⚡️ Speed up method PandasIndexingAdapter._vindex_get by 5%

[codeflash-ai]

📄 5% (0.05x) speedup for PandasIndexingAdapter._vindex_get in xarray/core/indexing.py

⏱️ Runtime : 1.57 milliseconds → 1.49 milliseconds (best of 26 runs)

📝 Explanation and details

The optimization applies a conditional type check to avoid redundant function calls in the PandasIndexingAdapter.__init__ method. The key change is:

# Original: Always calls safe_cast_to_index
self.array = safe_cast_to_index(array)

# Optimized: Only calls safe_cast_to_index if not already a pd.Index
self.array = safe_cast_to_index(array) if not isinstance(array, pd.Index) else array

Why this optimization works:

• safe_cast_to_index performs type checking and conversion logic, but if the input is already a pd.Index, it simply returns the same object unchanged
• By adding an isinstance(array, pd.Index) check upfront, we skip the entire function call overhead when the array is already the correct type
• This eliminates the cost of function call dispatch, internal type checking within safe_cast_to_index, and potential object wrapping/unwrapping

Performance impact:

• The 5% speedup suggests this optimization is beneficial when PandasIndexingAdapter is frequently instantiated with objects that are already pd.Index instances
• The micro-optimization reduces CPU cycles spent on redundant type validation and function call overhead
• Since pandas Index objects are commonly passed around in xarray's indexing operations, this fast-path gets exercised frequently

Test case suitability:
This optimization is most effective when the array parameter is already a pd.Index object, which appears to be a common case in xarray's internal data processing pipelines where pandas indexes are frequently reused and passed between components.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	🔘 None Found
⏪ Replay Tests	✅ 36 Passed
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	66.7%

⏪ Replay Tests and Runtime

Test File::Test Function	Original ⏱️	Optimized ⏱️	Speedup
test_pytest_xarrayteststest_concat_py_xarrayteststest_computation_py_xarrayteststest_formatting_py_xarray__replay_test_0.py::test_xarray_core_indexing_PandasIndexingAdapter__vindex_get	705μs	688μs	2.55%✅

To edit these changes git checkout codeflash/optimize-PandasIndexingAdapter._vindex_get-mja629j0 and push.