From b5e8a06a5f22bf5abab4641bd6cc3939720f3a16 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Thu, 9 Apr 2026 23:13:59 +0000
Subject: [PATCH 1/9] feat(bigframes): Support Expression objects in
 create_model options

This change allows the `options` parameter of `bigframes.bigquery._operations.ml.create_model` to accept BigFrames `Expression` objects. These expressions are compiled to SQL scalar expressions and included in the generated `CREATE MODEL` DDL statement.

- Added `bigframes.core.expression.Expression` type support in the `options` dict.
- Updated `create_model_ddl` to handle compiling expressions using `expression_compiler`.
- Added `test_create_model_expression_option` snapshot test to verify the generated "golden SQL".

Co-authored-by: tswast <247555+tswast@users.noreply.github.com>
---
 .../bigframes/bigframes/bigquery/_operations/ml.py |  7 +++++--
 packages/bigframes/bigframes/core/sql/ml.py        | 11 +++++++++--
 .../create_model_expression_option.sql             |  3 +++
 packages/bigframes/tests/unit/core/sql/test_ml.py  | 14 ++++++++++++++
 4 files changed, 31 insertions(+), 4 deletions(-)
 create mode 100644 packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql

diff --git a/packages/bigframes/bigframes/bigquery/_operations/ml.py b/packages/bigframes/bigframes/bigquery/_operations/ml.py
index 04d88c9b6a68..add2dac05fe6 100644
--- a/packages/bigframes/bigframes/bigquery/_operations/ml.py
+++ b/packages/bigframes/bigframes/bigquery/_operations/ml.py
@@ -25,6 +25,7 @@
 import bigframes.dataframe as dataframe
 import bigframes.ml.base
 import bigframes.session
+import bigframes.core.expression as ex
 from bigframes.bigquery._operations import utils
 
 
@@ -50,7 +51,9 @@ def create_model(
     input_schema: Optional[Mapping[str, str]] = None,
     output_schema: Optional[Mapping[str, str]] = None,
     connection_name: Optional[str] = None,
-    options: Optional[Mapping[str, Union[str, int, float, bool, list]]] = None,
+    options: Optional[
+        Mapping[str, Union[str, int, float, bool, list, "ex.Expression"]]
+    ] = None,
     training_data: Optional[Union[pd.DataFrame, dataframe.DataFrame, str]] = None,
     custom_holiday: Optional[Union[pd.DataFrame, dataframe.DataFrame, str]] = None,
     session: Optional[bigframes.session.Session] = None,
@@ -78,7 +81,7 @@ def create_model(
             The OUTPUT clause, which specifies the schema of the output data.
         connection_name (str, optional):
             The connection to use for the model.
-        options (Mapping[str, Union[str, int, float, bool, list]], optional):
+        options (Mapping[str, Union[str, int, float, bool, list, bigframes.core.expression.Expression]], optional):
             The OPTIONS clause, which specifies the model options.
         training_data (Union[bigframes.pandas.DataFrame, str], optional):
             The query or DataFrame to use for training the model.
diff --git a/packages/bigframes/bigframes/core/sql/ml.py b/packages/bigframes/bigframes/core/sql/ml.py
index 9694e19ad30e..4803bcd15049 100644
--- a/packages/bigframes/bigframes/core/sql/ml.py
+++ b/packages/bigframes/bigframes/core/sql/ml.py
@@ -16,7 +16,9 @@
 
 from typing import Any, Dict, List, Mapping, Optional, Union
 
+import bigframes.core.expression as ex
 from bigframes.core.compile.sqlglot import sql as sg_sql
+from bigframes.core.compile.sqlglot.expression_compiler import expression_compiler
 
