]
- out
- [B batch, 64 heads, T positions, 64 rotary]
Explanation
Pair is features and ; position turns it by . The output lists the rotated first features of all pairs, then the second (modeling_glm_moe_dsa.py 156–160); queries and keys share the order, so their products are unchanged.
Queries and keys turn by the same angles, so a query at position and a key at position meet in a product that depends on their positions only through .
Codemodeling_glm_moe_dsa.py 68–405
def apply_rotary_pos_emb_interleave(q, k, cos, sin, position_ids=None, unsqueeze_dim=1):
r"""
Applies interleaved Rotary Position Embedding to the query and key tensors.
DeepSeek lays the rotary dimensions out in interleaved pairs `(x0, x1), (x2, x3), ...`, each rotated by a
single frequency. We compute that rotation directly on the even/odd slices instead of de-interleaving with a
`view`/`transpose`/`reshape`; the output is bit-identical to the de-interleaved `rotate_half` formulation while
avoiding the extra contiguous copy.
Args:
q (`torch.Tensor`): The query tensor.
k (`torch.Tensor`): The key tensor.
cos (`torch.Tensor`): The cosine part of the rotary embedding.
sin (`torch.Tensor`): The sine part of the rotary embedding.
position_ids (`torch.Tensor`):
The position indices of the tokens corresponding to the query and key tensors. For example, this can be
used to pass offsetted position ids when working with a KV-cache.
unsqueeze_dim (`int`, *optional*, defaults to 1):
The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
Returns:
`tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
"""
# `cos`/`sin` are `cat(freqs, freqs)`; the first half holds the per-pair angle.
cos = cos[..., : cos.shape[-1] // 2].unsqueeze(unsqueeze_dim)
sin = sin[..., : sin.shape[-1] // 2].unsqueeze(unsqueeze_dim)
q1, q2 = q[..., 0::2], q[..., 1::2]
k1, k2 = k[..., 0::2], k[..., 1::2]
q_embed = torch.cat([q1 * cos - q2 * sin, q2 * cos + q1 * sin], dim=-1)
k_embed = torch.cat([k1 * cos - k2 * sin, k2 * cos + k1 * sin], dim=-1)
return q_embed, k_embed q_rot, k_rot = apply_rotary_pos_emb_interleave(q_rot, k_rot, cos, sin, unsqueeze_dim=2) q_rot, k_rot = apply_rotary_pos_emb_interleave(q_rot, k_rot, cos, sin)class GlmMoeDsaRotaryEmbedding(nn.Module):
@deprecate_kwarg("device", version="5.18")
def __init__(self, config: GlmMoeDsaConfig, device=None):
super().__init__()
self.max_seq_len_cached = config.max_position_embeddings
self.original_max_seq_len = config.max_position_embeddings
self.config = config
self.rope_type = self.config.rope_parameters["rope_type"]
rope_init_fn: Callable = self.compute_default_rope_parameters
if self.rope_type != "default":
rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type]
inv_freq, self.attention_scaling = rope_init_fn(self.config, device)
self.inv_freq = nn.Buffer(inv_freq, persistent=False)
self.original_inv_freq = nn.Buffer(inv_freq.clone(), persistent=False)
@staticmethod
@deprecate_kwarg("device", version="5.18")
def compute_default_rope_parameters(config: GlmMoeDsaConfig, device=None, **kwargs) -> tuple[torch.Tensor, float]:
"""
Computes the inverse frequencies according to the original RoPE implementation
Args:
config ([`~transformers.PreTrainedConfig`]):
The model configuration.
Returns:
Tuple of (`torch.Tensor`, `float`), containing the inverse frequencies for the RoPE embeddings and the
post-processing scaling factor applied to the computed cos/sin (unused in this type of RoPE).
"""
base = config.rope_parameters["rope_theta"]
dim = getattr(config, "head_dim", None) or config.hidden_size // config.num_attention_heads
attention_factor = 1.0 # Unused in this type of RoPE
# Compute the inverse frequencies
inv_freq = 1.0 / (base ** (torch.arange(0, dim, 2, dtype=torch.float) / dim))
return inv_freq.to(device), attention_factor
@torch.no_grad()
@dynamic_rope_update # power user: used with advanced RoPE types (e.g. dynamic rope)
def forward(self, x, position_ids):
inv_freq_expanded = (
self.inv_freq[None, :, None].expand(position_ids.shape[0], -1, 1).to(dtype=torch.float, device=x.device)
)
position_ids_expanded = position_ids[:, None, :].float()
device_type = x.device.type if isinstance(x.device.type, str) else "cpu"
# Disable any outside autocast context if any, to really force fp32
with maybe_autocast(device_type=device_type, enabled=False):
freqs = (inv_freq_expanded @ position_ids_expanded).transpose(1, 2)
emb = torch.cat((freqs, freqs), dim=-1)
cos = emb.cos() * self.attention_scaling
sin = emb.sin() * self.attention_scaling
return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)Sources2
Direct evidence
Interleaved RoPE rotates consecutive feature pairs (x0, x1), (x2, x3), … by one frequency each; attention and the indexer both call it.
apply-rope · huggingface/transformers / modeling_glm_moe_dsa.py
Pinned revision 5e4d6304de55 ↗ · lines 125–405
Read code excerpt
def apply_rotary_pos_emb_interleave(q, k, cos, sin, position_ids=None, unsqueeze_dim=1):
r"""
Applies interleaved Rotary Position Embedding to the query and key tensors.
