[quantization] Extract qscheme helpers to utils

test/quantization/config/test_builders.py

@@ -15,7 +15,6 @@
 import unittest
 
 from tico.quantization.config.builders import (
-    _auto_qscheme_for,
     _build_llama_layer_overrides,
     _build_llama_overrides,
     _build_norm_override,
@@ -25,6 +24,7 @@
     build_llm_ptq_config,
 )
 from tico.quantization.config.ptq import PTQConfig
+from tico.quantization.config.utils import auto_qscheme_for
 from tico.quantization.wrapq.dtypes import DType
 from tico.quantization.wrapq.observers.ema import EMAObserver
 from tico.quantization.wrapq.qscheme import QScheme
@@ -33,19 +33,19 @@
 class TestBuilderHelpers(unittest.TestCase):
     def test_auto_qscheme_for_unsigned_activation(self):
         self.assertEqual(
-            _auto_qscheme_for(DType.uint(8), "act_in"),
+            auto_qscheme_for(DType.uint(8), "act_in"),
             QScheme.PER_TENSOR_ASYMM,
         )
 
     def test_auto_qscheme_for_unsigned_weight(self):
         self.assertEqual(
-            _auto_qscheme_for(DType.uint(8), "weight"),
+            auto_qscheme_for(DType.uint(8), "weight"),
             QScheme.PER_CHANNEL_ASYMM,
         )
 
     def test_auto_qscheme_for_signed_dtype(self):
         self.assertEqual(
-            _auto_qscheme_for(DType.int(8), "weight"),
+            auto_qscheme_for(DType.int(8), "weight"),
             QScheme.PER_TENSOR_SYMM,
         )
 

test/quantization/config/test_utils.py

@@ -0,0 +1,64 @@
+# Copyright (c) 2026 Samsung Electronics Co., Ltd. All Rights Reserved
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+from tico.quantization.config.utils import auto_qscheme_for, dtype_is_unsigned
+from tico.quantization.wrapq.dtypes import DType
+from tico.quantization.wrapq.qscheme import QScheme
+
+
+class TestUtils(unittest.TestCase):
+    def test_dtype_is_unsigned_true(self):
+        self.assertTrue(dtype_is_unsigned(DType.uint(8)))
+        self.assertTrue(dtype_is_unsigned(DType.uint(4)))
+
+    def test_dtype_is_unsigned_false(self):
+        self.assertFalse(dtype_is_unsigned(DType.int(8)))
+        self.assertFalse(dtype_is_unsigned(DType.int(16)))
+
+    def test_auto_qscheme_for_unsigned_activation(self):
+        self.assertEqual(
+            auto_qscheme_for(DType.uint(8), "act_in"),
+            QScheme.PER_TENSOR_ASYMM,
+        )
+
+    def test_auto_qscheme_for_unsigned_weight(self):
+        self.assertEqual(
+            auto_qscheme_for(DType.uint(8), "weight"),
+            QScheme.PER_CHANNEL_ASYMM,
+        )
+
+    def test_auto_qscheme_for_signed_dtype(self):
+        self.assertEqual(
+            auto_qscheme_for(DType.int(8), "act_in"),
+            QScheme.PER_TENSOR_SYMM,
+        )
+        self.assertEqual(
+            auto_qscheme_for(DType.int(16), "weight"),
+            QScheme.PER_TENSOR_SYMM,
+        )
+
+    def test_auto_qscheme_for_default_obs_name(self):
+        """
+        When obs_name is None, it should behave like activation.
+        """
+        self.assertEqual(
+            auto_qscheme_for(DType.uint(8), None),
+            QScheme.PER_TENSOR_ASYMM,
+        )
+        self.assertEqual(
+            auto_qscheme_for(DType.int(8), None),
+            QScheme.PER_TENSOR_SYMM,
+        )

tico/quantization/config/builders.py

@@ -16,28 +16,13 @@
 from typing import Any, Dict, Optional, Tuple, Type
 
 from tico.quantization.config.ptq import PTQConfig, WrapperVariant
+from tico.quantization.config.utils import auto_qscheme_for
 from tico.quantization.wrapq.dtypes import DType
 from tico.quantization.wrapq.observers.base import ObserverBase
 from tico.quantization.wrapq.observers.minmax import MinMaxObserver
 from tico.quantization.wrapq.qscheme import QScheme
 
