Merge branch 'master' into master

Author: FabianHofmann

.github/workflows/claude.yml

@@ -31,7 +31,7 @@ jobs:
       id-token: write
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 1
 

.github/workflows/codeql.yml

@@ -55,11 +55,11 @@ jobs:
         # your codebase is analyzed, see https://docs.github.com/en/code-security/code-scanning/creating-an-advanced-setup-for-code-scanning/codeql-code-scanning-for-compiled-languages
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v3
+      uses: github/codeql-action/init@v4
       with:
         languages: ${{ matrix.language }}
         build-mode: ${{ matrix.build-mode }}
@@ -87,6 +87,6 @@ jobs:
         exit 1
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v3
+      uses: github/codeql-action/analyze@v4
       with:
         category: "/language:${{matrix.language}}"

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
     name: Build and verify package
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: hynek/build-and-inspect-python-package@v2
 
   release:
@@ -20,7 +20,7 @@ jobs:
     needs: [build]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: softprops/action-gh-release@v2
         with:
           generate_release_notes: true
@@ -36,7 +36,7 @@ jobs:
     permissions:
       id-token: write
     steps:
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v6
         with:
           name: Packages
           path: dist

.github/workflows/test-models.yml

@@ -31,7 +31,7 @@ jobs:
         shell: bash -l {0}
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           repository: PyPSA/pypsa-eur
           ref: master
@@ -101,7 +101,7 @@ jobs:
 
       - name: Upload artifacts
         if: env.pinned == 'false'
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: results-pypsa-eur-${{ matrix.version }}
           path: |

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
     name: Build and verify package
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0 # Needed for setuptools_scm
       - uses: hynek/build-and-inspect-python-package@v2
@@ -42,7 +42,7 @@ jobs:
         - windows-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0 # Needed for setuptools_scm
 
@@ -74,7 +74,7 @@ jobs:
         choco install glpk
 
     - name: Download package
-      uses: actions/download-artifact@v5
+      uses: actions/download-artifact@v6
       with:
         name: Packages
         path: dist
@@ -102,7 +102,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0 # Needed for setuptools_scm
 
@@ -112,7 +112,7 @@ jobs:
         python-version: 3.12
 
     - name: Download package
-      uses: actions/download-artifact@v5
+      uses: actions/download-artifact@v6
       with:
         name: Packages
         path: dist

doc/release_notes.rst

@@ -1,26 +1,48 @@
 Release Notes
 =============
 
-Upcoming Version
+.. Upcoming Version
+
+* Fix compatibility for xpress versions below 9.6 (regression)
+* Performance: Up to 50x faster ``repr()`` for variables/constraints via O(log n) label lookup and direct numpy indexing
+* Performance: Up to 46x faster ``ncons`` property by replacing ``.flat.labels.unique()`` with direct counting
+* Add support for GPU-accelerated solver [cuPDLPx](https://github.com/MIT-Lu-Lab/cuPDLPx)
+
+Version 0.5.8
+--------------
 
 * Replace pandas-based LP file writing with polars implementation for significantly improved performance on large models
 * Consolidate "lp" and "lp-polars" io_api options - both now use the optimized polars backend
 * Reduced memory usage and faster file I/O operations when exporting models to LP format
-* Improved constraint equality check in `linopy.testing.assert_conequal` to less strict optionally
 * Minor bugfix for multiplying variables with numpy type constants
 * Harmonize dtypes before concatenation in lp file writing to avoid dtype mismatch errors. This error occurred when creating and storing models in netcdf format using windows machines and loading and solving them on linux machines.
 * Add option to use polars series as constant input
 * Fix expression merge to explicitly use outer join when combining expressions with disjoint coordinates for consistent behavior across xarray versions
-* Add support for GPU-accelerated solver [cuPDLPx](https://github.com/MIT-Lu-Lab/cuPDLPx)
+* Adding xpress postsolve if necessary
+* Handle ImportError in xpress import
+* Fetch and display OETC worker error logs
+* Fix windows permission error when dumping model file
+* Performance improvements for xpress solver using C interface
+
+Version 0.5.7
+--------------
+
+* Removed deprecated future warning for scalar get item operations
+* Silenced version output from the HiGHS solver
+* Mosek: Remove explicit use of Env, use global env instead
+* Objectives can now be created from variables via `linopy.Model.add_objective`
+* Added integration with OETC platform (refactored implementation)
+* Add error message if highspy is not installed
+* Fix MindOpt floating release issue
+* Made merge expressions function infer class without triggering warnings
+* Improved testing coverage
+* Fix pypsa-eur environment path in CI
 
