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dots.llm1

Llama's pre-norm block with each query and key head RMS-normed, a dense MLP on block 0, and on every block after it a mixture whose experts are chosen by a sigmoid plus a selection bias that the weights leave out, beside a shared expert every token runs through.

The block

01 · the residual stream

One block of the stack. Hover any part for its nnterp name; click to pin the card. The slider picks a block, each tick's color gives its block's shape, and the diagram redraws for the block picked.

embed_tokenstoken_embeddings
→
layers× 62
→
normfinal_norm_output
→
lm_headlm_head_output
→
logitsthe output
i = 0

identity layers[i].input + self_attn.attention_output + mlp.mlp_output == layer_output

The API

02 · support()

Values, by host

⚠︎ marks a value this checkpoint has only under some load: hover it for the condition.

model Dots1ForCausalLMlayoutwhat it isread at
logits Logits [batch seq vocab_size] The logits the model returns, after anything it does past lm_head (a softcap, a scale)

the module's own output

token_embeddings Residual [batch seq hidden_size] The embedding module's output; layers[0].input is what enters the first block

the child module embed_tokens's output

final_norm_output Residual [batch seq hidden_size] The residual stream after the final norm, what lm_head reads

the child module norm's output

lm_head_output Logits [batch seq vocab_size] The head's logits before anything the model does past lm_head (a softcap, a scale)

the child module lm_head's output

next_token_probs NextTokenProbs [batch vocab_size] The next-token distribution at the last position; derived, read-only

the module's own output

input_ids Tokens [batch seq] The token ids the model was called with

the module's own input

attention_mask Tokens [batch seq] The attention mask the model was called with; zeros are padding

the module's own input

input_size scalar [batch, seq] of the current call; read-only

the module's own input

model.layers[i] Dots1DecoderLayerlayoutwhat it isread at
layer_input Residual [batch seq hidden_size] The residual stream entering the block

the module's own input

attention_norm_output Residual [batch seq hidden_size] The normed stream entering the attention

the child module input_layernorm's output

layer_mid Residual [batch seq hidden_size] The residual stream after the attention add

the child module post_attention_layernorm's input

mlp_norm_output Residual [batch seq hidden_size] The normed stream entering the MLP

the child module post_attention_layernorm's output

mlp_input Residual [batch seq hidden_size] What the MLP is called with

the child module mlp's input

layer_output Residual [batch seq hidden_size] The residual stream leaving the block, a tensor even when the block returns a tuple

the module's own output

model.layers[i].self_attn Dots1Attentionlayoutwhat it isread at
⚠︎attention_queries Queries [batch num_heads seq qk_head_dim] The queries entering attention

inside the forward: the arguments of attention_interface_1, element 1

⚠︎attention_keys Keys [batch num_kv_heads seq qk_head_dim] The keys entering attention

inside the forward: the arguments of attention_interface_1, element 2

⚠︎attention_values Values [batch num_kv_heads seq head_dim] The values entering attention

inside the forward: the arguments of attention_interface_1, element 3

⚠︎attention_scores Pattern [batch num_heads query key] The attention scores entering the softmax, masked

inside the forward: the input of nn_functional_softmax_0 inside attention_interface_1

attention_premix HeadOutputs [batch seq num_heads head_dim] Every head's output side by side, as the output projection takes it

the child module o_proj's input

attention_output Residual [batch seq hidden_size] What the attention adds to the residual stream

the module's own output

⚠︎attention_probabilities Pattern [batch num_heads query key] The attention pattern the values are mixed with

inside the forward: the output of nn_functional_dropout_0 inside attention_interface_1

⚠︎attention_head_outputs HeadOutputs [batch seq num_heads head_dim] The per-head outputs before the output projection

inside the forward: the output of attention_interface_1, element 0

model.layers[i].mlp Dots1MLP / Dots1MoElayoutwhat it isread at
⚠︎mlp_activation Neurons [batch seq intermediate_size] The activation function's output

the child module act_fn's output

⚠︎mlp_neurons Neurons [batch seq intermediate_size] What the down projection receives: act(gate)·up on a gated MLP, the activation itself otherwise

the child module down_proj's input

mlp_output Residual [batch seq hidden_size] What the MLP adds to the residual stream

the module's own output

router_logits RouterLogits [batch seq num_experts] The router's logits, one per expert, before the scoring