 
 def create_model_ddl(
@@ -28,7 +30,9 @@ def create_model_ddl(
     input_schema: Optional[Mapping[str, str]] = None,
     output_schema: Optional[Mapping[str, str]] = None,
     connection_name: Optional[str] = None,
-    options: Optional[Mapping[str, Union[str, int, float, bool, list]]] = None,
+    options: Optional[
+        Mapping[str, Union[str, int, float, bool, list, "ex.Expression"]]
+    ] = None,
     training_data: Optional[str] = None,
     custom_holiday: Optional[str] = None,
 ) -> str:
@@ -70,7 +74,10 @@ def create_model_ddl(
     if options:
         rendered_options = []
         for option_name, option_value in options.items():
-            if isinstance(option_value, (list, tuple)):
+            if isinstance(option_value, ex.Expression):
+                sg_expr = expression_compiler.compile_expression(option_value)
+                rendered_val = sg_sql.to_sql(sg_expr)
+            elif isinstance(option_value, (list, tuple)):
                 # Handle list options like model_registry="vertex_ai"
                 # wait, usually options are key=value.
                 # if value is list, it is [val1, val2]
diff --git a/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql b/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
new file mode 100644
index 000000000000..eabfb8a5e962
--- /dev/null
+++ b/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
@@ -0,0 +1,3 @@
+CREATE MODEL `my_model`
+OPTIONS(l2_reg = 0.1, booster_type = 'gbtree')
+AS SELECT * FROM t
diff --git a/packages/bigframes/tests/unit/core/sql/test_ml.py b/packages/bigframes/tests/unit/core/sql/test_ml.py
index bb3b61a949cf..718e4b81ca3b 100644
--- a/packages/bigframes/tests/unit/core/sql/test_ml.py
+++ b/packages/bigframes/tests/unit/core/sql/test_ml.py
@@ -97,6 +97,20 @@ def test_create_model_list_option(snapshot):
     snapshot.assert_match(sql, "create_model_list_option.sql")
 
 
+def test_create_model_expression_option(snapshot):
+    import bigframes.core.expression as ex
+
+    sql = bigframes.core.sql.ml.create_model_ddl(
+        model_name="my_model",
+        options={
+            "l2_reg": ex.ScalarConstantExpression(0.1, None),
+            "booster_type": "gbtree",
+        },
+        training_data="SELECT * FROM t",
+    )
+    snapshot.assert_match(sql, "create_model_expression_option.sql")
+
+
 def test_evaluate_model_basic(snapshot):
     sql = bigframes.core.sql.ml.evaluate(
         model_name="my_project.my_dataset.my_model",

From 7ea8bf595ea68fbbfc578f38eb20856cdec6b48c Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Fri, 10 Apr 2026 03:44:10 +0000
Subject: [PATCH 2/9] feat(bigframes): Support Expression objects in
 create_model options

This change allows the `options` parameter of `bigframes.bigquery._operations.ml.create_model` to accept BigFrames `Expression` objects. These expressions are compiled to SQL scalar expressions and included in the generated `CREATE MODEL` DDL statement.

- Added `bigframes.core.expression.Expression` type support in the `options` dict.
- Updated `create_model_ddl` to handle compiling expressions using `expression_compiler`.
- Added `test_create_model_expression_option` snapshot test to verify the generated "golden SQL", using an expression that calls a function on a literal value (e.g. 0.1 * 10).

Co-authored-by: tswast <247555+tswast@users.noreply.github.com>
---
 .../create_model_expression_option.sql                 |  2 +-
 packages/bigframes/tests/unit/core/sql/test_ml.py      | 10 +++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql b/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
index eabfb8a5e962..e328aab5fbfd 100644
--- a/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
+++ b/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
@@ -1,3 +1,3 @@
 CREATE MODEL `my_model`
-OPTIONS(l2_reg = 0.1, booster_type = 'gbtree')
+OPTIONS(l2_reg = 0.1 * 10, booster_type = 'gbtree')
 AS SELECT * FROM t
diff --git a/packages/bigframes/tests/unit/core/sql/test_ml.py b/packages/bigframes/tests/unit/core/sql/test_ml.py
index 718e4b81ca3b..d46170b771c6 100644
--- a/packages/bigframes/tests/unit/core/sql/test_ml.py
+++ b/packages/bigframes/tests/unit/core/sql/test_ml.py
@@ -99,11 +99,19 @@ def test_create_model_list_option(snapshot):
 