 Version 0.5.6
 --------------
 
 * Improved variable/expression arithmetic methods so that they correctly handle types
 * Gurobi: Pass dictionary as env argument `env={...}` through to gurobi env creation
-* Added integration with OETC platform
-* Mosek: Remove explicit use of Env, use global env instead
-* Objectives can now be created from variables via `linopy.Model.add_objective`.
 
 **Breaking Changes**
 

linopy/common.py

@@ -750,7 +750,118 @@ def get_dims_with_index_levels(
     return dims_with_levels
 
 
-def get_label_position(
+class LabelPositionIndex:
+    """
+    Index for fast O(log n) lookup of label positions using binary search.
+
+    This class builds a sorted index of label ranges and uses binary search
+    to find which container (variable/constraint) a label belongs to.
+
+    Parameters
+    ----------
+    obj : Any
+        Container object with items() method returning (name, val) pairs,
+        where val has .labels and .range attributes.
+    """
+
+    __slots__ = ("_starts", "_names", "_obj", "_built")
+
+    def __init__(self, obj: Any) -> None:
+        self._obj = obj
+        self._starts: np.ndarray | None = None
+        self._names: list[str] | None = None
+        self._built = False
+
+    def _build_index(self) -> None:
+        """Build the sorted index of label ranges."""
+        if self._built:
+            return
+
+        ranges = []
+        for name, val in self._obj.items():
+            start, stop = val.range
+            ranges.append((start, name))
+
+        # Sort by start value
+        ranges.sort(key=lambda x: x[0])
+        self._starts = np.array([r[0] for r in ranges])
+        self._names = [r[1] for r in ranges]
+        self._built = True
+
+    def invalidate(self) -> None:
+        """Invalidate the index (call when items are added/removed)."""
+        self._built = False
+        self._starts = None
+        self._names = None
+
+    def find_single(self, value: int) -> tuple[str, dict] | tuple[None, None]:
+        """Find the name and coordinates for a single label value."""
+        if value == -1:
+            return None, None
+
+        self._build_index()
+        starts = self._starts
+        names = self._names
+        assert starts is not None and names is not None
+
+        # Binary search to find the right range
+        idx = int(np.searchsorted(starts, value, side="right")) - 1
+
+        if idx < 0 or idx >= len(starts):
+            raise ValueError(f"Label {value} is not existent in the model.")
+
+        name = names[idx]
+        val = self._obj[name]
+        start, stop = val.range
+
+        # Verify the value is in range
+        if value < start or value >= stop:
+            raise ValueError(f"Label {value} is not existent in the model.")
+
+        labels = val.labels
+        index = np.unravel_index(value - start, labels.shape)
+        coord = {dim: labels.indexes[dim][i] for dim, i in zip(labels.dims, index)}
+        return name, coord
+
+    def find_single_with_index(
+        self, value: int
+    ) -> tuple[str, dict, tuple[int, ...]] | tuple[None, None, None]:
+        """
+        Find name, coordinates, and raw numpy index for a single label value.
+
+        Returns (name, coord, index) where index is a tuple of integers that
+        can be used for direct numpy indexing (e.g., arr.values[index]).
+        This avoids the overhead of xarray's .sel() method.
+        """
+        if value == -1:
+            return None, None, None
+
+        self._build_index()
+        starts = self._starts
+        names = self._names
+        assert starts is not None and names is not None
+
+        # Binary search to find the right range
+        idx = int(np.searchsorted(starts, value, side="right")) - 1
+
+        if idx < 0 or idx >= len(starts):
+            raise ValueError(f"Label {value} is not existent in the model.")
+
+        name = names[idx]
+        val = self._obj[name]
+        start, stop = val.range
+
+        # Verify the value is in range
+        if value < start or value >= stop:
+            raise ValueError(f"Label {value} is not existent in the model.")
+
+        labels = val.labels
+        index = np.unravel_index(value - start, labels.shape)
+        coord = {dim: labels.indexes[dim][i] for dim, i in zip(labels.dims, index)}
+        return name, coord, index
+
+
+def _get_label_position_linear(
     obj: Any, values: int | np.ndarray
 ) -> (
     tuple[str, dict]
@@ -760,6 +871,9 @@ def get_label_position(
 ):
     """
     Get tuple of name and coordinate for variable labels.
+
+    This is the original O(n) implementation that scans through all items.
+    Used only for testing/benchmarking comparisons.
     """
 
     def find_single(value: int) -> tuple[str, dict] | tuple[None, None]:
@@ -795,6 +909,53 @@ def find_single(value: int) -> tuple[str, dict] | tuple[None, None]:
         raise ValueError("Array's with more than two dimensions is not supported")
 
 
+def get_label_position(
+    obj: Any,
+    values: int | np.ndarray,
+    index: LabelPositionIndex | None = None,
+) -> (
+    tuple[str, dict]
+    | tuple[None, None]
+    | list[tuple[str, dict] | tuple[None, None]]
+    | list[list[tuple[str, dict] | tuple[None, None]]]
+):
+    """
+    Get tuple of name and coordinate for variable labels.
+
+    Uses O(log n) binary search with a cached index for fast lookups.
+
+    Parameters
+    ----------
+    obj : Any
+        Container object with items() method (Variables or Constraints).
+    values : int or np.ndarray
+        Label value(s) to look up.
+    index : LabelPositionIndex, optional
+        Pre-built index for fast lookups. If None, one will be created.
+
+    Returns
+    -------
+    tuple or list
+        (name, coord) tuple for single values, or list of tuples for arrays.
+    """
+    if index is None:
+        index = LabelPositionIndex(obj)
+
+    if isinstance(values, int):
+        return index.find_single(values)
+
+    values = np.array(values)
+    ndim = values.ndim
+    if ndim == 0:
+        return index.find_single(values.item())
+    elif ndim == 1:
+        return [index.find_single(int(v)) for v in values]
+    elif ndim == 2:
+        return [[index.find_single(int(v)) for v in col] for col in values.T]
+    else:
+        raise ValueError("Array's with more than two dimensions is not supported")
+
+
 def print_coord(coord: dict[str, Any] | Iterable[Any]) -> str:
     """
     Format coordinates into a string representation.
@@ -838,14 +999,16 @@ def print_single_variable(model: Any, label: int) -> str:
         return "None"
 
     variables = model.variables
-    name, coord = variables.get_label_position(label)
+    name, coord, index = variables.get_label_position_with_index(label)
 
-    lower = variables[name].lower.sel(coord).item()
-    upper = variables[name].upper.sel(coord).item()
+    var = variables[name]
+    # Use direct numpy indexing instead of .sel() for performance
+    lower = var.lower.values[index]
+    upper = var.upper.values[index]
 
-    if variables[name].attrs["binary"]:
+    if var.attrs["binary"]:
         bounds = " ∈ {0, 1}"
-    elif variables[name].attrs["integer"]:
+    elif var.attrs["integer"]:
         bounds = f" ∈ Z ⋂ [{lower:.4g},...,{upper:.4g}]"
     else:
         bounds = f" ∈ [{lower:.4g}, {upper:.4g}]"