inside router's forward: the output of F_linear_0

expert_weights ExpertWeights [batch seq top_k] The weight each selected expert's output is scaled by

the child module experts's inputs, element 2

expert_indices ExpertIndices [batch seq top_k] The expert each routing slot sends the token to

the child module experts's inputs, element 1

expert_outputs ExpertOutputs [batch seq top_k hidden_size] Each routing slot's weighted expert output

inside experts's forward: the output of weighted_out_view_0 inside experts_forward_1

routed_output Residual [batch seq hidden_size] The routed experts' combined output

the child module experts's output

shared_expert_output Residual [batch seq hidden_size] The shared expert's output

the child module shared_experts's output

Printout

What print(model) shows on rednote-hilab/dots.llm1.base: the native modules, standard names and every standard value with its layout.

Dots1ForCausalLM(
  (lm_head): Linear(in_features=4096, out_features=152064, bias=False)
  (generator): Generator(
    (streamer): Streamer()
  )
  (embed_tokens): Embedding(152064, 4096)
  (layers): ModuleList(
    (0): Dots1DecoderLayer(
      (self_attn): Dots1Attention(
        (q_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (k_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (v_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (o_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (q_norm): Dots1RMSNorm((128,), eps=1e-05)
        (k_norm): Dots1RMSNorm((128,), eps=1e-05)
        (attention_queries) -> Queries [batch num_heads seq qk_head_dim]: The queries entering attention
        (attention_keys) -> Keys [batch num_kv_heads seq qk_head_dim]: The keys entering attention
        (attention_values) -> Values [batch num_kv_heads seq head_dim]: The values entering attention
        (attention_scores) -> Pattern [batch num_heads query key]: The attention scores entering the softmax, masked
        (attention_premix) -> HeadOutputs [batch seq num_heads head_dim]: Every head's output side by side, as the output projection takes it
        (attention_output) -> Residual [batch seq hidden_size]: What the attention adds to the residual stream
        (attention_probabilities) -> Pattern [batch num_heads query key]: The attention pattern the values are mixed with
        (attention_head_outputs) -> HeadOutputs [batch seq num_heads head_dim]: The per-head outputs before the output projection
      )
      (mlp): Dots1MLP(
        (gate_proj): Linear(in_features=4096, out_features=10944, bias=False)
        (up_proj): Linear(in_features=4096, out_features=10944, bias=False)
        (down_proj): Linear(in_features=10944, out_features=4096, bias=False)
        (act_fn): SiLUActivation()
        (mlp_activation) -> Neurons [batch seq intermediate_size]: The activation function's output
        (mlp_neurons) -> Neurons [batch seq intermediate_size]: What the down projection receives: act(gate)·up on a gated MLP, the activation itself otherwise
        (mlp_output) -> Residual [batch seq hidden_size]: What the MLP adds to the residual stream
      )
      (input_layernorm): Dots1RMSNorm((4096,), eps=1e-05)
      (post_attention_layernorm): Dots1RMSNorm((4096,), eps=1e-05)
      (layer_input) -> Residual [batch seq hidden_size]: The residual stream entering the block
      (attention_norm_output) -> Residual [batch seq hidden_size]: The normed stream entering the attention
      (layer_mid) -> Residual [batch seq hidden_size]: The residual stream after the attention add
      (mlp_norm_output) -> Residual [batch seq hidden_size]: The normed stream entering the MLP
      (mlp_input) -> Residual [batch seq hidden_size]: What the MLP is called with
      (layer_output) -> Residual [batch seq hidden_size]: The residual stream leaving the block, a tensor even when the block returns a tuple
    )
    (1-61): 61 x Dots1DecoderLayer(
      (self_attn): Dots1Attention(
        (q_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (k_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (v_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (o_proj): Linear(in_features=4096, out_features=4096, bias=False)
        (q_norm): Dots1RMSNorm((128,), eps=1e-05)
        (k_norm): Dots1RMSNorm((128,), eps=1e-05)
        (attention_queries) -> Queries [batch num_heads seq qk_head_dim]: The queries entering attention
