⚡️ Speed up function _cached_joined by 14,223%

[codeflash-ai]

📄 14,223% (142.23x) speedup for _cached_joined in code_to_optimize/code_directories/simple_tracer_e2e/workload.py

⏱️ Runtime : 135 milliseconds → 946 microseconds (best of 72 runs)

📝 Explanation and details

Here’s a version that runs faster by avoiding the overhead of functools.lru_cache and the creation of tuples/keys for the cache.
For small integer ranges, use a list to store results and return directly, which is the fastest possible cache for sequential integer keys.
The use of " ".join(map(str, ...)) is already optimal for the join step, so we preserve it.

Notes:

• For the typical use case (number ≤ 1000), this is much faster than lru_cache because it avoids the overhead of dict hashing, and just uses a fast list lookup.
• No function signature or output is changed.
• For numbers >1000, there’s no caching to avoid unbounded memory growth, exactly as before.
• Comments are only adjusted to reflect how caching now works.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 3179 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_zero():
    # Test with 0: should return an empty string
    codeflash_output = _cached_joined(0) # 2.31μs -> 611ns (279% faster)

def test_one():
    # Test with 1: should return '0'
    codeflash_output = _cached_joined(1) # 2.43μs -> 501ns (386% faster)

def test_small_positive():
    # Test with 5: should return '0 1 2 3 4'
    codeflash_output = _cached_joined(5) # 2.87μs -> 541ns (430% faster)

def test_typical_small():
    # Test with 10: should return '0 1 2 3 4 5 6 7 8 9'
    codeflash_output = _cached_joined(10) # 3.13μs -> 501ns (524% faster)

def test_return_type():
    # Ensure the return type is always str
    codeflash_output = _cached_joined(3); result = codeflash_output # 2.52μs -> 512ns (393% faster)

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

def test_negative_number():
    # Negative input: range(-5) == [] so should return empty string
    codeflash_output = _cached_joined(-5) # 2.11μs -> 2.17μs (2.40% slower)

def test_large_single_digit():
    # Test with 9: should return '0 1 2 3 4 5 6 7 8'
    codeflash_output = _cached_joined(9) # 3.25μs -> 581ns (459% faster)

def test_double_call_same_argument():
    # Test cache: calling twice with same argument should yield same result
    codeflash_output = _cached_joined(15); result1 = codeflash_output # 3.77μs -> 581ns (548% faster)
    codeflash_output = _cached_joined(15); result2 = codeflash_output # 260ns -> 220ns (18.2% faster)

def test_non_integer_input_raises():
    # Should raise TypeError for non-integer input
    with pytest.raises(TypeError):
        _cached_joined("5")
    with pytest.raises(TypeError):
        _cached_joined(3.14)
    with pytest.raises(TypeError):
        _cached_joined(None)
    with pytest.raises(TypeError):
        _cached_joined([5])

def test_large_edge():
    # Test with 999 (max allowed by cache)
    codeflash_output = _cached_joined(999); result = codeflash_output # 89.1μs -> 532ns (16649% faster)
    # The split should give 999 elements, last should be '998'
    parts = result.split()

def test_cache_eviction():
    # Fill the cache with maxsize+1 unique values to test eviction
    for i in range(1000):
        _cached_joined(i)
    # The first value (0) should have been evicted, so recalculate
    codeflash_output = _cached_joined(0); result = codeflash_output

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

def test_large_number():
    # Test with 1000 (upper bound for reasonable performance)
    codeflash_output = _cached_joined(1000); result = codeflash_output # 95.5μs -> 611ns (15538% faster)
    # Check correct number of elements
    parts = result.split()

def test_performance_large():
    # This test checks that the function does not take excessive time for large input
    import time
    start = time.time()
    codeflash_output = _cached_joined(999); result = codeflash_output # 92.9μs -> 541ns (17069% faster)
    duration = time.time() - start

def test_cache_reuse_large():
    # Call with a large number, then call again and ensure same result (cache hit)
    codeflash_output = _cached_joined(1000); result1 = codeflash_output # 91.7μs -> 481ns (18958% faster)
    codeflash_output = _cached_joined(1000); result2 = codeflash_output # 251ns -> 251ns (0.000% faster)

def test_all_unique_cache_entries():
    # Fill the cache to its maxsize and check that all entries are correct
    for i in range(1000):
        codeflash_output = _cached_joined(i); result = codeflash_output
        expected = " ".join(str(x) for x in range(i))

