Added check for upper-lower variable bounds

src/andromede/simulation/optimization.py

@@ -15,10 +15,11 @@
 into a mathematical optimization problem.
 """
 
+import math
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from enum import Enum
-from typing import Dict, Iterable, List, Optional, Type
+from typing import Dict, Iterable, List, Optional
 
 import ortools.linear_solver.pywraplp as lp
 
@@ -769,6 +770,11 @@ def _create_variables(self) -> None:
                         solver_var = None
                         solver_var_name = f"{component_prefix}{var_name}{block_suffix}{scenario_suffix}"
 
+                        if math.isclose(lower_bound, upper_bound):
+                            raise ValueError(
+                                f"Upper and lower bounds of variable {solver_var_name} have the same value: {lower_bound}"
+                            )
+
                         if model_var.data_type == ValueType.BOOL:
                             solver_var = self.solver.BoolVar(
                                 solver_var_name,

tests/functional/test_andromede.py

@@ -173,6 +173,14 @@ def test_variable_bound() -> None:
     status = problem.solver.Solve()
     assert status == problem.solver.INFEASIBLE  # Infeasible
 
+    network = create_one_node_network(generator_model)
+    database = create_simple_database(max_generation=0)  # Equal upper and lower bounds
+    with pytest.raises(
+        ValueError,
+        match="Upper and lower bounds of variable G_generation have the same value: 0",
+    ):
+        problem = build_problem(network, database, TimeBlock(1, [0]), 1)
+
 
 def generate_data(
     efficiency: float, horizon: int, scenarios: int

tests/functional/test_performance.py

@@ -139,7 +139,7 @@ def test_large_sum_inside_model_with_sum_operator() -> None:
             float_variable(
                 "var",
                 lower_bound=literal(1),
-                upper_bound=literal(1),
+                upper_bound=literal(2),
                 structure=IndexingStructure(True, False),
             ),
         ],