        (attention_keys) -> Keys [batch num_kv_heads seq qk_head_dim]: The keys entering attention
        (attention_values) -> Values [batch num_kv_heads seq head_dim]: The values entering attention
        (attention_scores) -> Pattern [batch num_heads query key]: The attention scores entering the softmax, masked
        (attention_premix) -> HeadOutputs [batch seq num_heads head_dim]: Every head's output side by side, as the output projection takes it
        (attention_output) -> Residual [batch seq hidden_size]: What the attention adds to the residual stream
        (attention_probabilities) -> Pattern [batch num_heads query key]: The attention pattern the values are mixed with
        (attention_head_outputs) -> HeadOutputs [batch seq num_heads head_dim]: The per-head outputs before the output projection
      )
      (mlp): Dots1MoE(
        (experts): Dots1Experts(
          (act_fn): SiLUActivation()
        )
        (router/gate): Dots1TopkRouter()
        (shared_experts): Dots1MLP(
          (gate_proj): Linear(in_features=4096, out_features=2816, bias=False)
          (up_proj): Linear(in_features=4096, out_features=2816, bias=False)
          (down_proj): Linear(in_features=2816, out_features=4096, bias=False)
          (act_fn): SiLUActivation()
          (mlp_activation) -> Neurons [batch seq intermediate_size]: The activation function's output
          (mlp_neurons) -> Neurons [batch seq intermediate_size]: What the down projection receives: act(gate)·up on a gated MLP, the activation itself otherwise
          (mlp_output) -> Residual [batch seq hidden_size]: What the MLP adds to the residual stream
        )
        (mlp_activation) -> Neurons [batch seq intermediate_size]: The activation function's output
        (mlp_neurons) -> Neurons [batch seq intermediate_size]: What the down projection receives: act(gate)·up on a gated MLP, the activation itself otherwise
        (router_logits) -> RouterLogits [batch seq num_experts]: The router's logits, one per expert, before the scoring
        (expert_weights) -> ExpertWeights [batch seq top_k]: The weight each selected expert's output is scaled by
        (expert_indices) -> ExpertIndices [batch seq top_k]: The expert each routing slot sends the token to
        (expert_outputs) -> ExpertOutputs [batch seq top_k hidden_size]: Each routing slot's weighted expert output
        (routed_output) -> Residual [batch seq hidden_size]: The routed experts' combined output
        (shared_expert_output) -> Residual [batch seq hidden_size]: The shared expert's output
        (mlp_output) -> Residual [batch seq hidden_size]: What the MLP adds to the residual stream
      )
      (input_layernorm): Dots1RMSNorm((4096,), eps=1e-05)
      (post_attention_layernorm): Dots1RMSNorm((4096,), eps=1e-05)
      (layer_input) -> Residual [batch seq hidden_size]: The residual stream entering the block
      (attention_norm_output) -> Residual [batch seq hidden_size]: The normed stream entering the attention
      (layer_mid) -> Residual [batch seq hidden_size]: The residual stream after the attention add
      (mlp_norm_output) -> Residual [batch seq hidden_size]: The normed stream entering the MLP
      (mlp_input) -> Residual [batch seq hidden_size]: What the MLP is called with
      (layer_output) -> Residual [batch seq hidden_size]: The residual stream leaving the block, a tensor even when the block returns a tuple
    )
  )
  (norm): Dots1RMSNorm((4096,), eps=1e-05)
  (logits) -> Logits [batch seq vocab_size]: The logits the model returns, after anything it does past lm_head (a softcap, a scale)
  (token_embeddings) -> Residual [batch seq hidden_size]: The embedding module's output; layers[0].input is what enters the first block
  (final_norm_output) -> Residual [batch seq hidden_size]: The residual stream after the final norm, what lm_head reads
  (lm_head_output) -> Logits [batch seq vocab_size]: The head's logits before anything the model does past lm_head (a softcap, a scale)
  (next_token_probs) -> NextTokenProbs [batch vocab_size]: The next-token distribution at the last position; derived, read-only
  (input_ids) -> Tokens [batch seq]: The token ids the model was called with
  (attention_mask) -> Tokens [batch seq]: The attention mask the model was called with; zeros are padding
  (input_size): [batch, seq] of the current call; read-only
)

