[Models] Improve iteration over layers (#19497)

Signed-off-by: Lukas Geiger <lukas.geiger94@gmail.com>

vllm/model_executor/models/gemma3.py

@@ -16,6 +16,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -398,7 +399,7 @@ class Gemma3Model(nn.Module):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,

vllm/model_executor/models/glm4_moe.py

@@ -24,6 +24,7 @@
 """Inference-only GLM-4.5 model compatible with HuggingFace weights."""
 import typing
 from collections.abc import Callable, Iterable
+from itertools import islice
 from typing import Any, Optional, Union
 
 import torch
@@ -440,8 +441,7 @@ class Glm4MoeModel(nn.Module):
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
 
-        for i in range(self.start_layer, self.end_layer):
-            layer = self.layers[i]
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(positions, hidden_states, residual)
 
         if not get_pp_group().is_last_rank:

vllm/model_executor/models/gpt2.py

@@ -20,6 +20,7 @@
 # limitations under the License.
 """Inference-only GPT-2 model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -228,7 +229,7 @@ class GPT2Model(nn.Module):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
 
-        for layer in self.h[self.start_layer:self.end_layer]:
+        for layer in islice(self.h, self.start_layer, self.end_layer):
             hidden_states = layer(hidden_states)
 
         if not get_pp_group().is_last_rank:

vllm/model_executor/models/gpt_bigcode.py

@@ -21,6 +21,7 @@
 # limitations under the License.
 """Inference-only GPTBigCode model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -246,7 +247,7 @@ class GPTBigCodeModel(nn.Module):
         else:
             hidden_states = intermediate_tensors["hidden_states"]
 
-        for layer in self.h[self.start_layer:self.end_layer]:
+        for layer in islice(self.h, self.start_layer, self.end_layer):
             hidden_states = layer(hidden_states)
 
         if not get_pp_group().is_last_rank:

vllm/model_executor/models/gpt_j.py

@@ -19,6 +19,7 @@
 # limitations under the License.
 """Inference-only GPT-J model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -223,7 +224,7 @@ class GPTJModel(nn.Module):
                 hidden_states = self.get_input_embeddings(input_ids)
         else:
             hidden_states = intermediate_tensors["hidden_states"]
-        for layer in self.h[self.start_layer:self.end_layer]:
+        for layer in islice(self.h, self.start_layer, self.end_layer):
             hidden_states = layer(position_ids, hidden_states)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({"hidden_states": hidden_states})

vllm/model_executor/models/gpt_neox.py

@@ -19,6 +19,7 @@
 # limitations under the License.
 """Inference-only GPT-NeoX model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -235,7 +236,7 @@ class GPTNeoXModel(nn.Module):
                 hidden_states = self.get_input_embeddings(input_ids)
         else:
             hidden_states = intermediate_tensors["hidden_states"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states = layer(position_ids, hidden_states)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({"hidden_states": hidden_states})

vllm/model_executor/models/granite.py

@@ -24,6 +24,7 @@
 # limitations under the License.
 """Inference-only IBM Granite model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Any, Optional, Union
 
 import torch
@@ -316,7 +317,7 @@ class GraniteModel(nn.Module):
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
 
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states = layer(positions, hidden_states)
 
         if not get_pp_group().is_last_rank:

vllm/model_executor/models/granitemoe.py

@@ -24,6 +24,7 @@
 # limitations under the License.
 """Inference-only GraniteMoe model."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Any, Optional
 
 import torch
@@ -303,7 +304,7 @@ class GraniteMoeModel(nn.Module):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states = layer(positions, hidden_states)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({

vllm/model_executor/models/granitemoehybrid.py

@@ -397,8 +397,7 @@ class GraniteMoeHybridModel(nn.Module):
             residual = intermediate_tensors["residual"]
 
         num_attn = 0
-        for i in range(len(self.layers)):
-            layer = self.layers[i]
+        for i, layer in enumerate(self.layers):
             if isinstance(layer, GraniteMoeHybridAttentionDecoderLayer):
                 num_attn += 1
 