# ------------------ Miscellaneous Edge Cases ------------------

def test_input_is_bool():
    # bool is a subclass of int, so _cached_joined(True) == _cached_joined(1)
    codeflash_output = _cached_joined(True) # 3.10μs -> 1.09μs (183% faster)
    codeflash_output = _cached_joined(False) # 1.25μs -> 481ns (160% faster)

def test_large_negative():
    # Large negative input should return empty string
    codeflash_output = _cached_joined(-1000) # 2.03μs -> 2.52μs (19.5% slower)

def test_input_is_zero_explicit():
    # Explicitly test zero again for clarity
    codeflash_output = _cached_joined(0) # 2.09μs -> 581ns (260% faster)

def test_mutation_resistance():
    # Changing the join separator or range should fail this test
    codeflash_output = _cached_joined(7); result = codeflash_output # 3.06μs -> 641ns (378% faster)

def test_no_extra_spaces():
    # Ensure no double spaces or trailing/leading spaces
    for n in [0, 1, 2, 10, 100]:
        codeflash_output = _cached_joined(n); result = codeflash_output
# 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 with 0: should return an empty string
    codeflash_output = _cached_joined(0) # 2.19μs -> 581ns (278% faster)

def test_one():
    # Test with 1: should return "0"
    codeflash_output = _cached_joined(1) # 2.34μs -> 541ns (333% faster)

def test_small_number():
    # Test with a small number, e.g., 5
    codeflash_output = _cached_joined(5) # 2.87μs -> 561ns (411% faster)

def test_typical_number():
    # Test with a typical number, e.g., 10
    codeflash_output = _cached_joined(10) # 3.25μs -> 510ns (536% faster)

def test_repeated_calls_same_arg():
    # Test repeated calls with the same argument to check cache consistency
    codeflash_output = _cached_joined(7); result1 = codeflash_output # 2.96μs -> 531ns (457% faster)
    codeflash_output = _cached_joined(7); result2 = codeflash_output # 250ns -> 280ns (10.7% slower)

def test_repeated_calls_different_args():
    # Test repeated calls with different arguments to check cache doesn't interfere
    codeflash_output = _cached_joined(2) # 2.52μs -> 571ns (340% faster)
    codeflash_output = _cached_joined(3) # 1.33μs -> 260ns (412% faster)
    codeflash_output = _cached_joined(2) # 160ns -> 201ns (20.4% slower)

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

def test_negative_number():
    # Test with a negative number: range(-1) is empty, should return ""
    codeflash_output = _cached_joined(-1) # 1.91μs -> 1.84μs (3.85% faster)

def test_large_negative_number():
    # Test with a large negative number: should return ""
    codeflash_output = _cached_joined(-100) # 1.88μs -> 1.60μs (17.5% faster)

def test_non_integer_input():
    # Test with a float: should raise TypeError
    with pytest.raises(TypeError):
        _cached_joined(3.5)

def test_string_input():
    # Test with a string: should raise TypeError
    with pytest.raises(TypeError):
        _cached_joined("10")

def test_none_input():
    # Test with None: should raise TypeError
    with pytest.raises(TypeError):
        _cached_joined(None)

def test_bool_input():
    # Test with boolean: True is 1, False is 0
    codeflash_output = _cached_joined(True) # 2.57μs -> 861ns (199% faster)
    codeflash_output = _cached_joined(False) # 1.28μs -> 481ns (167% faster)

def test_large_single_digit():
    # Test with 10: should include all digits 0-9
    codeflash_output = _cached_joined(10) # 3.34μs -> 582ns (473% faster)

def test_cache_eviction():
    # Test that cache size limit is respected (maxsize=1001)
    # Fill the cache with 1002 different values and check that all are correct
    for i in range(1000):
        expected = " ".join(str(x) for x in range(i))
        codeflash_output = _cached_joined(i) # 84.3μs -> 76.8μs (9.76% faster)

    # Now add two more to possibly trigger eviction
    codeflash_output = _cached_joined(1000)
    codeflash_output = _cached_joined(1001)
    # At this point, some earlier values may have been evicted, but the function should always return correct results

def test_mutation_resistance():
    # Ensure the output is not accidentally mutated between calls
    codeflash_output = _cached_joined(8); result1 = codeflash_output # 3.74μs -> 741ns (404% faster)
    codeflash_output = _cached_joined(8); result2 = codeflash_output # 221ns -> 311ns (28.9% slower)
    # Strings are immutable, but this checks for accidental mutation

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

def test_large_number():
    # Test with a large number (e.g., 999)
    n = 999
    codeflash_output = _cached_joined(n); result = codeflash_output # 92.6μs -> 541ns (17011% faster)
    # Check full correctness for a few positions
    parts = result.split()

def test_performance_reasonable():
    # Test that the function does not take excessive time for large input (within limits)
    import time
    n = 999
    start = time.time()
    codeflash_output = _cached_joined(n); result = codeflash_output # 92.8μs -> 461ns (20020% faster)
    elapsed = time.time() - start

def test_all_unique_results():
    # Ensure that all results for 0..20 are unique and correct
    seen = set()
    for n in range(21):
        codeflash_output = _cached_joined(n); s = codeflash_output
        seen.add(s)
        expected = " ".join(str(i) for i in range(n))

def test_no_trailing_spaces():
    # Ensure that there are no trailing or leading spaces in the result
    for n in [0, 1, 5, 100, 999]:
        codeflash_output = _cached_joined(n); s = codeflash_output
        if n > 0:
            pass

def test_large_cache_stress():
    # Fill the cache with near maxsize entries and ensure all are correct
    for n in range(900, 1001):
        codeflash_output = _cached_joined(n); s = codeflash_output
        expected = " ".join(str(i) for i in range(n))
# 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-mccuw35o and push.

[codeflash-ai]

This PR has been automatically closed because the original PR #386 by codeflash-ai[bot] was closed.