 def test_create_model_expression_option(snapshot):
     import bigframes.core.expression as ex
+    import bigframes.operations.numeric_ops as numeric_ops
+    import bigframes.dtypes as dtypes
+
+    # An expression that calls a function on a literal value
+    # e.g. 0.1 * 10
+    literal_expr = ex.ScalarConstantExpression(0.1, dtypes.FLOAT_DTYPE)
+    multiplier_expr = ex.ScalarConstantExpression(10, dtypes.INT_DTYPE)
+    math_expr = ex.OpExpression(op=numeric_ops.mul_op, inputs=(literal_expr, multiplier_expr))
 
     sql = bigframes.core.sql.ml.create_model_ddl(
         model_name="my_model",
         options={
-            "l2_reg": ex.ScalarConstantExpression(0.1, None),
+            "l2_reg": math_expr,
             "booster_type": "gbtree",
         },
         training_data="SELECT * FROM t",

From f92c089cdca3dc212c7d3d42afb7f716a3acf5cb Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Fri, 10 Apr 2026 04:05:56 +0000
Subject: [PATCH 3/9] feat(bigframes): Support Expression objects in
 create_model options

This change allows the `options` parameter of `bigframes.bigquery._operations.ml.create_model` to accept BigFrames `Expression` objects. These expressions are compiled to SQL scalar expressions and included in the generated `CREATE MODEL` DDL statement.

- Added `bigframes.core.expression.Expression` type support in the `options` dict.
- Updated `create_model_ddl` to handle compiling expressions using `expression_compiler`.
- Added `test_create_model_expression_option` snapshot test to verify the generated "golden SQL", using an expression that calls a function on a literal value (e.g. 0.1 * 10).

Co-authored-by: tswast <247555+tswast@users.noreply.github.com>
---
 packages/bigframes/tests/unit/core/sql/test_ml.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/bigframes/tests/unit/core/sql/test_ml.py b/packages/bigframes/tests/unit/core/sql/test_ml.py
index d46170b771c6..fe7630224ddb 100644
--- a/packages/bigframes/tests/unit/core/sql/test_ml.py
+++ b/packages/bigframes/tests/unit/core/sql/test_ml.py
@@ -106,7 +106,9 @@ def test_create_model_expression_option(snapshot):
     # e.g. 0.1 * 10
     literal_expr = ex.ScalarConstantExpression(0.1, dtypes.FLOAT_DTYPE)
     multiplier_expr = ex.ScalarConstantExpression(10, dtypes.INT_DTYPE)
-    math_expr = ex.OpExpression(op=numeric_ops.mul_op, inputs=(literal_expr, multiplier_expr))
+    math_expr = ex.OpExpression(
+        op=numeric_ops.mul_op, inputs=(literal_expr, multiplier_expr)
+    )
 
     sql = bigframes.core.sql.ml.create_model_ddl(
         model_name="my_model",

From 5d874d0f7b875b881a4bb08f6edd471af0112295 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Fri, 10 Apr 2026 04:43:41 +0000
Subject: [PATCH 4/9] feat(bigframes): Support Expression objects in
 create_model options

This change allows the `options` parameter of `bigframes.bigquery._operations.ml.create_model` to accept BigFrames `Expression` objects. These expressions are compiled to SQL scalar expressions and included in the generated `CREATE MODEL` DDL statement.

- Added `bigframes.core.expression.Expression` type support in the `options` dict.
- Updated `create_model_ddl` to handle compiling expressions using `expression_compiler`.
- Added `test_create_model_expression_option` snapshot test to verify the generated "golden SQL", using an expression that calls a function on a literal value (e.g. 0.1 * 10).
- Moved test imports to the top level to adhere to PEP 8.

Co-authored-by: tswast <247555+tswast@users.noreply.github.com>
---
 packages/bigframes/tests/unit/core/sql/test_ml.py | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/packages/bigframes/tests/unit/core/sql/test_ml.py b/packages/bigframes/tests/unit/core/sql/test_ml.py
index fe7630224ddb..e7d9f628cc2e 100644
--- a/packages/bigframes/tests/unit/core/sql/test_ml.py
+++ b/packages/bigframes/tests/unit/core/sql/test_ml.py
@@ -14,7 +14,10 @@
 
 import pytest
 
+import bigframes.core.expression as ex
 import bigframes.core.sql.ml
+import bigframes.dtypes as dtypes
+import bigframes.operations.numeric_ops as numeric_ops
 
 pytest.importorskip("pytest_snapshot")
 
@@ -98,10 +101,6 @@ def test_create_model_list_option(snapshot):
 
 
 def test_create_model_expression_option(snapshot):
-    import bigframes.core.expression as ex
-    import bigframes.operations.numeric_ops as numeric_ops
-    import bigframes.dtypes as dtypes
-
     # An expression that calls a function on a literal value
     # e.g. 0.1 * 10
     literal_expr = ex.ScalarConstantExpression(0.1, dtypes.FLOAT_DTYPE)

From 58aa74e9d4ada8798850a245b4d2292c47bb223e Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Fri, 10 Apr 2026 21:10:35 +0000
Subject: [PATCH 5/9] feat(bigframes): Support Expression objects in
 create_model options

This change allows the `options` parameter of `bigframes.bigquery._operations.ml.create_model` to accept BigFrames `col.Expression` objects. These expressions are compiled to SQL scalar expressions and included in the generated `CREATE MODEL` DDL statement.

- Added `bigframes.core.col.Expression` type support in the `options` dict.
- Updated `create_model_ddl` to handle compiling expressions using `expression_compiler`.
- Added `test_create_model_expression_option` snapshot test to verify the generated "golden SQL", using an expression that calls a function on a literal value (e.g. 0.1 * 10).
- Moved test imports to the top level to adhere to PEP 8 and ran `ruff format`.

Co-authored-by: tswast <247555+tswast@users.noreply.github.com>
---
 packages/bigframes/bigframes/bigquery/_operations/ml.py | 6 +++---
 packages/bigframes/bigframes/core/sql/ml.py             | 8 ++++----
 packages/bigframes/tests/unit/core/sql/test_ml.py       | 5 +++--
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/packages/bigframes/bigframes/bigquery/_operations/ml.py b/packages/bigframes/bigframes/bigquery/_operations/ml.py
index add2dac05fe6..412b49b888f5 100644
--- a/packages/bigframes/bigframes/bigquery/_operations/ml.py
+++ b/packages/bigframes/bigframes/bigquery/_operations/ml.py
@@ -25,7 +25,7 @@
 import bigframes.dataframe as dataframe
 import bigframes.ml.base
 import bigframes.session
-import bigframes.core.expression as ex
+import bigframes.core.col as col
 from bigframes.bigquery._operations import utils
 
 
@@ -52,7 +52,7 @@ def create_model(
     output_schema: Optional[Mapping[str, str]] = None,
     connection_name: Optional[str] = None,
     options: Optional[
-        Mapping[str, Union[str, int, float, bool, list, "ex.Expression"]]
+        Mapping[str, Union[str, int, float, bool, list, "col.Expression"]]
     ] = None,
     training_data: Optional[Union[pd.DataFrame, dataframe.DataFrame, str]] = None,
     custom_holiday: Optional[Union[pd.DataFrame, dataframe.DataFrame, str]] = None,
@@ -81,7 +81,7 @@ def create_model(
             The OUTPUT clause, which specifies the schema of the output data.
         connection_name (str, optional):
             The connection to use for the model.
-        options (Mapping[str, Union[str, int, float, bool, list, bigframes.core.expression.Expression]], optional):
+        options (Mapping[str, Union[str, int, float, bool, list, bigframes.core.col.Expression]], optional):
             The OPTIONS clause, which specifies the model options.
         training_data (Union[bigframes.pandas.DataFrame, str], optional):
             The query or DataFrame to use for training the model.
diff --git a/packages/bigframes/bigframes/core/sql/ml.py b/packages/bigframes/bigframes/core/sql/ml.py
index 4803bcd15049..8d971e6c3e8d 100644
--- a/packages/bigframes/bigframes/core/sql/ml.py
+++ b/packages/bigframes/bigframes/core/sql/ml.py
@@ -16,7 +16,7 @@
 
