Gemma3 text keras hf checkpoint conversion

tools/checkpoint_conversion/convert_gemma3_checkpoints.py

@@ -10,8 +10,10 @@
 Usage:
 ```shell
 cd tools/checkpoint_conversion
-python convert_gemma3_checkpoints.py --preset gemma3_instruct_1b
-python convert_gemma3_checkpoints.py --preset gemma3_instruct_4b
+python convert_gemma3_checkpoints.py --preset gemma3_instruct_1b \
+    --export_safetensors
+python convert_gemma3_checkpoints.py --preset gemma3_instruct_4b \
+    --export_safetensors
 ```
 """
 
@@ -21,16 +23,209 @@
 # No GPU for conversion, makes memory management easier.
 os.environ["CUDA_VISIBLE_DEVICES"] = "-1"
 
+import json
+import shutil
+
 import keras  # noqa: E402
+import numpy as np
 import tensorflow_datasets as tfds  # noqa: E402
+import torch
+import transformers
 from absl import app  # noqa: E402
 from absl import flags  # noqa: E402
 from checkpoint_conversion_utils import download_gcs_file
 from gemma import gm  # noqa: E402
 from keras import ops  # noqa: E402
+from safetensors.torch import save_file
+from transformers import AutoModelForCausalLM
+from transformers import AutoTokenizer
 
 import keras_hub  # noqa: E402
 
+
+def convert_to_hf_config(keras_config):
+    """Convert Keras Gemma config to Hugging Face GemmaConfig."""
+    hf_config = transformers.Gemma3TextConfig(
+        vocab_size=keras_config.vocabulary_size,
+        num_hidden_layers=keras_config.num_layers,
+        num_attention_heads=keras_config.num_query_heads,
+        num_key_value_heads=keras_config.num_key_value_heads,
+        hidden_size=keras_config.hidden_dim,
+        intermediate_size=keras_config.intermediate_dim,
+        head_dim=keras_config.head_dim,
+        max_position_embeddings=32768,
+    )
+    return hf_config
+
+
+def export_to_hf(backbone, keras_tokenizer, path):
+    """Convert a Keras Gemma model to Hugging Face format and save to path."""
+
+    hf_config = convert_to_hf_config(backbone)
+    weights_dict = {}
+
+    # Helper function to convert bfloat16 weights to torch tensors
+    def to_torch(weight):
+        # Convert bfloat16 to float32 first, then to torch, then to bfloat16
+        if hasattr(weight.dtype, "name") and "bfloat16" in str(weight.dtype):
+            weight = np.array(weight, dtype=np.float32)
+        return torch.from_numpy(weight).to(torch.bfloat16)
+
+    # Token embeddings
+    token_embedding = backbone.get_layer("token_embedding").get_weights()[0]
+    weights_dict["model.embed_tokens.weight"] = to_torch(token_embedding)
+
+    for i in range(backbone.num_layers):
+        block = backbone.get_layer(f"decoder_block_{i}")
+        q_kernel = block.attention.query_dense.get_weights()[0]
+        q_kernel = (
+            torch.from_numpy(np.array(q_kernel, dtype=np.float32))
+            .to(torch.bfloat16)
+            .permute(1, 0, 2)
+            .reshape(backbone.hidden_dim, -1)
+            .T
+        )
+        weights_dict[f"model.layers.{i}.self_attn.q_proj.weight"] = q_kernel
+
+        k_kernel = block.attention.key_dense.get_weights()[0]
+        k_kernel = (
+            torch.from_numpy(np.array(k_kernel, dtype=np.float32))
+            .to(torch.bfloat16)
+            .permute(1, 0, 2)
+            .reshape(backbone.hidden_dim, -1)
+            .T
+        )
+        weights_dict[f"model.layers.{i}.self_attn.k_proj.weight"] = k_kernel
+
+        v_kernel = block.attention.value_dense.get_weights()[0]
+        v_kernel = (
+            torch.from_numpy(np.array(v_kernel, dtype=np.float32))
+            .to(torch.bfloat16)
+            .permute(1, 0, 2)
+            .reshape(backbone.hidden_dim, -1)
+            .T
+        )
+        weights_dict[f"model.layers.{i}.self_attn.v_proj.weight"] = v_kernel
+
+        o_kernel = block.attention.output_dense.get_weights()[0]
+        o_kernel = (
+            torch.from_numpy(np.array(o_kernel, dtype=np.float32))
+            .to(torch.bfloat16)
+            .permute(2, 0, 1)
+            .reshape(backbone.hidden_dim, -1)
+        )
+        weights_dict[f"model.layers.{i}.self_attn.o_proj.weight"] = o_kernel
+
+        q_norm = block.attention.query_norm.get_weights()[0]
+        weights_dict[f"model.layers.{i}.self_attn.q_norm.weight"] = to_torch(
+            q_norm
+        )
+
+        k_norm = block.attention.key_norm.get_weights()[0]
+        weights_dict[f"model.layers.{i}.self_attn.k_norm.weight"] = to_torch(
+            k_norm
+        )
+
+        gate_kernel = block.gating_ffw.get_weights()[0]
+        gate_kernel = (
+            torch.from_numpy(np.array(gate_kernel, dtype=np.float32))
+            .to(torch.bfloat16)
+            .T
+        )
+        weights_dict[f"model.layers.{i}.mlp.gate_proj.weight"] = gate_kernel
+
+        up_kernel = block.gating_ffw_2.get_weights()[0]
+        up_kernel = (
+            torch.from_numpy(np.array(up_kernel, dtype=np.float32))
+            .to(torch.bfloat16)
+            .T
+        )
+        weights_dict[f"model.layers.{i}.mlp.up_proj.weight"] = up_kernel
+
+        down_kernel = block.ffw_linear.get_weights()[0]
+        down_kernel = (
+            torch.from_numpy(np.array(down_kernel, dtype=np.float32))
+            .to(torch.bfloat16)
+            .T
+        )
+        weights_dict[f"model.layers.{i}.mlp.down_proj.weight"] = down_kernel
+
+        input_layer_norm = block.pre_attention_norm.get_weights()[0]
+        weights_dict[f"model.layers.{i}.input_layernorm.weight"] = to_torch(
+            input_layer_norm
+        )
+
+        post_attn_norm = block.post_attention_norm.get_weights()[0]
+        weights_dict[f"model.layers.{i}.post_attention_layernorm.weight"] = (
+            to_torch(post_attn_norm)
+        )
+
+        pre_feedforward_layernorm_weight = block.pre_ffw_norm.get_weights()[0]
+        weights_dict[f"model.layers.{i}.pre_feedforward_layernorm.weight"] = (
+            to_torch(pre_feedforward_layernorm_weight)
+        )
+
+        post_feedforward_layernorm_weight = block.post_ffw_norm.get_weights()[0]
+        weights_dict[f"model.layers.{i}.post_feedforward_layernorm.weight"] = (
+            to_torch(post_feedforward_layernorm_weight)
+        )
+
+    final_norm = backbone.get_layer("final_normalization").get_weights()[0]
+    weights_dict["model.norm.weight"] = to_torch(final_norm)
+    weights_dict["lm_head.weight"] = weights_dict[
+        "model.embed_tokens.weight"
+    ].clone()
+
+    os.makedirs(path, exist_ok=True)
+    with open(os.path.join(path, "config.json"), "w") as f:
+        json.dump(hf_config.to_dict(), f)
+    weights_dict = {k: v.contiguous() for k, v in weights_dict.items()}
+    save_file(weights_dict, os.path.join(path, "model.safetensors"))
+    keras_tokenizer.save_assets(path)
+    vocab_spm = os.path.join(path, "vocabulary.spm")
+    tokenizer_model = os.path.join(path, "tokenizer.model")
+    if os.path.exists(vocab_spm):
+        shutil.move(vocab_spm, tokenizer_model)
+    print("Export complete! Files saved in:", path)
+
+
+def load_hf_model(model_name, device):
+    tokenizer = AutoTokenizer.from_pretrained(model_name)
+    model = AutoModelForCausalLM.from_pretrained(model_name)
+    model.to(device)
+    model.eval()
+    return model, tokenizer
+
+
+def infer(
+    model,
+    tokenizer,
+    prompt,
+    device,
+    max_new_tokens=30,
+    temperature=1.0,
+    top_k=50,
+    top_p=1.0,
+):
+    # Tokenize inpu
+    inputs = tokenizer(prompt, return_tensors="pt").to(device)
+
+    # Generate output
+    with torch.no_grad():
+        outputs = model.generate(
+            **inputs,
+            max_new_tokens=max_new_tokens,
+            temperature=temperature,
+            top_k=top_k,
+            top_p=top_p,
+            do_sample=True,
+        )
+
+    # Decode generated tokens
+    generated_text = tokenizer.decode(outputs[0], skip_special_tokens=False)
+    return generated_text
+
+
 keras.utils.set_random_seed(42)
 
