Qwen3.5-MoE¶

The Mixture-of-Experts variant of Qwen3.5, ported to pure Keras 3. It keeps the Gated-DeltaNet / full-attention hybrid and replaces the MLP with a routed expert bank.

Memory is governed by total parameters, not active ones.

Variants¶

Load any of these with from_weights("<variant>").

Variant	Hub
`qwen3-next-80b-a3b-instruct`	`Qwen/Qwen3-Next-80B-A3B-Instruct`
`qwen3-next-80b-a3b-thinking`	`Qwen/Qwen3-Next-80B-A3B-Thinking`

API¶

`Qwen35MoeModel`¶

The decoder backbone, no LM head. Returns {"last_hidden_state": (batch, seq, embed_dim)}.

Arg	Default	Meaning
`vocab_size`	`151936`	token vocabulary size
`embed_dim`	`2048`	model width
`mlp_dim`	`5120`	MLP inner width
`num_layers`	`48`	decoder blocks
`num_heads`	`16`	query heads
`num_kv_heads`	`2`	key/value heads (GQA)
`head_dim`	`256`	per-head width
`norm_eps`	`1e-06`	RMSNorm epsilon
`rope_theta`	`10000000.0`	rotary base frequency
`partial_rotary_factor`	`0.25`	fraction of each head that gets rotated
`tie_embeddings`	`False`	reuse the embedding matrix as the LM head
`full_attention_interval`	`4`
`linear_conv_kernel_dim`	`4`
`linear_key_head_dim`	`128`
`linear_value_head_dim`	`128`
`linear_num_key_heads`	`16`
`linear_num_value_heads`	`32`
`num_experts`	`512`	expert count
`num_experts_per_tok`	`10`	experts routed per token
`moe_mlp_dim`	`512`	per-expert inner width
`shared_mlp_dim`	`512`
`norm_topk_prob`	`True`
`decoder_sparse_step`	`1`
`mlp_only_layers`	`()`

`Qwen35MoeGenerate`¶

Qwen35MoeModel plus a (tied) LM head. Returns {"logits": (batch, seq, vocab_size)} and adds .generate(). Same constructor arguments as Qwen35MoeModel.

generate(input_ids, attention_mask=None, max_new_tokens=None,
         eos_token_id=None, sampler=None, seed=None, **prefill_inputs)

Arg	Default	Meaning
`input_ids`	required	`(batch, seq)` token ids
`attention_mask`	`None`	`(batch, seq)` 1 = keep, 0 = padding
`max_new_tokens`	`None`	tokens to generate
`eos_token_id`	`None`	stop token (defaults to the tokenizer's)
`sampler`	`None`	sampling strategy; greedy when unset
`seed`	`None`	seed for stochastic samplers

`Qwen35MoeTokenizer`¶

Tokenizer on the tokenizers backend.

Qwen35MoeTokenizer(hf_id=None, tokenizer_file=None)

Arg	Default	Meaning
`hf_id`	`None`	Hub repo to pull the tokenizer files from
`tokenizer_file`	`None`	explicit path to a `tokenizer.json`

Calling it returns {"input_ids", "attention_mask"}, padded across the batch. It accepts a plain string, a list of strings (a batch), or a chat-message list, which is routed through apply_chat_template automatically. Decode with .decode(ids) for one sequence or .batch_decode(ids) for a batch.

End-to-end example¶

Single input¶

import os
os.environ["KERAS_BACKEND"] = "torch"   # or "jax" / "tensorflow"

from kerasformers.models.qwen3_5_moe import Qwen35MoeGenerate, Qwen35MoeTokenizer

model = Qwen35MoeGenerate.from_weights("qwen3-next-80b-a3b-instruct")
tokenizer = Qwen35MoeTokenizer.from_weights("qwen3-next-80b-a3b-instruct")

inputs = tokenizer([{"role": "user", "content": "Explain rotary embeddings in one sentence."}])
outputs = model.generate(**inputs, max_new_tokens=64)

print(tokenizer.decode(outputs[0]))

Batch¶

Pass a list of strings. The tokenizer pads them and generate runs the batch together:

prompts = [
    "The capital of France is",
    "In one sentence, what is a transformer?",
    "Write a haiku about GPUs.",
]
inputs = tokenizer(prompts)              # {"input_ids": (3, seq), "attention_mask": (3, seq)}
outputs = model.generate(**inputs, max_new_tokens=64)

for text in tokenizer.batch_decode(outputs):
    print(text)

Backbone only¶

from kerasformers.models.qwen3_5_moe import Qwen35MoeModel

backbone = Qwen35MoeModel.from_weights("qwen3-next-80b-a3b-instruct")
hidden = backbone(inputs)["last_hidden_state"]   # (batch, seq, embed_dim)

Loading from the Hub¶

Any Hub repo with this architecture works via the hf: prefix, including community fine-tunes:

model = Qwen35MoeGenerate.from_weights("hf:Qwen/Qwen3-Next-80B-A3B-Instruct")

Lower memory¶

Larger checkpoints load in bf16 or weight-only quantized. See quantization.md:

model = Qwen35MoeGenerate.from_weights(
    "qwen3-next-80b-a3b-instruct", quantization="int8", low_memory=True, load_dtype="bfloat16"
)