⚡️ Speed up function _cached_joined by 82%

[codeflash-ai]

📄 82% (0.82x) speedup for _cached_joined in code_to_optimize/code_directories/simple_tracer_e2e/workload.py

⏱️ Runtime : 69.8 milliseconds → 38.4 milliseconds (best of 129 runs)

📝 Explanation and details

Here’s a significantly faster version of your code.

• Don't use a list comprehension to build the list: " ".join(map(str, range(number))) is slightly faster and uses less memory.
• The lru_cache overhead isn’t necessary if the only cache size you need is 1001 and the argument number is a small integer. It's faster and lower overhead to use a simple dict for caching, and you can control the cache size yourself.
• Precompute the string results only as needed.

Here’s the optimized version.

Notes:

• " ".join(map(str, ...)) is faster and more memory-efficient than a list comprehension here.
• This is an efficient, custom, fixed-size LRU cache tailored for this use-case (integer argument, up to 1001 cache entries).
• If threading isn’t needed, you can safely remove Lock/with usage for a slightly faster single-threaded version.
• The function signature and return value are unchanged.
• All original comments (the single one) are still accurate: "map(str, ...)" is used for faster conversion.

If you want the absolutely highest performance in a single-threaded setting, drop the Lock.

Either way, you get better performance and lower memory per invocation.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 2059 Passed
⏪ Replay Tests	✅ 3 Passed
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

from functools import lru_cache

# imports
import pytest  # used for our unit tests
from workload import _cached_joined

# unit tests

# -------------------------
# Basic Test Cases
# -------------------------

def test_joined_zero():
    # Test with number=0, should return empty string
    codeflash_output = _cached_joined(0) # 1.55μs -> 3.86μs (59.8% slower)

def test_joined_one():
    # Test with number=1, should return "0"
    codeflash_output = _cached_joined(1) # 1.94μs -> 4.08μs (52.4% slower)

def test_joined_small():
    # Test with number=5, should return "0 1 2 3 4"
    codeflash_output = _cached_joined(5) # 2.46μs -> 4.54μs (45.7% slower)

def test_joined_typical():
    # Test with number=10, should return "0 1 2 3 4 5 6 7 8 9"
    codeflash_output = _cached_joined(10) # 2.88μs -> 4.79μs (39.8% slower)

def test_joined_cache_basic():
    # Test that repeated calls (cache hit) return the same result
    codeflash_output = _cached_joined(7); result1 = codeflash_output # 2.54μs -> 501ns (408% faster)
    codeflash_output = _cached_joined(7); result2 = codeflash_output # 230ns -> 190ns (21.1% faster)

# -------------------------
# Edge Test Cases
# -------------------------

def test_joined_negative():
    # Negative numbers should return empty string (range(negative) is empty)
    codeflash_output = _cached_joined(-1) # 1.56μs -> 3.67μs (57.4% slower)
    codeflash_output = _cached_joined(-100) # 691ns -> 1.64μs (57.9% slower)

def test_joined_large_single_digit():
    # Test with number=10, should not include 10
    codeflash_output = _cached_joined(10); result = codeflash_output # 2.92μs -> 481ns (508% faster)

def test_joined_non_integer_input():
    # Non-integer input should raise TypeError
    with pytest.raises(TypeError):
        _cached_joined("abc")
    with pytest.raises(TypeError):
        _cached_joined(3.5)
    with pytest.raises(TypeError):
        _cached_joined(None)

def test_joined_maxsize_cache():
    # Test that cache does not fail at boundary (maxsize=1001)
    for n in [0, 1, 1000, 1001]:
        codeflash_output = _cached_joined(n); res = codeflash_output
        # Should always start with "0" if n > 0, else empty string
        if n > 0:
            pass
        else:
            pass

def test_joined_mutation_fail():
    # Ensure that the function is not off-by-one
    codeflash_output = _cached_joined(3) # 2.32μs -> 490ns (374% faster)
    codeflash_output = _cached_joined(4) # 1.18μs -> 281ns (321% faster)
    # Mutating to use range(1, number+1) or similar would fail these

def test_joined_cache_eviction():
    # Fill the cache with maxsize+1 entries and ensure older entries are evicted
    # lru_cache should evict the least recently used
    for n in range(1000):
        _cached_joined(n)
    # The first entry (n=0) should have been evicted; re-calling it should not error
    codeflash_output = _cached_joined(0)

# -------------------------
# Large Scale Test Cases
# -------------------------

def test_joined_large_scale_999():
    # Test with number=999 (near upper limit for test size)
    codeflash_output = _cached_joined(999); result = codeflash_output # 76.7μs -> 581ns (13095% faster)
    # Check length is correct (sum of all digit lengths + spaces)
    expected_length = sum(len(str(i)) for i in range(999)) + (999 - 1)

def test_joined_large_scale_1000():
    # Test with number=1000 (upper bound for reasonable test)
    codeflash_output = _cached_joined(1000); result = codeflash_output # 76.3μs -> 491ns (15442% faster)
    # Spot check a few indices
    parts = result.split(" ")

def test_joined_performance_large():
    # Not a strict performance test, but ensure it doesn't error or take too long
    # (pytest will fail if it takes too long)
    codeflash_output = _cached_joined(999); result = codeflash_output # 76.1μs -> 571ns (13226% faster)

def test_joined_cache_large_entries():
    # Test that large entries are cached and returned identically
    codeflash_output = _cached_joined(800); res1 = codeflash_output # 61.4μs -> 531ns (11456% faster)
    codeflash_output = _cached_joined(800); res2 = codeflash_output # 250ns -> 250ns (0.000% faster)

