[quantization] Support Vision Encoder wrapper for Gemma4

[Torrero]

Summary

Introduce a PTQ wrapper (QuantGemma4VisionEncoder) for the Hugging Face Gemma4VisionEncoder module, enabling post-training quantization of the Gemma4 vision tower with both dynamic evaluation and static torch.export paths.

Changes

tico/quantization/wrapq/wrappers/gemma4/quant_vision_encoder.py

• QuantGemma4VisionEncoder registered against Gemma4VisionEncoder via @try_register
• Dynamic forward path (forward): computes RoPE position embeddings via precomputed lookup tables (cos_table/sin_table) and bidirectional attention masks from pixel_position_ids — used during calibration and accuracy evaluation.
• Static export path (forward_export): reads precomputed position_embeddings and attention_mask from registered buffers, avoiding any dynamic shape-dependent computation — safe for torch.export tracing
• Precomputes RoPE sin/cos lookup tables for all position IDs at __init__, replacing the dynamic matmul+cos/sin with a simple gather
• Observers on input activations, attention mask, position embeddings (cos/sin), and encoder output

Smoke Tests

Command:

python -m tico.quantization.examples.inspect   \
--config tico/quantization/examples/configs/wrapper_smoke.yaml     \
--mode wrapper-smoke     \
--case gemma4_vision_encoder     \
--export circle     \
--output-dir ./out/wrapper_smoke

[QuantCheck] WARNING: 45 nodes without qparam detected (see logs).
┌───────────── Wrapper Smoke Summary ─────────────
│ Case             : gemma4_vision_encoder
│ Status           : PASS
│ Mean |diff|      : 0.079886
│ Max |diff|       : 0.503346
│ PEIR             : 0.056661
│ Shape match      : True
│ Quant finite     : True
└─────────────────────────────────────────────────
Artifacts:
  - circle: out/wrapper_smoke/gemma4_vision_encoder.q.circle
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    └┬──────────┬──────────┬─────────┬──────────┬┘
   -4.9       -2.4        0.1       2.7       5.2 

UnitTests

Command:

python -m pytest test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py -x -v 

27 tests passed. Output

============================================================================================================= test session starts =============================================================================================================
platform linux -- Python 3.10.12, pytest-9.1.1, pluggy-1.6.0 -- /home/emaltsev/SAMSUNG/llm_quantization/.gemma_venv/bin/python
cachedir: .pytest_cache
rootdir: /home/emaltsev/SAMSUNG/llm_quantization/TICO_my/TICO
configfile: pyproject.toml
plugins: anyio-4.13.0
collected 27 items                                                                                                                                                                                                                            

test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_as_export_module_precomputes_buffers_on_wrapper PASSED                                                                         [  3%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_as_export_module_rejects_mismatched_pixel_position_ids PASSED                                                                  [  7%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_as_export_module_requires_quant_mode PASSED                                                                                    [ 11%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_as_export_module_returns_adapter PASSED                                                                                        [ 14%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_as_export_module_with_padding_produces_valid_output PASSED                                                                     [ 18%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_as_export_module_without_pixel_position_ids_uses_templates PASSED                                                              [ 22%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_attention_mask_is_fake_quantized_in_quant_mode PASSED                                                                          [ 25%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_attention_mask_is_observed_in_calib_mode PASSED                                                                                [ 29%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_dtype_override PASSED                                                                                                          [ 33%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_dynamic_forward_with_padding_produces_valid_output PASSED                                                                      [ 37%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_forward_export_matches_forward PASSED                                                                                          [ 40%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_forward_export_requires_precomputed_buffers PASSED                                                                             [ 44%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_gather_position_embeddings_matches_hf_rotary PASSED                                                                            [ 48%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_gather_position_embeddings_with_padding PASSED                                                                                 [ 51%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_input_is_observed_in_calib_mode PASSED                                                                                         [ 55%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_make_bidirectional_mask_fill_value PASSED                                                                                      [ 59%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_make_bidirectional_mask_no_padding PASSED                                                                                      [ 62%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_make_bidirectional_mask_with_padding PASSED                                                                                    [ 66%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_mode_transitions PASSED                                                                                                        [ 70%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_no_quant_forward_matches_fp PASSED                                                                                             [ 74%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_no_quant_output_shape PASSED                                                                                                   [ 77%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_observers_are_collected PASSED                                                                                                 [ 81%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_output_is_fake_quantized_in_quant_mode PASSED                                                                                  [ 85%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_position_cos_sin_are_observed_in_calib_mode PASSED                                                                             [ 88%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_position_embeddings_are_fake_quantized_in_quant_mode PASSED                                                                    [ 92%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_quant_mode_output_is_finite PASSED                                                                                             [ 96%]
test/quantization/wrapq/wrappers/gemma4/test_quant_vision_encoder.py::TestQuantGemma4VisionEncoder::test_unsupported_export_mode_raises PASSED                                                                                          [100%]

============================================================================================================= 27 passed in 5.53s ==============================================================================================================

TICO-DCO-1.0-Signed-off-by: Evgenii Maltsev e.maltsev@samsung.com

[dvsav]

Could you please clarify the cause of [QuantCheck] WARNING: 45 nodes without qparam detected (see logs). in the smoke test?
The exact culprit can be traced down by adding debug prints to tico/quantization/wrapq/utils/check_missing_qparam.py (print node.stack_trace of nodes lacking qparam).

[dvsav]

Would you consider adding test/quantization/wrapq/wrappers/gemma4/test_quantize_vision_encoder.py?