feat: move set_int_index to solution assignment in model.py

Author: FabianHofmann

doc/release_notes.rst

@@ -1,8 +1,10 @@
 Release Notes
 =============
 
-.. Upcoming Version
-.. ----------------
+Upcoming Version
+----------------
+
+* The internal handling of `Solution` objects was improved for more consistency. Solution objects created from solver calls now preserve the exact index names from the input file, ensuring consistent behavior across all solver functions.
 
 Version 0.4.4
 --------------

linopy/common.py

@@ -38,6 +38,16 @@
     from linopy.variables import Variable
 
 
+def set_int_index(series: pd.Series) -> pd.Series:
+    """
+    Convert string index to int index.
+    """
+    if not series.empty and not series.index.is_integer():
+        cutoff = count_initial_letters(str(series.index[0]))
+        series.index = series.index.str[cutoff:].astype(int)
+    return series
+
+
 def maybe_replace_sign(sign: str) -> str:
     """
     Replace the sign with an alternative sign if available.

linopy/model.py

@@ -30,6 +30,7 @@
     best_int,
     maybe_replace_signs,
     replace_by_map,
+    set_int_index,
     to_path,
 )
 from linopy.constants import (
@@ -1189,6 +1190,7 @@ def solve(
 
         # map solution and dual to original shape which includes missing values
         sol = result.solution.primal.copy()
+        sol = set_int_index(sol)
         sol.loc[-1] = nan
 
         for name, var in self.variables.items():
@@ -1201,6 +1203,7 @@ def solve(
 
         if not result.solution.dual.empty:
             dual = result.solution.dual.copy()
+            dual = set_int_index(dual)
             dual.loc[-1] = nan
 
             for name, con in self.constraints.items():

linopy/solvers.py

@@ -19,9 +19,7 @@
 
 import numpy as np
 import pandas as pd
-from pandas.core.series import Series
 
-from linopy.common import count_initial_letters
 from linopy.constants import (
     Result,
     Solution,
@@ -135,16 +133,6 @@
 )
 
 
-def set_int_index(series: Series) -> Series:
-    """
-    Convert string index to int index.
-    """
-    if not series.empty:
-        cutoff = count_initial_letters(str(series.index[0]))
-        series.index = series.index.str[cutoff:].astype(int)
-    return series
-
-
 # using enum to match solver subclasses with names
 class SolverName(enum.Enum):
     CBC = "cbc"
@@ -466,8 +454,8 @@ def get_solver_solution():
             )
             variables_b = df.index.str[0] == "x"
 
-            sol = df[variables_b][2].pipe(set_int_index)
-            dual = df[~variables_b][3].pipe(set_int_index)
+            sol = df[variables_b][2]
+            dual = df[~variables_b][3]
             return Solution(sol, dual, objective)
 
         solution = self.safe_get_solution(status=status, func=get_solver_solution)
@@ -624,11 +612,7 @@ def get_solver_solution() -> Solution:
             dual_io = io.StringIO("".join(read_until_break(f))[:-2])
             dual_ = pd.read_fwf(dual_io)[1:].set_index("Row name")
             if "Marginal" in dual_:
-                dual = (
-                    pd.to_numeric(dual_["Marginal"], "coerce")
-                    .fillna(0)
-                    .pipe(set_int_index)
-                )
+                dual = pd.to_numeric(dual_["Marginal"], "coerce").fillna(0)
             else:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -638,7 +622,6 @@ def get_solver_solution() -> Solution:
                 pd.read_fwf(sol_io)[1:]
                 .set_index("Column name")["Activity"]
                 .astype(float)
-                .pipe(set_int_index)
             )
             f.close()
             return Solution(sol, dual, objective)
@@ -860,12 +843,8 @@ def get_solver_solution() -> Solution:
                 sol = pd.Series(solution.col_value, model.matrices.vlabels, dtype=float)
                 dual = pd.Series(solution.row_dual, model.matrices.clabels, dtype=float)
             else:
-                sol = pd.Series(
-                    solution.col_value, h.getLp().col_names_, dtype=float
-                ).pipe(set_int_index)
-                dual = pd.Series(
-                    solution.row_dual, h.getLp().row_names_, dtype=float
-                ).pipe(set_int_index)
+                sol = pd.Series(solution.col_value, h.getLp().col_names_, dtype=float)
+                dual = pd.Series(solution.row_dual, h.getLp().row_names_, dtype=float)
 
             return Solution(sol, dual, objective)
 