# -------------------------
# Additional Edge & Mutation-Resistant Cases
# -------------------------

@pytest.mark.parametrize("n,expected", [
    (2, "0 1"),
    (3, "0 1 2"),
    (4, "0 1 2 3"),
    (5, "0 1 2 3 4"),
])
def test_joined_parametrized(n, expected):
    # Parametrized test for small n
    codeflash_output = _cached_joined(n) # 2.29μs -> 451ns (409% faster)

def test_joined_type_consistency():
    # Ensure output is always a string
    for n in range(0, 10):
        pass

def test_joined_no_extra_spaces():
    # Should not have trailing or leading spaces
    for n in [0, 1, 5, 10, 100]:
        codeflash_output = _cached_joined(n); result = codeflash_output
        if n > 0:
            pass

def test_joined_cache_independence():
    # Ensure that calling with one value does not affect result for another
    codeflash_output = _cached_joined(7); a = codeflash_output # 2.46μs -> 471ns (423% faster)
    codeflash_output = _cached_joined(8); b = codeflash_output # 1.43μs -> 211ns (579% faster)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

from functools import lru_cache

# imports
import pytest  # used for our unit tests
from workload import _cached_joined

# unit tests

# ---------------------------
# Basic Test Cases
# ---------------------------

def test_zero():
    # Test when number is 0 (should return empty string)
    codeflash_output = _cached_joined(0) # 1.57μs -> 500ns (215% faster)

def test_one():
    # Test when number is 1 (should return '0')
    codeflash_output = _cached_joined(1) # 2.00μs -> 491ns (308% faster)

def test_small_number():
    # Test a small number (should return '0 1 2 3 4')
    codeflash_output = _cached_joined(5) # 2.58μs -> 461ns (461% faster)

def test_typical_number():
    # Test a typical number (should return correct string)
    codeflash_output = _cached_joined(10) # 2.91μs -> 411ns (607% faster)

def test_string_type_returned():
    # Test that the return type is always str
    codeflash_output = _cached_joined(5); result = codeflash_output # 2.44μs -> 390ns (524% faster)

# ---------------------------
# Edge Test Cases
# ---------------------------

def test_negative_number():
    # Negative numbers should return empty string (no range)
    codeflash_output = _cached_joined(-1) # 1.52μs -> 491ns (210% faster)
    codeflash_output = _cached_joined(-100) # 792ns -> 350ns (126% faster)

def test_large_single_digit():
    # Test for number=10, should end with '9'
    codeflash_output = _cached_joined(10); result = codeflash_output # 2.90μs -> 441ns (559% faster)

def test_non_integer_input():
    # Should raise TypeError for non-integer input
    with pytest.raises(TypeError):
        _cached_joined(5.5)
    with pytest.raises(TypeError):
        _cached_joined("10")
    with pytest.raises(TypeError):
        _cached_joined(None)

def test_large_negative_number():
    # Very large negative number should still return empty string
    codeflash_output = _cached_joined(-999) # 1.60μs -> 3.25μs (50.6% slower)

def test_boundary_cache_size():
    # Test the boundary of the cache size (maxsize=1001)
    # Should not raise or behave incorrectly at boundaries
    codeflash_output = _cached_joined(1000) # 72.9μs -> 541ns (13369% faster)
    codeflash_output = _cached_joined(1001) # 71.9μs -> 261ns (27454% faster)

def test_repeated_calls_cached():
    # Test that repeated calls with same argument return same result (cache hit)
    codeflash_output = _cached_joined(20); result1 = codeflash_output # 3.66μs -> 491ns (645% faster)
    codeflash_output = _cached_joined(20); result2 = codeflash_output # 240ns -> 221ns (8.60% faster)
    # Changing the argument should change the result
    codeflash_output = _cached_joined(21) # 2.35μs -> 190ns (1139% faster)

def test_no_trailing_space():
    # There should be no trailing space in the result
    codeflash_output = _cached_joined(8); result = codeflash_output # 2.54μs -> 430ns (492% faster)

def test_single_call_cache_eviction():
    # Test cache eviction policy does not affect correctness
    # Fill the cache with maxsize+1 distinct calls
    for i in range(1000):
        codeflash_output = _cached_joined(i); res = codeflash_output

# ---------------------------
# Large Scale Test Cases
# ---------------------------

def test_large_number_length():
    # Test with a relatively large number (e.g., 999 elements)
    n = 999
    codeflash_output = _cached_joined(n); result = codeflash_output # 76.9μs -> 641ns (11894% faster)
    expected = " ".join(str(i) for i in range(n))

def test_performance_large():
    # Test that the function does not hang or error on upper limit of cache
    n = 1000
    codeflash_output = _cached_joined(n); result = codeflash_output # 75.9μs -> 621ns (12127% faster)
    expected = " ".join(str(i) for i in range(n))

def test_large_number_start_end():
    # For a large n, check the start and end of the string
    n = 999
    codeflash_output = _cached_joined(n); result = codeflash_output # 75.9μs -> 531ns (14190% faster)

def test_large_number_correct_split():
    # For a large n, split and check all numbers are present and in order
    n = 500
    codeflash_output = _cached_joined(n); result = codeflash_output # 39.5μs -> 611ns (6361% faster)
    split = result.split(" ")

def test_large_number_type():
    # For a large n, result should still be string type
    n = 999
    codeflash_output = _cached_joined(n); result = codeflash_output # 75.9μs -> 551ns (13675% faster)
# 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-_cached_joined-mccvx4v9 and push.

[codeflash-ai]

This PR has been automatically closed because the original PR #419 by codeflash-ai[bot] was closed.