 from typing import Any, Dict, List, Mapping, Optional, Union
 
-import bigframes.core.expression as ex
+import bigframes.core.col as col
 from bigframes.core.compile.sqlglot import sql as sg_sql
 from bigframes.core.compile.sqlglot.expression_compiler import expression_compiler
 
@@ -31,7 +31,7 @@ def create_model_ddl(
     output_schema: Optional[Mapping[str, str]] = None,
     connection_name: Optional[str] = None,
     options: Optional[
-        Mapping[str, Union[str, int, float, bool, list, "ex.Expression"]]
+        Mapping[str, Union[str, int, float, bool, list, "col.Expression"]]
     ] = None,
     training_data: Optional[str] = None,
     custom_holiday: Optional[str] = None,
@@ -74,8 +74,8 @@ def create_model_ddl(
     if options:
         rendered_options = []
         for option_name, option_value in options.items():
-            if isinstance(option_value, ex.Expression):
-                sg_expr = expression_compiler.compile_expression(option_value)
+            if isinstance(option_value, col.Expression):
+                sg_expr = expression_compiler.compile_expression(option_value._value)
                 rendered_val = sg_sql.to_sql(sg_expr)
             elif isinstance(option_value, (list, tuple)):
                 # Handle list options like model_registry="vertex_ai"
diff --git a/packages/bigframes/tests/unit/core/sql/test_ml.py b/packages/bigframes/tests/unit/core/sql/test_ml.py
index e7d9f628cc2e..61296638eec2 100644
--- a/packages/bigframes/tests/unit/core/sql/test_ml.py
+++ b/packages/bigframes/tests/unit/core/sql/test_ml.py
@@ -14,6 +14,7 @@
 
 import pytest
 
+import bigframes.core.col as col
 import bigframes.core.expression as ex
 import bigframes.core.sql.ml
 import bigframes.dtypes as dtypes
@@ -105,8 +106,8 @@ def test_create_model_expression_option(snapshot):
     # e.g. 0.1 * 10
     literal_expr = ex.ScalarConstantExpression(0.1, dtypes.FLOAT_DTYPE)
     multiplier_expr = ex.ScalarConstantExpression(10, dtypes.INT_DTYPE)
-    math_expr = ex.OpExpression(
-        op=numeric_ops.mul_op, inputs=(literal_expr, multiplier_expr)
+    math_expr = col.Expression(
+        ex.OpExpression(op=numeric_ops.mul_op, inputs=(literal_expr, multiplier_expr))
     )
 
     sql = bigframes.core.sql.ml.create_model_ddl(

From a95a36a2040d2511510f9bee0eb42309c3a81a17 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20Swe=C3=B1a?= <swast@google.com>
Date: Mon, 13 Apr 2026 21:41:53 +0000
Subject: [PATCH 6/9] feat: add support for `hparam_range` and
 `hparam_candidates` to `bigframes.bigquery.create_model`