DeepSeek lays the rotary dimensions out in interleaved pairs `(x0, x1), (x2, x3), ...`, each rotated by a
single frequency. We compute that rotation directly on the even/odd slices instead of de-interleaving with a
`view`/`transpose`/`reshape`; the output is bit-identical to the de-interleaved `rotate_half` formulation while
avoiding the extra contiguous copy.
Args:
q (`torch.Tensor`): The query tensor.
k (`torch.Tensor`): The key tensor.
cos (`torch.Tensor`): The cosine part of the rotary embedding.
sin (`torch.Tensor`): The sine part of the rotary embedding.
position_ids (`torch.Tensor`):
The position indices of the tokens corresponding to the query and key tensors. For example, this can be
used to pass offsetted position ids when working with a KV-cache.
unsqueeze_dim (`int`, *optional*, defaults to 1):
The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
Returns:
`tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
"""
# `cos`/`sin` are `cat(freqs, freqs)`; the first half holds the per-pair angle.
cos = cos[..., : cos.shape[-1] // 2].unsqueeze(unsqueeze_dim)
sin = sin[..., : sin.shape[-1] // 2].unsqueeze(unsqueeze_dim)
q1, q2 = q[..., 0::2], q[..., 1::2]
k1, k2 = k[..., 0::2], k[..., 1::2]
q_embed = torch.cat([q1 * cos - q2 * sin, q2 * cos + q1 * sin], dim=-1)
k_embed = torch.cat([k1 * cos - k2 * sin, k2 * cos + k1 * sin], dim=-1)
return q_embed, k_embed… lines 162–231 omitted …
q_rot, k_rot = apply_rotary_pos_emb_interleave(q_rot, k_rot, cos, sin, unsqueeze_dim=2)… lines 233–404 omitted …
q_rot, k_rot = apply_rotary_pos_emb_interleave(q_rot, k_rot, cos, sin)Direct evidence
Rotary coefficients: default RoPE, inverse frequencies θ^(−2j/d) over the rotary slice, cosine and sine computed in float32 for the current positions and cast to the activations’ type, with no rescaling (the attention factor is 1).
rope · huggingface/transformers / modeling_glm_moe_dsa.py
Pinned revision 5e4d6304de55 ↗ · lines 68–122
Read code excerpt
class GlmMoeDsaRotaryEmbedding(nn.Module):
@deprecate_kwarg("device", version="5.18")
def __init__(self, config: GlmMoeDsaConfig, device=None):
super().__init__()
self.max_seq_len_cached = config.max_position_embeddings
self.original_max_seq_len = config.max_position_embeddings
self.config = config
self.rope_type = self.config.rope_parameters["rope_type"]
rope_init_fn: Callable = self.compute_default_rope_parameters
if self.rope_type != "default":
rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type]
inv_freq, self.attention_scaling = rope_init_fn(self.config, device)
self.inv_freq = nn.Buffer(inv_freq, persistent=False)
self.original_inv_freq = nn.Buffer(inv_freq.clone(), persistent=False)
@staticmethod
@deprecate_kwarg("device", version="5.18")
def compute_default_rope_parameters(config: GlmMoeDsaConfig, device=None, **kwargs) -> tuple[torch.Tensor, float]:
"""
Computes the inverse frequencies according to the original RoPE implementation
Args:
config ([`~transformers.PreTrainedConfig`]):
The model configuration.
Returns:
Tuple of (`torch.Tensor`, `float`), containing the inverse frequencies for the RoPE embeddings and the
post-processing scaling factor applied to the computed cos/sin (unused in this type of RoPE).
"""
base = config.rope_parameters["rope_theta"]
dim = getattr(config, "head_dim", None) or config.hidden_size // config.num_attention_heads
attention_factor = 1.0 # Unused in this type of RoPE
# Compute the inverse frequencies
inv_freq = 1.0 / (base ** (torch.arange(0, dim, 2, dtype=torch.float) / dim))
return inv_freq.to(device), attention_factor
@torch.no_grad()
@dynamic_rope_update # power user: used with advanced RoPE types (e.g. dynamic rope)
def forward(self, x, position_ids):
inv_freq_expanded = (
self.inv_freq[None, :, None].expand(position_ids.shape[0], -1, 1).to(dtype=torch.float, device=x.device)
)
position_ids_expanded = position_ids[:, None, :].float()
device_type = x.device.type if isinstance(x.device.type, str) else "cpu"
# Disable any outside autocast context if any, to really force fp32
with maybe_autocast(device_type=device_type, enabled=False):
freqs = (inv_freq_expanded @ position_ids_expanded).transpose(1, 2)
emb = torch.cat((freqs, freqs), dim=-1)
cos = emb.cos() * self.attention_scaling
sin = emb.sin() * self.attention_scaling
return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)