From 6b839d86bb74e90ba6995095e275974fc63a3b68 Mon Sep 17 00:00:00 2001
From: Robbie Muir <robbie.muir@gmail.com>
Date: Sat, 1 Nov 2025 23:52:55 +0100
Subject: [PATCH 1/2] add linear expression from constant

---
 linopy/expressions.py          | 20 ++++++++++++++++++++
 test/test_linear_expression.py | 15 +++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/linopy/expressions.py b/linopy/expressions.py
index d60c8be5..b480e8a4 100644
--- a/linopy/expressions.py
+++ b/linopy/expressions.py
@@ -1647,6 +1647,26 @@ def process_one(
 
         return merge(exprs, cls=cls) if len(exprs) > 1 else exprs[0]
 
+    @classmethod
+    def from_constant(cls, model: Model, constant: ConstantLike) -> LinearExpression:
+        """
+        Create a linear expression from a constant value or series
+
+        Parameters
+        ----------
+        model : linopy.Model
+            The model to which the constant expression will belong.
+        constant : int/float/array_like
+            The constant value for the linear expression.
+
+        Returns
+        -------
+        linopy.LinearExpression
+            A linear expression representing the constant value.
+        """
+        const_da = as_dataarray(constant)
+        return LinearExpression(const_da, model)
+
 
 class QuadraticExpression(BaseExpression):
     """
diff --git a/test/test_linear_expression.py b/test/test_linear_expression.py
index 2551c203..01c46252 100644
--- a/test/test_linear_expression.py
+++ b/test/test_linear_expression.py
@@ -1123,6 +1123,21 @@ def test_linear_expression_from_tuples_bad_calls(
         LinearExpression.from_tuples(10)
 
 
+def test_linear_expression_from_constant_scalar(m: Model) -> None:
+    expr = LinearExpression.from_constant(model=m, constant=10)
+    assert isinstance(expr, LinearExpression)
+    assert (expr.const == 10).all()
+
+
+def test_linear_expression_from_constant_array(m: Model) -> None:
+    arr = pd.Series(index=pd.Index([0, 1], name="t"), data=[10, 20])
+    expr = LinearExpression.from_constant(model=m, constant=arr)
+    assert isinstance(expr, LinearExpression)
+    assert list(expr.coords.keys())[0] == "t"
+    assert expr.nterm == 0
+    assert (expr.const.values == [10, 20]).all()
+
+
 def test_linear_expression_sanitize(x: Variable, y: Variable, z: Variable) -> None:
     expr = 10 * x + y + z
     assert isinstance(expr.sanitize(), LinearExpression)

From 7626b5975edd2c8e5dc850a8b244ee2e721d784d Mon Sep 17 00:00:00 2001
From: Robbie Muir <robbie.muir@gmail.com>
Date: Sat, 1 Nov 2025 23:54:19 +0100
Subject: [PATCH 2/2] add doc

---
 doc/release_notes.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index 76e5bf24..99847409 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -2,7 +2,7 @@ Release Notes
 =============
 
 .. Upcoming Version
-
+* Add convenience function to create LinearExpression from constant
 
 Version 0.5.8
 --------------