Better fix_variable interface

Author: alexandrutomescu

examples/cycles_demo.py

@@ -27,7 +27,8 @@ def test_min_flow_decomp(filename: str):
         subset_constraints=graph.graph["constraints"], # try with and without
         optimization_options={
             "optimize_with_safe_sequences": True, # set to false to deactivate the safe sequences optimization
-            "optimize_with_safe_sequences_allow_geq_constraints": False,
+            "optimize_with_safe_sequences_allow_geq_constraints": True,
+            "optimize_with_safe_sequences_fix_via_bounds": False,
         },
         solver_options={
             "external_solver": "gurobi", # we can try also "highs" at some point
@@ -148,10 +149,10 @@ def process_solution(model):
     print("avg_size_of_non_trivial_SCC:", solve_statistics['avg_size_of_non_trivial_SCC']) # size = number of edges
 
 def main():
-    test_min_flow_decomp(filename = "tests/cyclic_graphs/gt3.kmer15.(130000.132000).V23.E32.cyc100.graph")
-    # test_min_flow_decomp(filename = "tests/cyclic_graphs/gt5.kmer27.(655000.660000).V18.E27.mincyc4.e0.75.graph")
-    test_least_abs_errors(filename = "tests/cyclic_graphs/gt5.kmer27.(655000.660000).V18.E27.mincyc4.e0.75.graph")
-    test_min_path_error(filename = "tests/cyclic_graphs/gt5.kmer27.(655000.660000).V18.E27.mincyc4.e0.75.graph")
+    # test_min_flow_decomp(filename = "tests/cyclic_graphs/gt3.kmer15.(130000.132000).V23.E32.cyc100.graph")
+    test_min_flow_decomp(filename = "tests/cyclic_graphs/gt5.kmer27.(1300000.1400000).V809.E1091.mincyc1000.graph")
+    # test_least_abs_errors(filename = "tests/cyclic_graphs/gt5.kmer27.(655000.660000).V18.E27.mincyc4.e0.75.graph")
+    # test_min_path_error(filename = "tests/cyclic_graphs/gt5.kmer27.(655000.660000).V18.E27.mincyc4.e0.75.graph")
 
 if __name__ == "__main__":
     # Configure logging

flowpaths/abstractwalkmodeldigraph.py

@@ -379,7 +379,7 @@ def _apply_safety_optimizations(self):
                         try:
                             if not self.optimize_with_safe_sequences_fix_via_bounds:
                                 raise Exception("throw")
-                            self.solver.fix_variable(self.edge_vars[(u, v, i)], 1)
+                            self.solver.fix_variable(self.edge_vars[(u, v, i)], int(1))
                         except Exception:
                             # Fallback: keep old behaviour if fixing fails for some backend edge case
                             self.solver.add_constraint(

flowpaths/utils/solverwrapper.py

@@ -733,6 +733,7 @@ def fix_variable(self, var, value: Union[int, float]):
         value : int | float
             The value to which the variable should be fixed.
         """
+
         # Normalize to float for solvers expecting floating bounds
         value = float(value)
         if self.external_solver == "gurobi":
@@ -746,20 +747,11 @@ def fix_variable(self, var, value: Union[int, float]):
         elif self.external_solver == "highs":
             # HiGHS: change column bounds using internal index of variable
             try:
-                # Attempt a few common attribute names to locate the column index
-                idx = None
-                for cand in ["index", "col", "idx"]:
-                    if hasattr(var, cand):
-                        idx = getattr(var, cand)
-                        break
-                if idx is None:
-                    raise AttributeError("Variable has no index attribute among ['index','col','idx']")
-                # Ensure numpy imported (already imported as np at top)
                 self.solver.changeColsBounds(
                     1,
-                    np.array([idx], dtype=np.int32),
-                    np.array([value], dtype=np.float64 if isinstance(value, float) else np.int32),
-                    np.array([value], dtype=np.float64 if isinstance(value, float) else np.int32),
+                    np.array([var.index], dtype=np.int32),
+                    np.array([value], dtype=np.float64 if isinstance(value, float) else np.int64),
+                    np.array([value], dtype=np.float64 if isinstance(value, float) else np.int64),
                 )
             except Exception as e:
                 utils.logger.error(f"{__name__}: Could not fix highs variable: {e}")