---
 .../bigframes/bigframes/bigquery/__init__.py  | 10 ++-
 .../bigquery/_operations/mathematical.py      | 68 +++++++++++++++++++
 .../bigframes/bigquery/_operations/ml.py      |  2 +-
 .../create_model_expression_option.sql        |  3 -
 .../create_model_hparam_tuning.sql            |  3 +
 .../bigframes/tests/unit/core/sql/test_ml.py  | 18 ++---
 packages/bigframes/tests/unit/test_col.py     |  2 +-
 7 files changed, 88 insertions(+), 18 deletions(-)
 delete mode 100644 packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
 create mode 100644 packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_hparam_tuning/create_model_hparam_tuning.sql

diff --git a/packages/bigframes/bigframes/bigquery/__init__.py b/packages/bigframes/bigframes/bigquery/__init__.py
index f08388704585..a31d7dd83f93 100644
--- a/packages/bigframes/bigframes/bigquery/__init__.py
+++ b/packages/bigframes/bigframes/bigquery/__init__.py
@@ -87,7 +87,11 @@
     to_json,
     to_json_string,
 )
-from bigframes.bigquery._operations.mathematical import rand
+from bigframes.bigquery._operations.mathematical import (
+    hparam_candidates,
+    hparam_range,
+    rand,
+)
 from bigframes.bigquery._operations.search import create_vector_index, vector_search
 from bigframes.bigquery._operations.sql import sql_scalar
 from bigframes.bigquery._operations.struct import struct
@@ -130,6 +134,8 @@
     to_json,
     to_json_string,
     # mathematical ops
+    hparam_candidates,
+    hparam_range,
     rand,
     # search ops
     create_vector_index,
@@ -187,6 +193,8 @@
     "to_json",
     "to_json_string",
     # mathematical ops
+    "hparam_candidates",
+    "hparam_range",
     "rand",
     # search ops
     "create_vector_index",
diff --git a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
index 2e8351904775..bed9c307c3df 100644
--- a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
+++ b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
@@ -51,3 +51,71 @@ def rand() -> bigframes.core.col.Expression:
         is_deterministic=False,
     )
     return bigframes.core.col.Expression(bigframes.core.expression.OpExpression(op, ()))
+
+
+def hparam_range(min: float | int, max: float | int) -> bigframes.core.col.Expression:
+    """
+    Defines the minimum and maximum bounds of the search space of continuous
+    values for a hyperparameter.
+
+    **Examples:**
+
+        >>> import bigframes.pandas as bpd
+        >>> import bigframes.bigquery as bbq
+        >>> # Specify a range of values for a hyperparameter.
+        >>> learn_rate = bbq.hparam_range(0.0001, 1.0)
+
+    Args:
+        min (float or int):
+            The minimum bound of the search space.
+        max (float or int):
+            The maximum bound of the search space.
+
+    Returns:
+        bigframes.pandas.api.typing.Expression:
+            An expression that can be used in model options.
+    """
+    min_expr = bigframes.core.expression.const(min)
+    max_expr = bigframes.core.expression.const(max)
+
+    op = ops.SqlScalarOp(
+        _output_type=dtypes.FLOAT_DTYPE,
+        sql_template="HPARAM_RANGE({0}, {1})",
+        is_deterministic=True,
+    )
+    return bigframes.core.col.Expression(
+        bigframes.core.expression.OpExpression(op, (min_expr, max_expr))
+    )
+
+
+def hparam_candidates(
+    candidates: list[float | int | str],
+) -> bigframes.core.col.Expression:
+    """
+    Specifies the set of discrete values for the hyperparameter.
+
+    **Examples:**
+
+        >>> import bigframes.pandas as bpd
+        >>> import bigframes.bigquery as bbq
+        >>> # Specify a set of values for a hyperparameter.
+        >>> optimizer = bbq.hparam_candidates(['ADAGRAD', 'SGD', 'FTRL'])
+
+    Args:
+        candidates (list):
+            The set of discrete values for the hyperparameter.
+
+    Returns:
+        bigframes.pandas.api.typing.Expression:
+            An expression that can be used in model options.
+    """
+    candidates_expr = bigframes.core.expression.const(candidates)
+
+    op = ops.SqlScalarOp(
+        _output_type=dtypes.STRING_DTYPE,
+        sql_template="HPARAM_CANDIDATES({0})",
+        is_deterministic=True,
+    )
+    return bigframes.core.col.Expression(
+        bigframes.core.expression.OpExpression(op, (candidates_expr,))
+    )
diff --git a/packages/bigframes/bigframes/bigquery/_operations/ml.py b/packages/bigframes/bigframes/bigquery/_operations/ml.py
index 412b49b888f5..c6ef1f8bb7a7 100644
--- a/packages/bigframes/bigframes/bigquery/_operations/ml.py
+++ b/packages/bigframes/bigframes/bigquery/_operations/ml.py
@@ -20,12 +20,12 @@
 import google.cloud.bigquery
 import pandas as pd
 