Config

model.num_layers62
model.hidden_size4096
model.num_heads32
model.num_kv_heads32
model.head_dim128
model.qk_head_dim128
model.vocab_size152064
model.intermediate_size10944
architecturesDots1ForCausalLM
num_hidden_layers62
hidden_size4096
intermediate_size10944
num_attention_heads32
num_key_value_heads32
vocab_size152064
max_position_embeddings32768
hidden_actsilu
rms_norm_eps1e-05
tie_word_embeddingsFalse
dtypebfloat16
first_k_dense_replace1
moe_intermediate_size1408
n_routed_experts128
num_experts_per_tok6
n_shared_experts2
routed_scaling_factor2.5
norm_topk_probTrue
attention_biasFalse
use_sliding_windowFalse
max_window_layers62
n_group1
topk_group1

The Notes

03 · what to know before you run

The block, in order

h   = x + self_attn(input_layernorm(x))       # q_norm, k_norm per head inside
out = h + mlp(post_attention_layernorm(h))    # dense on block 0, a mixture after

Llama's pre-norm block and Llama's names. first_k_dense_replace is 1 on both checkpoints: block 0 has a dense MLP 10944 wide, and the other 61 a mixture. Nothing norms a sublayer's output, so attention_output is o_proj's output and mlp_output the mixture's, shared expert included. The identity is the plain sum on both kinds of block:

with model.trace(prompt):
    x = model.layers[1].input.save()
    attn = model.layers[1].self_attn.attention_output.save()
    mlp = model.layers[1].mlp.mlp_output.save()
    out = model.layers[1].layer_output.save()

torch.testing.assert_close(x + attn + mlp, out)

Queries and keys are normed per head

q_norm and k_norm are RMSNorms over each head's 128 dimensions, applied before the rotary; attention_queries and attention_keys are read after both, and an edit there reaches the attention as written. An edit to one head's slice of q_proj.output stays in that head, and the norm rescales it. There are 32 key/value heads for 32 query heads, so no grouping. Every block attends over the whole prefix (sliding_window is null), with rotary at rope_theta 1e7. The attention interior needs attn_implementation="eager".

The router: sigmoid scores, a selection bias, weights summing to 2.5

128 routed experts, 6 per token. router_logits are the router's float32 logits, before the sigmoid and before the selection bias (router.e_score_correction_bias). The bias is added to the sigmoids only to choose; n_group and topk_group are 1, so every expert competes. expert_weights are the chosen experts' sigmoids without the bias, renormalized to sum to one (norm_topk_prob) and multiplied by routed_scaling_factor 2.5, so they sum to 2.5 at every token:

moe = model.layers[1].mlp
with model.trace(prompt):
    logits = moe.router_logits.save()
    w = moe.expert_weights.save()
    idx = moe.expert_indices.save()

chosen = logits.sigmoid().gather(-1, idx)
torch.testing.assert_close(w, chosen / chosen.sum(-1, keepdim=True) * 2.5)

A written router_logits moves the choice and the weights; a written bias moves only the choice.

The shared expert runs after the routed ones

n_shared_experts is 2, merged into one Dots1MLP (mlp.shared_experts) of width 2 × 1408. It reads the mixture's input and runs after the routed experts, so in one trace read routed_output before shared_expert_output. Their sum is mlp_output:

with model.trace(prompt):
    routed = moe.routed_output.save()
    shared = moe.shared_expert_output.save()
    out = moe.mlp_output.save()

torch.testing.assert_close(routed + shared, out)

Ablating an expert

Zero the weight of every slot that chose it. The token's other weights keep their values, so its weights then sum to less than 2.5, and mlp_output changes on exactly the tokens that chose it:

with model.trace(prompt):
    idx = moe.expert_indices.save()
    clean = moe.mlp_output.save()
with model.trace(prompt):
    moe.expert_weights = moe.expert_weights.masked_fill(moe.expert_indices == 3, 0)
    ablated = moe.mlp_output.save()

assert torch.equal((ablated != clean).any(-1), (idx == 3).any(-1))

Block 0 has a dense MLP: support() reports every mixture value missing there.

From the family module

04 · nnterp/families/dots1.py

dots.llm1 (Dots1ForCausalLM).

Llama's tree and Llama's block: model.{embed_tokens, layers[i].{input_layernorm, self_attn, post_attention_layernorm, mlp}, norm} and lm_head, the residual added in the block, attention through the shared eager forward. The attention norms its queries and keys per head (q_norm, k_norm) before the rotary embedding. The first first_k_dense_replace blocks have a dense MLP, the rest a mixture of experts that adds a shared expert (mlp.shared_experts, itself a Dots1MLP) before it returns; the experts are moe_intermediate_size wide.