RoPE coefficients
×tensorcos, sin
Rotation coefficients for the current sequence, supplied to every block.
- shape
- [T positions, 32 pairs]
Sources
Contextual evidence from Generate RoPE coefficients
Rotary coefficients: the YaRN correction range in rotary pairs, the linear ramp between base and interpolated frequencies, and cos/sin tables scaled by the ratio of the two YaRN corrections.
rope · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 226–327
Read code excerpt
def yarn_find_correction_dim(
num_rotations, dim, base=10000, max_position_embeddings=2048
):
return (dim * math.log(max_position_embeddings / (num_rotations * 2 * math.pi))) / (
2 * math.log(base)
)
# Find dim range bounds based on rotations
def yarn_find_correction_range(
low_rot, high_rot, dim, base=10000, max_position_embeddings=2048
):
low = math.floor(
yarn_find_correction_dim(low_rot, dim, base, max_position_embeddings)
)
high = math.ceil(
yarn_find_correction_dim(high_rot, dim, base, max_position_embeddings)
)
return max(low, 0), min(high, dim - 1) # Clamp values just in case
def yarn_get_mscale(scale=1, mscale=1):
if scale <= 1:
return 1.0
return 0.1 * mscale * math.log(scale) + 1.0
def yarn_linear_ramp_mask(min, max, dim):
if min == max:
max += 0.001 # Prevent singularity
linear_func = (torch.arange(dim, dtype=torch.float32) - min) / (max - min)
ramp_func = torch.clamp(linear_func, 0, 1)
return ramp_func… lines 260–284 omitted …
def _set_cos_sin_cache(self, seq_len, device, dtype):
self.max_seq_len_cached = seq_len
dim = self.dim
freq_extra = 1.0 / (
self.base
** (torch.arange(0, dim, 2, dtype=torch.float32, device=device) / dim)
)
freq_inter = 1.0 / (
self.scaling_factor
* self.base
** (torch.arange(0, dim, 2, dtype=torch.float32, device=device) / dim)
)
low, high = yarn_find_correction_range(
self.beta_fast,
self.beta_slow,
dim,
self.base,
self.original_max_position_embeddings,
)
inv_freq_mask = 1.0 - yarn_linear_ramp_mask(low, high, dim // 2).to(
device=device, dtype=torch.float32
)
inv_freq = freq_inter * (1 - inv_freq_mask) + freq_extra * inv_freq_mask
self.register_buffer("inv_freq", inv_freq, persistent=False)
t = torch.arange(seq_len, device=device, dtype=torch.float32)
freqs = torch.outer(t, inv_freq)
_mscale = float(
yarn_get_mscale(self.scaling_factor, self.mscale)
/ yarn_get_mscale(self.scaling_factor, self.mscale_all_dim)
)
emb = torch.cat((freqs, freqs), dim=-1)
self.register_buffer(
"cos_cached", (emb.cos() * _mscale).to(dtype), persistent=False
)
self.register_buffer(
"sin_cached", (emb.sin() * _mscale).to(dtype), persistent=False
)Contextual evidence from Generate RoPE coefficients
YaRN RoPE as the implementation builds it: the YaRN class and its defaults, the softmax scale (1/√192 times the square of the YaRN attention correction for mscale_all_dim), and the choice of YaRN whenever the configuration’s rope_scaling type is yarn.
model-args · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 262–742
Read code excerpt
class DeepseekV3YarnRotaryEmbedding(DeepseekV3RotaryEmbedding):
def __init__(
self,
dim,
max_position_embeddings=2048,
base=10000,
device=None,
scaling_factor=1.0,
original_max_position_embeddings=4096,
beta_fast=32,
beta_slow=1,
mscale=1,
mscale_all_dim=0,
):
self.scaling_factor = scaling_factor
self.original_max_position_embeddings = original_max_position_embeddings
self.beta_fast = beta_fast
self.beta_slow = beta_slow
self.mscale = mscale
self.mscale_all_dim = mscale_all_dim
super().__init__(dim, max_position_embeddings, base, device)… lines 284–689 omitted …
self.softmax_scale = self.q_head_dim ** (-0.5)
if self.config.rope_scaling is not None:
mscale_all_dim = self.config.rope_scaling.get("mscale_all_dim", 0)
scaling_factor = self.config.rope_scaling["factor"]
if mscale_all_dim:
mscale = yarn_get_mscale(scaling_factor, mscale_all_dim)
self.softmax_scale = self.softmax_scale * mscale * mscale… lines 697–697 omitted …
def _init_rope(self):
if self.config.rope_scaling is None:
self.rotary_emb = DeepseekV3RotaryEmbedding(
self.qk_rope_head_dim,
max_position_embeddings=self.max_position_embeddings,
base=self.rope_theta,
)
else:
scaling_type = self.config.rope_scaling["type"]
scaling_factor = self.config.rope_scaling["factor"]
if scaling_type == "linear":
self.rotary_emb = DeepseekV3LinearScalingRotaryEmbedding(
self.qk_rope_head_dim,
max_position_embeddings=self.max_position_embeddings,
scaling_factor=scaling_factor,
base=self.rope_theta,
)
elif scaling_type == "dynamic":
self.rotary_emb = DeepseekV3DynamicNTKScalingRotaryEmbedding(
self.qk_rope_head_dim,
max_position_embeddings=self.max_position_embeddings,
scaling_factor=scaling_factor,
base=self.rope_theta,
)
elif scaling_type == "yarn":
kwargs = {
key: self.config.rope_scaling[key]
for key in [
"original_max_position_embeddings",
"beta_fast",
"beta_slow",
"mscale",
"mscale_all_dim",
]
if key in self.config.rope_scaling
}
self.rotary_emb = DeepseekV3YarnRotaryEmbedding(
self.qk_rope_head_dim,
max_position_embeddings=self.max_position_embeddings,
scaling_factor=scaling_factor,
base=self.rope_theta,
**kwargs,
)
else:
raise ValueError(f"Unknown RoPE scaling type {scaling_type}")Contextual evidence from Transformer blocks
The model embeds tokens, numbers positions from the cached length, builds a 4D causal mask, applies all blocks, normalizes and projects to vocabulary logits with an untied head, computing every position’s logits in float32.
transformer · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 1360–1616
Read code excerpt
self.embed_tokens = nn.Embedding(
config.vocab_size, config.hidden_size, self.padding_idx
)
self.layers = nn.ModuleList(
[
DeepseekV3DecoderLayer(config, layer_idx)
for layer_idx in range(config.num_hidden_layers)
]
)
self._use_flash_attention_2 = config._attn_implementation == "flash_attention_2"
self.norm = DeepseekV3RMSNorm(config.hidden_size, eps=config.rms_norm_eps)… lines 1371–1422 omitted …
past_key_values_length = 0
if use_cache:
use_legacy_cache = not isinstance(past_key_values, Cache)
if use_legacy_cache:
past_key_values = DynamicCache.from_legacy_cache(past_key_values)
past_key_values_length = past_key_values.get_usable_length(seq_length)
if position_ids is None:
device = input_ids.device if input_ids is not None else inputs_embeds.device
position_ids = torch.arange(
past_key_values_length,
seq_length + past_key_values_length,
dtype=torch.long,
device=device,
)
position_ids = position_ids.unsqueeze(0)… lines 1439–1442 omitted …
if self._use_flash_attention_2:
# 2d mask is passed through the layers
attention_mask = (
attention_mask
if (attention_mask is not None and 0 in attention_mask)
else None
)
else:
# 4d mask is passed through the layers
attention_mask = _prepare_4d_causal_attention_mask(
attention_mask,
(batch_size, seq_length),
inputs_embeds,
past_key_values_length,
)… lines 1458–1521 omitted …
self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)… lines 1523–1613 omitted …
hidden_states = outputs[0]
logits = self.lm_head(hidden_states)
logits = logits.float()Contextual evidence from Transformer blocks
A block applies input RMSNorm, attention and a residual addition, then post-attention RMSNorm, the FFN and a second residual addition; the first first_k_dense_replace blocks use the dense MLP, the rest MoE.
block · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 1152–1218
Read code excerpt
self.mlp = (
DeepseekV3MoE(config)
if (
config.n_routed_experts is not None
and layer_idx >= config.first_k_dense_replace
and layer_idx % config.moe_layer_freq == 0
)
else DeepseekV3MLP(config)
)
self.input_layernorm = DeepseekV3RMSNorm(
config.hidden_size, eps=config.rms_norm_eps
)
self.post_attention_layernorm = DeepseekV3RMSNorm(
config.hidden_size, eps=config.rms_norm_eps
)… lines 1167–1197 omitted …
residual = hidden_states
hidden_states = self.input_layernorm(hidden_states)
# Self Attention
hidden_states, self_attn_weights, present_key_value = self.self_attn(
hidden_states=hidden_states,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_value=past_key_value,
output_attentions=output_attentions,
use_cache=use_cache,
**kwargs,
)
hidden_states = residual + hidden_states
# Fully Connected
residual = hidden_states
hidden_states = self.post_attention_layernorm(hidden_states)
hidden_states = self.mlp(hidden_states)
hidden_states = residual + hidden_states