vllm/model_executor/models/granitemoeshared.py

@@ -6,6 +6,7 @@ The architecture is the same as granitemoe but with the addition of shared
 experts.
 """
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional
 
 import torch
@@ -200,8 +201,7 @@ class GraniteMoeSharedModel(nn.Module):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for i in range(self.start_layer, self.end_layer):
-            layer = self.layers[i]
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states = layer(positions, hidden_states)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({

vllm/model_executor/models/grok1.py

@@ -23,6 +23,7 @@
 # limitations under the License.
 """Inference-only Grok1 model."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -347,8 +348,7 @@ class Grok1Model(nn.Module):
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
 
-        for i in range(self.start_layer, self.end_layer):
-            layer = self.layers[i]
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(positions, hidden_states, residual)
 
         if not get_pp_group().is_last_rank:

vllm/model_executor/models/internlm2.py

@@ -3,6 +3,7 @@
 
 from collections.abc import Iterable
 from functools import partial
+from itertools import islice
 from typing import Any, Optional, Union
 
 import torch
@@ -297,7 +298,7 @@ class InternLM2Model(nn.Module):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(positions, hidden_states, residual)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({

vllm/model_executor/models/internlm2_ve.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -123,7 +124,7 @@ class InternLM2VEModel(InternLM2Model):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,

vllm/model_executor/models/jais.py

@@ -23,6 +23,7 @@
 
 import math
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -276,7 +277,7 @@ class JAISModel(nn.Module):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
 
-        for layer in self.h[self.start_layer:self.end_layer]:
+        for layer in islice(self.h, self.start_layer, self.end_layer):
             hidden_states = layer(hidden_states)
 
         if not get_pp_group().is_last_rank:

vllm/model_executor/models/jamba.py

@@ -2,6 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Inference-only Jamba model."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional
 
 import torch
@@ -350,7 +351,7 @@ class JambaModel(nn.Module):
 
         kv_cache_index = 0
         mamba_cache_index = 0
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             layer_mamba_cache_params = None
             if isinstance(layer, JambaAttentionDecoderLayer):
                 kv_cache_index += 1

vllm/model_executor/models/lfm2.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 from collections.abc import Iterable
+from itertools import islice
 from typing import Any, Optional
 
 import torch
@@ -374,7 +375,7 @@ class Lfm2Model(nn.Module):
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
 
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions=positions,
                 hidden_states=hidden_states,

vllm/model_executor/models/llama.py

@@ -24,6 +24,7 @@
 # limitations under the License.
 """Inference-only LLaMA model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Any, Optional, Union
 
 import torch
@@ -383,7 +384,7 @@ class LlamaModel(nn.Module):
 
         aux_hidden_states = []
         for idx, layer in enumerate(
-                self.layers[self.start_layer:self.end_layer]):
+                islice(self.layers, self.start_layer, self.end_layer)):
             if idx in self.aux_hidden_state_layers:
                 aux_hidden_states.append(hidden_states + residual)
             hidden_states, residual = layer(positions, hidden_states, residual)

vllm/model_executor/models/mamba2.py

@@ -164,9 +164,7 @@ class Mamba2Model(nn.Module):
             # v1 get mamba2_metadata from forward_context
             mamba2_metadata = None
 
-        for i in range(len(self.layers)):
-            layer = self.layers[i]
-
+        for i, layer in enumerate(self.layers):
             hidden_states, residual = layer(
                 positions=positions,
                 hidden_states=hidden_states,

vllm/model_executor/models/mimo.py

@@ -26,6 +26,7 @@
 # limitations under the License.
 """Inference-only MiMo model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -74,7 +75,7 @@ class MiMoModel(Qwen2Model):
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,

vllm/model_executor/models/minicpm.py

@@ -25,6 +25,7 @@
 """Inference-only MiniCPM model compatible with HuggingFace weights."""
 import math
 from collections.abc import Iterable
+from itertools import islice
 from typing import Any, Optional, Union
 
 import torch
@@ -414,7 +415,7 @@ class MiniCPMModel(nn.Module):
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
 
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,