 FLAGS = flags.FLAGS
@@ -126,6 +321,13 @@
     required=True,
 )
 
+flags.DEFINE_bool(
+    "export_safetensors",
+    False,
+    "Export model to Safetensors format (HuggingFace-compatible). \
+        Only for text-only models.",
+)
+
 
 def convert_model(flax_config, text_only):
     vision_encoder = None
@@ -558,6 +760,35 @@ def main(_):
     keras_tokenizer.save_to_preset(preset)
     print(f"🏁 Preset saved to ./{preset}")
 
+    if FLAGS.export_safetensors and text_only:
+        export_dir = f"./{preset}_safetensors_export"
+        print(
+            f"🏃 Exporting to Safetensors (HuggingFace format) at {export_dir}"
+        )
+        export_to_hf(keras_model, keras_tokenizer, export_dir)
+        print(f"🏁 Safetensors export complete: {export_dir}")
+
+        local_hf_model, local_hf_tokenizer = load_hf_model(
+            export_dir, device="cpu"
+        )
+        print("Local Hugging Face model loaded successfully!")
+
+        print(
+            "🔶 Safetensors output:",
+            infer(
+                local_hf_model,
+                local_hf_tokenizer,
+                "What is Keras?",
+                "cpu",
+                max_new_tokens=100,
+            ),
+        )
+    elif FLAGS.export_safetensors:
+        print(
+            "⚠️ Safetensors export is only supported for text-only models. \
+                Skipping export."
+        )
+
 
 if __name__ == "__main__":
     app.run(main)