+import bigframes.core.col as col
 import bigframes.core.logging.log_adapter as log_adapter
 import bigframes.core.sql.ml
 import bigframes.dataframe as dataframe
 import bigframes.ml.base
 import bigframes.session
-import bigframes.core.col as col
 from bigframes.bigquery._operations import utils
 
 
diff --git a/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql b/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
deleted file mode 100644
index e328aab5fbfd..000000000000
--- a/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_expression_option/create_model_expression_option.sql
+++ /dev/null
@@ -1,3 +0,0 @@
-CREATE MODEL `my_model`
-OPTIONS(l2_reg = 0.1 * 10, booster_type = 'gbtree')
-AS SELECT * FROM t
diff --git a/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_hparam_tuning/create_model_hparam_tuning.sql b/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_hparam_tuning/create_model_hparam_tuning.sql
new file mode 100644
index 000000000000..c7ed32e54fc8
--- /dev/null
+++ b/packages/bigframes/tests/unit/core/sql/snapshots/test_ml/test_create_model_hparam_tuning/create_model_hparam_tuning.sql
@@ -0,0 +1,3 @@
+CREATE MODEL `my_model`
+OPTIONS(model_type = 'LINEAR_REG', learn_rate = HPARAM_RANGE(0.0001, 1.0), optimizer = HPARAM_CANDIDATES(['ADAGRAD', 'SGD']))
+AS SELECT * FROM t
diff --git a/packages/bigframes/tests/unit/core/sql/test_ml.py b/packages/bigframes/tests/unit/core/sql/test_ml.py
index 61296638eec2..d2f789fc6309 100644
--- a/packages/bigframes/tests/unit/core/sql/test_ml.py
+++ b/packages/bigframes/tests/unit/core/sql/test_ml.py
@@ -14,6 +14,7 @@
 
 import pytest
 
+import bigframes.bigquery as bbq
 import bigframes.core.col as col
 import bigframes.core.expression as ex
 import bigframes.core.sql.ml
@@ -101,24 +102,17 @@ def test_create_model_list_option(snapshot):
     snapshot.assert_match(sql, "create_model_list_option.sql")
 
 
-def test_create_model_expression_option(snapshot):
-    # An expression that calls a function on a literal value
-    # e.g. 0.1 * 10
-    literal_expr = ex.ScalarConstantExpression(0.1, dtypes.FLOAT_DTYPE)
-    multiplier_expr = ex.ScalarConstantExpression(10, dtypes.INT_DTYPE)
-    math_expr = col.Expression(
-        ex.OpExpression(op=numeric_ops.mul_op, inputs=(literal_expr, multiplier_expr))
-    )
-
+def test_create_model_hparam_tuning(snapshot):
     sql = bigframes.core.sql.ml.create_model_ddl(
         model_name="my_model",
         options={
-            "l2_reg": math_expr,
-            "booster_type": "gbtree",
+            "model_type": "LINEAR_REG",
+            "learn_rate": bbq.hparam_range(0.0001, 1.0),
+            "optimizer": bbq.hparam_candidates(["ADAGRAD", "SGD"]),
         },
         training_data="SELECT * FROM t",
     )
-    snapshot.assert_match(sql, "create_model_expression_option.sql")
+    snapshot.assert_match(sql, "create_model_hparam_tuning.sql")
 
 
 def test_evaluate_model_basic(snapshot):
diff --git a/packages/bigframes/tests/unit/test_col.py b/packages/bigframes/tests/unit/test_col.py
index cf9aa5c4b86a..9f5bbca5d9bc 100644
--- a/packages/bigframes/tests/unit/test_col.py
+++ b/packages/bigframes/tests/unit/test_col.py
@@ -16,13 +16,13 @@
 import pathlib
 from typing import Generator
 
+import numpy as np
 import pandas as pd
 import pytest
 
 import bigframes
 import bigframes.pandas as bpd
 from bigframes.testing.utils import assert_frame_equal, convert_pandas_dtypes
-import numpy as np
 
 pytest.importorskip("polars")
 pytest.importorskip("pandas", minversion="3.0.0")

From 1ee0f93baa49405695d246d16632ae1c75c651dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20Swe=C3=B1a=20=28Swast=29?= <swast@google.com>
Date: Mon, 13 Apr 2026 16:48:11 -0500
Subject: [PATCH 7/9] Update
 packages/bigframes/bigframes/bigquery/_operations/mathematical.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 .../bigframes/bigframes/bigquery/_operations/mathematical.py    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
index bed9c307c3df..2c86ccc9991e 100644
--- a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
+++ b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
@@ -53,7 +53,7 @@ def rand() -> bigframes.core.col.Expression:
     return bigframes.core.col.Expression(bigframes.core.expression.OpExpression(op, ()))
 
 
-def hparam_range(min: float | int, max: float | int) -> bigframes.core.col.Expression:
+def hparam_range(min: float, max: float) -> bigframes.core.col.Expression:
     """
     Defines the minimum and maximum bounds of the search space of continuous
     values for a hyperparameter.

From 30506fa1609cab52da09fe5cc9f8e08e010a5a8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20Swe=C3=B1a=20=28Swast=29?= <swast@google.com>
Date: Mon, 13 Apr 2026 16:48:45 -0500
Subject: [PATCH 8/9] Apply suggestions from code review

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
---
 .../bigframes/bigframes/bigquery/_operations/mathematical.py    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
index 2c86ccc9991e..ed2ac120b175 100644
--- a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
+++ b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
@@ -89,7 +89,7 @@ def hparam_range(min: float, max: float) -> bigframes.core.col.Expression:
 
 
 def hparam_candidates(
-    candidates: list[float | int | str],
+    candidates: list[float | str],
 ) -> bigframes.core.col.Expression:
     """
     Specifies the set of discrete values for the hyperparameter.

From 32e7040916024ed3cd33dcb275a341e879645adf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20Swe=C3=B1a?= <swast@google.com>
Date: Tue, 28 Apr 2026 19:49:36 +0000
Subject: [PATCH 9/9] chore: mypy fixesx

---
 .../bigframes/bigquery/_operations/mathematical.py        | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
index ed2ac120b175..476d012bea4d 100644
--- a/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
+++ b/packages/bigframes/bigframes/bigquery/_operations/mathematical.py
@@ -14,6 +14,8 @@
 
 from __future__ import annotations
 
+from typing import Sequence
+
 import bigframes.core.col
 import bigframes.core.expression
 from bigframes import dtypes
@@ -89,7 +91,7 @@ def hparam_range(min: float, max: float) -> bigframes.core.col.Expression:
 
 
 def hparam_candidates(
-    candidates: list[float | str],
+    candidates: Sequence[float | str],
 ) -> bigframes.core.col.Expression:
     """
     Specifies the set of discrete values for the hyperparameter.
@@ -102,14 +104,14 @@ def hparam_candidates(
         >>> optimizer = bbq.hparam_candidates(['ADAGRAD', 'SGD', 'FTRL'])
 
     Args:
-        candidates (list):
+        candidates (Sequence[float | str]):
             The set of discrete values for the hyperparameter.
 
     Returns:
         bigframes.pandas.api.typing.Expression:
             An expression that can be used in model options.
     """
-    candidates_expr = bigframes.core.expression.const(candidates)
+    candidates_expr = bigframes.core.expression.const(tuple(candidates))
 
     op = ops.SqlScalarOp(
         _output_type=dtypes.STRING_DTYPE,