 
-def _auto_qscheme_for(dtype: DType, obs_name: Optional[str] = None) -> QScheme:
-    """
-    Choose the default qscheme associated with a dtype and observer name.
-
-    Default policy:
-      - signed dtype   -> symmetric per-tensor
-      - unsigned dtype -> asymmetric per-tensor
-      - unsigned weight -> asymmetric per-channel
-    """
-    if not dtype.signed:
-        if obs_name == "weight":
-            return QScheme.PER_CHANNEL_ASYMM
-        return QScheme.PER_TENSOR_ASYMM
-    return QScheme.PER_TENSOR_SYMM
-
-
 def _weight_dtype_from_bits(bits: int) -> DType:
     """
     Convert a commonly used bit-width into a corresponding quantized dtype.
@@ -159,7 +144,7 @@ def _build_weight_override(weight_dtype: Optional[DType]) -> Dict[str, Any]:
     return {
         "weight": {
             "dtype": weight_dtype,
-            "qscheme": _auto_qscheme_for(weight_dtype, "weight"),
+            "qscheme": auto_qscheme_for(weight_dtype, "weight"),
         }
     }
 
@@ -189,12 +174,12 @@ def _build_norm_override(
 
     if norm_dtype is not None:
         override["dtype"] = norm_dtype
-        override["qscheme"] = _auto_qscheme_for(norm_dtype)
+        override["qscheme"] = auto_qscheme_for(norm_dtype)
 
     if norm_weight_dtype is not None:
         override["weight"] = {
             "dtype": norm_weight_dtype,
-            "qscheme": _auto_qscheme_for(norm_weight_dtype, "weight"),
+            "qscheme": auto_qscheme_for(norm_weight_dtype, "weight"),
         }
 
     return override

tico/quantization/config/ptq.py

@@ -17,6 +17,7 @@
 from typing import Any, Dict, Iterable, Literal, Mapping, MutableMapping, Optional, Type
 
 from tico.quantization.config.base import BaseConfig
+from tico.quantization.config.utils import auto_qscheme_for, dtype_is_unsigned
 from tico.quantization.wrapq.dtypes import DType
 from tico.quantization.wrapq.observers.base import ObserverBase
 from tico.quantization.wrapq.observers.minmax import MinMaxObserver
@@ -25,29 +26,6 @@
 WrapperVariant = Literal["common", "prefill", "decode"]
 
 
-def _dtype_is_unsigned(dtype: DType) -> bool:
-    """
-    Return True when the dtype is unsigned.
-    """
-    return not dtype.signed
-
-
-def _auto_qscheme_for(dtype: DType, obs_name: Optional[str] = None) -> QScheme:
-    """
-    Choose a default qscheme from the effective dtype and observer name.
-
-    Default policy:
-      - signed dtype    -> symmetric per-tensor
-      - unsigned dtype  -> asymmetric per-tensor
-      - unsigned weight -> asymmetric per-channel
-    """
-    if _dtype_is_unsigned(dtype):
-        if obs_name == "weight":
-            return QScheme.PER_CHANNEL_ASYMM
-        return QScheme.PER_TENSOR_ASYMM
-    return QScheme.PER_TENSOR_SYMM
-
-
 def _resolve_qscheme(
     *,
     dtype: DType,
@@ -62,9 +40,9 @@ def _resolve_qscheme(
       1. If `qscheme` is None, infer it from `dtype` and `obs_name`.
       2. If the caller explicitly provides an incompatible pair, raise.
     """
-    resolved_qscheme = qscheme or _auto_qscheme_for(dtype, obs_name)
+    resolved_qscheme = qscheme or auto_qscheme_for(dtype, obs_name)
 
-    if _dtype_is_unsigned(dtype) and resolved_qscheme.is_symmetric():
+    if dtype_is_unsigned(dtype) and resolved_qscheme.is_symmetric():
         raise ValueError(
             f"Invalid quantization config at {context}: unsigned dtype "
             f"{dtype!r} cannot be paired with symmetric qscheme "

tico/quantization/config/utils.py

@@ -0,0 +1,41 @@
+# Copyright (c) 2026 Samsung Electronics Co., Ltd. All Rights Reserved
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import Optional
+
+from tico.quantization.wrapq.dtypes import DType
+from tico.quantization.wrapq.qscheme import QScheme
+
+
+def dtype_is_unsigned(dtype: DType) -> bool:
+    """
+    Return True when the dtype is unsigned.
+    """
+    return not dtype.signed
+
+
+def auto_qscheme_for(dtype: DType, obs_name: Optional[str] = None) -> QScheme:
+    """
+    Choose the default qscheme associated with a dtype and observer name.
+
+    Default policy:
+      - signed dtype    -> symmetric per-tensor
+      - unsigned dtype  -> asymmetric per-tensor
+      - unsigned weight -> asymmetric per-channel
+    """
+    if dtype_is_unsigned(dtype):
+        if obs_name == "weight":
+            return QScheme.PER_CHANNEL_ASYMM
+        return QScheme.PER_TENSOR_ASYMM
+    return QScheme.PER_TENSOR_SYMM