@@ -1084,13 +1063,11 @@ def get_solver_solution() -> Solution:
             objective = m.ObjVal
 
             sol = pd.Series({v.VarName: v.x for v in m.getVars()}, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = pd.Series(
                     {c.ConstrName: c.Pi for c in m.getConstrs()}, dtype=float
                 )
-                dual = set_int_index(dual)
             except AttributeError:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1229,15 +1206,13 @@ def get_solver_solution() -> Solution:
             solution = pd.Series(
                 m.solution.get_values(), m.variables.get_names(), dtype=float
             )
-            solution = set_int_index(solution)
 
             if is_lp:
                 dual = pd.Series(
                     m.solution.get_dual_values(),
                     m.linear_constraints.get_names(),
                     dtype=float,
                 )
-                dual = set_int_index(dual)
             else:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1366,15 +1341,13 @@ def get_solver_solution() -> Solution:
             sol.drop(
                 ["quadobjvar", "qmatrixvar"], errors="ignore", inplace=True, axis=0
             )
-            sol = set_int_index(sol)
 
             cons = m.getConss()
             if len(cons) != 0:
                 dual = pd.Series({c.name: m.getDualSolVal(c) for c in cons})
                 dual = dual[
                     dual.index.str.startswith("c") & ~dual.index.str.startswith("cf")
                 ]
-                dual = set_int_index(dual)
             else:
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1504,12 +1477,10 @@ def get_solver_solution() -> Solution:
             var = [str(v) for v in m.getVariable()]
 
             sol = pd.Series(m.getSolution(var), index=var, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual_ = [str(d) for d in m.getConstraint()]
                 dual = pd.Series(m.getDual(dual_), index=dual_, dtype=float)
-                dual = set_int_index(dual)
             except (xpress.SolverError, xpress.ModelError, SystemError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1833,13 +1804,11 @@ def get_solver_solution() -> Solution:
             sol = m.getxx(soltype)
             sol = {m.getvarname(i): sol[i] for i in range(m.getnumvar())}
             sol = pd.Series(sol, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = m.gety(soltype)
                 dual = {m.getconname(i): dual[i] for i in range(m.getnumcon())}
                 dual = pd.Series(dual, dtype=float)
-                dual = set_int_index(dual)
             except (mosek.Error, AttributeError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -1975,11 +1944,9 @@ def get_solver_solution() -> Solution:
             objective = m.BestObj if m.ismip else m.LpObjVal
 
             sol = pd.Series({v.name: v.x for v in m.getVars()}, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = pd.Series({v.name: v.pi for v in m.getConstrs()}, dtype=float)
-                dual = set_int_index(dual)
             except (coptpy.CoptError, AttributeError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)
@@ -2119,11 +2086,9 @@ def get_solver_solution() -> Solution:
             objective = m.objval
 
             sol = pd.Series({v.varname: v.X for v in m.getVars()}, dtype=float)
-            sol = set_int_index(sol)
 
             try:
                 dual = pd.Series({c.constrname: c.DualSoln for c in m.getConstrs()})
-                dual = set_int_index(dual)
             except (mindoptpy.MindoptError, AttributeError):
                 logger.warning("Dual values of MILP couldn't be parsed")
                 dual = pd.Series(dtype=float)

linopy/variables.py

@@ -47,12 +47,12 @@
     print_coord,
     print_single_variable,
     save_join,
+    set_int_index,
     to_dataframe,
     to_polars,
 )
 from linopy.config import options
 from linopy.constants import HELPER_DIMS, TERM_DIM
-from linopy.solvers import set_int_index
 from linopy.types import NotImplementedType
 
 if TYPE_CHECKING: