⚡️ Speed up method GridBox._get_children by 41%

[codeflash-ai]

📄 41% (0.41x) speedup for GridBox._get_children in panel/layout/grid.py

⏱️ Runtime : 20.8 milliseconds → 14.8 milliseconds (best of 50 runs)

📝 Explanation and details

The optimized code achieves a 40% speedup through several key optimizations:

1. Namedtuple Caching
The biggest improvement comes from caching namedtuple definitions as class attributes (cls._Item, cls._Grid) instead of recreating them on every call. The line profiler shows this optimization alone saves ~5.7ms (from 5.77ms to 0.17ms) by eliminating repeated namedtuple construction overhead.

2. Method Reference Caching
The code caches list.append method references (append_child = children.append, append_item = items.append) to avoid repeated attribute lookups in tight loops. This micro-optimization reduces overhead when building result lists.

3. Loop Structure Improvements
In _get_children, the list comprehension for creating rows is replaced with an explicit loop using cached append references, reducing function call overhead for large grids.

4. Minor Optimizations

• Changed while b != 0: to while b: in the GCD function
• Used tuple unpacking in loops for slightly better performance
• Converted lambda to regular function to avoid lambda overhead

Performance Characteristics:

• Small grids (2-10 elements): 400-800% speedup due to namedtuple caching dominating overhead
• Medium grids (100 elements): 75-400% speedup from combined optimizations
• Large grids (1000+ elements): 25-30% speedup as computational work dominates, but still benefits from reduced overhead

The optimizations are most effective for workloads with frequent small-to-medium grid operations where the setup overhead previously dominated execution time.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 42 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

import math
from collections import namedtuple

# imports
import pytest
from panel.layout.grid import GridBox


# Helper: Dummy objects to use as children
class Dummy:
    def __init__(self, name):
        self.name = name
    def __repr__(self):
        return f"Dummy({self.name!r})"
    def __eq__(self, other):
        return isinstance(other, Dummy) and self.name == other.name
    def __hash__(self):
        return hash(self.name)

# -------------------- UNIT TESTS --------------------

# 1. BASIC TEST CASES

def test_empty_children_list():
    # Should return an empty list when no children are given
    codeflash_output = GridBox._get_children([]) # 97.6μs -> 5.80μs (1584% faster)

def test_single_child():
    # Should return a single child at position (0,0) with span (1,1)
    d = Dummy("a")
    codeflash_output = GridBox._get_children([d]); result = codeflash_output # 99.1μs -> 10.7μs (827% faster)

def test_two_children_flat():
    # Two children, default layout (should be column)
    a, b = Dummy("a"), Dummy("b")
    codeflash_output = GridBox._get_children([a, b]); result = codeflash_output # 102μs -> 13.2μs (674% faster)

def test_two_children_with_ncols():
    # Two children, force two columns (single row)
    a, b = Dummy("a"), Dummy("b")
    codeflash_output = GridBox._get_children([a, b], ncols=2); result = codeflash_output # 107μs -> 15.8μs (579% faster)

def test_two_children_with_nrows():
    # Two children, force two rows (single column)
    a, b = Dummy("a"), Dummy("b")
    codeflash_output = GridBox._get_children([a, b], nrows=2); result = codeflash_output # 104μs -> 16.9μs (520% faster)

def test_three_children_ncols_2():
    # Three children, two columns
    a, b, c = Dummy("a"), Dummy("b"), Dummy("c")
    codeflash_output = GridBox._get_children([a, b, c], ncols=2); result = codeflash_output # 108μs -> 18.6μs (482% faster)

def test_three_children_nrows_2():
    # Three children, two rows
    a, b, c = Dummy("a"), Dummy("b"), Dummy("c")
    codeflash_output = GridBox._get_children([a, b, c], nrows=2); result = codeflash_output # 107μs -> 17.8μs (501% faster)

def test_nested_list():
    # Nested list of children: [[a, b], [c, d]]
    a, b, c, d = Dummy("a"), Dummy("b"), Dummy("c"), Dummy("d")
    children = [[a, b], [c, d]]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 108μs -> 20.9μs (421% faster)

# 2. EDGE TEST CASES

def test_empty_nested_lists():
    # Nested empty lists should result in empty output
    codeflash_output = GridBox._get_children([[], []]) # 97.6μs -> 8.36μs (1066% faster)

def test_irregular_nested_lists():
    # Nested lists with different lengths (ragged)
    a, b, c = Dummy("a"), Dummy("b"), Dummy("c")
    children = [[a, b], [c]]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 108μs -> 19.5μs (456% faster)

def test_none_in_children():
    # None as a child should be included as a layout cell
    a, b = Dummy("a"), Dummy("b")
    children = [a, None, b]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 102μs -> 14.0μs (632% faster)

def test_ncols_exceeds_children():
    # ncols greater than number of children
    a, b = Dummy("a"), Dummy("b")
    codeflash_output = GridBox._get_children([a, b], ncols=5); result = codeflash_output # 103μs -> 15.4μs (577% faster)

def test_nrows_exceeds_children():
    # nrows greater than number of children
    a, b = Dummy("a"), Dummy("b")
    codeflash_output = GridBox._get_children([a, b], nrows=5); result = codeflash_output # 104μs -> 16.8μs (520% faster)


def test_zero_nrows():
    # nrows=0 should raise ZeroDivisionError or ValueError
    a, b = Dummy("a"), Dummy("b")
    with pytest.raises(ZeroDivisionError):
        GridBox._get_children([a, b], nrows=0) # 2.08μs -> 2.02μs (3.02% faster)

def test_large_gap_in_nested_lists():
    # Deeply nested with empty lists in between
    a, b = Dummy("a"), Dummy("b")
    children = [[[], [a]], [], [b]]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 133μs -> 25.2μs (428% faster)

def test_single_child_nested():
    # Single child nested in multiple lists
    a = Dummy("a")
    children = [[[a]]]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 108μs -> 15.1μs (618% faster)

def test_list_with_only_none():
    # Only None in children
    children = [None, None]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 104μs -> 12.7μs (721% faster)

# 3. LARGE SCALE TEST CASES

def test_large_flat_list_ncols():
    # 1000 children, 10 columns
    children = [Dummy(str(i)) for i in range(1000)]
    codeflash_output = GridBox._get_children(children, ncols=10); result = codeflash_output # 1.42ms -> 1.11ms (28.0% faster)

def test_large_flat_list_nrows():
    # 1000 children, 10 rows
    children = [Dummy(str(i)) for i in range(1000)]
    codeflash_output = GridBox._get_children(children, nrows=10); result = codeflash_output # 1.22ms -> 955μs (27.2% faster)

def test_large_nested_list():
    # 10x10 nested grid (100 elements)
    children = [[Dummy(f"{i},{j}") for j in range(10)] for i in range(10)]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 254μs -> 143μs (77.2% faster)

def test_large_irregular_nested_list():
    # 100 lists, each with i elements (triangular array)
    children = [ [Dummy(f"{i},{j}") for j in range(i)] for i in range(1, 101) ]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 6.64ms -> 5.84ms (13.8% faster)

def test_large_list_with_nones():
    # 1000 elements, every 10th is None
    children = [Dummy(str(i)) if i % 10 else None for i in range(1000)]
    codeflash_output = GridBox._get_children(children, ncols=10); result = codeflash_output # 1.40ms -> 1.09ms (28.5% faster)
    # Check that None appears in the correct places
    for i in range(0, 1000, 10):
        pass
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
import math

# imports
import pytest
from panel.layout.grid import GridBox


# Helper function to generate dummy objects for testing
def dummy_obj(label):
    # Just a unique object per label
    return f"obj_{label}"

# ------------------ UNIT TESTS ------------------

# 1. Basic Test Cases

def test_single_object():
    # Test with a single child, no nrows/ncols
    children = [dummy_obj("a")]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 117μs -> 12.8μs (813% faster)

def test_two_objects_row():
    # Test with two children, ncols=2 (should be one row, two columns)
    children = [dummy_obj("a"), dummy_obj("b")]
    codeflash_output = GridBox._get_children(children, nrows=1, ncols=2); result = codeflash_output # 108μs -> 16.7μs (550% faster)

def test_two_objects_col():
    # Test with two children, nrows=2 (should be two rows, one column)
    children = [dummy_obj("a"), dummy_obj("b")]
    codeflash_output = GridBox._get_children(children, nrows=2); result = codeflash_output # 109μs -> 17.3μs (531% faster)

def test_three_objects_auto_ncols():
    # Test with three children, nrows=2, ncols not specified (should auto-calculate ncols=2)
    children = [dummy_obj("a"), dummy_obj("b"), dummy_obj("c")]
    codeflash_output = GridBox._get_children(children, nrows=2); result = codeflash_output # 109μs -> 18.4μs (496% faster)

def test_nested_list_basic():
    # Test with nested list input (should alternate col/row)
    children = [[dummy_obj("a"), dummy_obj("b")], [dummy_obj("c")]]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 111μs -> 19.8μs (463% faster)

# 2. Edge Test Cases

def test_empty_children():
    # Test with empty children list
    children = []
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 93.8μs -> 5.38μs (1642% faster)

def test_empty_nested_list():
    # Test with nested empty lists
    children = [[], []]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 99.7μs -> 8.96μs (1013% faster)

def test_none_in_children():
    # Test with None as a child (should include None as layout)
    children = [None]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 99.6μs -> 10.6μs (840% faster)

def test_mixed_none_and_objects():
    # Test with mixture of None and objects
    children = [dummy_obj("a"), None, dummy_obj("b")]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 104μs -> 14.6μs (616% faster)

def test_large_nrows_ncols_exceeding_children():
    # Test with nrows and ncols greater than number of children
    children = [dummy_obj("a"), dummy_obj("b")]
    codeflash_output = GridBox._get_children(children, nrows=5, ncols=5); result = codeflash_output # 103μs -> 15.2μs (584% faster)

def test_non_rectangular_nested_list():
    # Test with jagged nested list
    children = [[dummy_obj("a")], [dummy_obj("b"), dummy_obj("c")]]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 110μs -> 20.1μs (450% faster)

def test_deeply_nested_list():
    # Test with deeply nested lists
    children = [[[dummy_obj("a")], [dummy_obj("b")]], [[dummy_obj("c")]]]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 117μs -> 25.3μs (364% faster)

def test_non_list_input():
    # Test with a single non-list input (should treat as single cell)
    children = dummy_obj("a")
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 92.8μs -> 4.89μs (1796% faster)

def test_single_row_multiple_columns():
    # Test with nrows=1 and multiple children
    children = [dummy_obj("a"), dummy_obj("b"), dummy_obj("c")]
    codeflash_output = GridBox._get_children(children, nrows=1); result = codeflash_output # 106μs -> 17.0μs (523% faster)

def test_single_column_multiple_rows():
    # Test with ncols=1 and multiple children
    children = [dummy_obj("a"), dummy_obj("b"), dummy_obj("c")]
    codeflash_output = GridBox._get_children(children, ncols=1); result = codeflash_output # 109μs -> 19.7μs (455% faster)

# 3. Large Scale Test Cases

def test_large_flat_list():
    # Test with a large flat list of children (up to 1000 elements)
    children = [dummy_obj(i) for i in range(1000)]
    codeflash_output = GridBox._get_children(children, nrows=100, ncols=10); result = codeflash_output # 1.39ms -> 1.09ms (27.1% faster)
    # Check that each object is placed correctly
    for idx, (obj, r, c, h, w) in enumerate(result):
        expected_obj = dummy_obj(idx)

def test_large_nested_list():
    # Test with a large nested list (10 lists of 100 elements)
    children = [[dummy_obj(f"{i}-{j}") for j in range(100)] for i in range(10)]
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 1.34ms -> 1.07ms (24.3% faster)
    # Check that each object is present
    expected_objs = set(dummy_obj(f"{i}-{j}") for i in range(10) for j in range(100))
    found_objs = set(obj for (obj, _, _, _, _) in result)

def test_large_jagged_nested_list():
    # Test with jagged nested list (varying lengths)
    children = []
    for i in range(10):
        children.append([dummy_obj(f"{i}-{j}") for j in range(i+1)])
    codeflash_output = GridBox._get_children(children); result = codeflash_output # 202μs -> 95.2μs (113% faster)
    # Total number of objects
    total = sum(range(1, 11))
    # Check positions are unique
    positions = set((r, c) for (_, r, c, _, _) in result)

def test_large_flat_list_single_row():
    # Test with large flat list, single row
    children = [dummy_obj(i) for i in range(1000)]
    codeflash_output = GridBox._get_children(children, nrows=1); result = codeflash_output # 1.23ms -> 958μs (27.9% faster)
    # All should be in row 0
    for obj, r, c, h, w in result:
        pass

def test_large_flat_list_single_column():
    # Test with large flat list, single column
    children = [dummy_obj(i) for i in range(1000)]
    codeflash_output = GridBox._get_children(children, ncols=1); result = codeflash_output # 2.46ms -> 2.00ms (23.0% faster)
    # All should be in column 0
    for obj, r, c, h, w in result:
        pass
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

To edit these changes git checkout codeflash/optimize-GridBox._get_children-mhbzhpqv and push.