⚡️ Speed up function manga by 508%

[codeflash-ai]

📄 508% (5.08x) speedup for manga in src/async_examples/concurrency.py

⏱️ Runtime : 1.68 minutes → 16.6 seconds (best of 24 runs)

📝 Explanation and details

The optimization replaces sum(range(100000)) with the mathematical formula (100000 * 99999) // 2, which eliminates the most expensive operation in the code.

Key Change:

• Arithmetic sequence formula: Instead of creating a 100,000-element range object and iterating through it to compute the sum, the optimized version uses the direct mathematical formula for summing consecutive integers from 0 to n-1: n*(n-1)//2.

Why This Speeds Up Performance:

• Eliminates O(n) iteration: The original sum(range(100000)) creates a range object and iterates through 100,000 numbers, performing 100,000 addition operations
• Reduces to O(1) calculation: The formula performs just two multiplication operations and one integer division
• Eliminates memory allocation: No range object creation means significantly less memory pressure

Performance Impact:
From the line profiler results, the sum calculation went from consuming 89.8% of total runtime (2.7 billion nanoseconds) to just 0.3% (568,000 nanoseconds) - a ~4,760x improvement on this specific line. This single change accounts for the overall 508% speedup.

Test Case Performance:
The optimization is particularly effective for test cases that run manga() multiple times concurrently (like test_manga_concurrent_execution and test_manga_large_scale_concurrent), as it eliminates the computational bottleneck that would otherwise scale linearly with the number of concurrent tasks.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 240 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

import asyncio  # used to run async functions
import time

import pytest  # used for our unit tests
from src.async_examples.concurrency import manga

# --- Unit Tests ---

# 1. Basic Test Cases

@pytest.mark.asyncio
async def test_manga_returns_expected_length():
    """Test that manga returns 10 results (5 async, 5 sync)."""
    result = await manga()

@pytest.mark.asyncio
async def test_manga_content_format():
    """Test that manga returns results in expected format."""
    result = await manga()
    # Check alternating pattern of async and sync results
    for i in range(5):
        pass

@pytest.mark.asyncio
async def test_manga_async_behavior():
    """Test that manga is truly asynchronous by timing execution."""
    start = time.time()
    result = await manga()
    end = time.time()

# 2. Edge Test Cases

@pytest.mark.asyncio
async def test_manga_concurrent_execution():
    """Test concurrent execution of multiple manga calls."""
    # Run 3 manga calls concurrently
    tasks = [manga() for _ in range(3)]
    results = await asyncio.gather(*tasks)
    # Each result should be a list of 10 elements
    for result in results:
        pass

@pytest.mark.asyncio
async def test_manga_cancellation():
    """Test that manga can be cancelled during execution."""
    task = asyncio.create_task(manga())
    await asyncio.sleep(0.0002)  # Let it start
    task.cancel()
    try:
        await task
    except asyncio.CancelledError:
        pass  # Expected

@pytest.mark.asyncio
async 
#------------------------------------------------
import asyncio  # used to run async functions
import time

import pytest  # used for our unit tests
from src.async_examples.concurrency import manga

# unit tests

@pytest.mark.asyncio
async def test_manga_basic_structure():
    """Test that manga returns a list of 10 items, alternating async/sync results."""
    result = await manga()
    # Check alternating pattern
    for i in range(5):
        pass

@pytest.mark.asyncio
async def test_manga_basic_content():
    """Test that manga returns correct processed values for async and sync tasks."""
    result = await manga()
    # Check that the sum is correct
    expected_sum = sum(range(1000))
    for i in range(5):
        pass

@pytest.mark.asyncio
async def test_manga_is_async():
    """Test that manga is an async coroutine and must be awaited."""
    # The function should return a coroutine when called
    codeflash_output = manga(); coro = codeflash_output
    result = await coro

@pytest.mark.asyncio
async def test_manga_concurrent_execution():
    """Test concurrent execution of manga using asyncio.gather."""
    # Run manga concurrently 5 times
    tasks = [manga() for _ in range(5)]
    results = await asyncio.gather(*tasks)
    # Each result should be correct and independent
    for result in results:
        for i in range(5):
            pass

@pytest.mark.asyncio
async def test_manga_exception_handling():
    """Test that manga propagates exceptions from fake_api_call."""
    # Patch fake_api_call to raise exception for a specific case
    async def fake_api_call_exception(delay, data):
        if data == "async_2":
            raise ValueError("API call failed")
        await asyncio.sleep(0.0001)
        return f"Processed: {data}"

    # Monkeypatch manga to use the exception-raising fake_api_call
    async def manga_with_exception():
        results = []
        for i in range(5):
            async_result = await fake_api_call_exception(0.3, f"async_{i}")
            results.append(async_result)
            time.sleep(0.0001)
            summer = sum(range(1000))
            results.append(f"Sync task {i} completed with sum: {summer}")
        return results

    with pytest.raises(ValueError, match="API call failed"):
        await manga_with_exception()

@pytest.mark.asyncio
async def test_manga_cancellation():
    """Test that manga can be cancelled during execution."""
    # Start manga in a task
    task = asyncio.create_task(manga())
    # Cancel after a short delay
    await asyncio.sleep(0.00005)
    task.cancel()
    try:
        await task
    except asyncio.CancelledError:
        pass  # Expected: cancellation should raise CancelledError
    else:
        raise AssertionError("Cancelled manga task did not raise CancelledError")

@pytest.mark.asyncio
async def test_manga_large_scale_concurrent():
    """Test manga's behavior under large concurrent load (up to 50 tasks)."""
    # Run 50 concurrent manga tasks
    num_tasks = 50
    tasks = [manga() for _ in range(num_tasks)]
    results = await asyncio.gather(*tasks)
    for result in results:
        pass

@pytest.mark.asyncio
async def test_manga_performance_under_load():
    """Test that manga completes all tasks within reasonable time under concurrent load."""
    num_tasks = 20
    start = time.time()
    results = await asyncio.gather(*(manga() for _ in range(num_tasks)))
    duration = time.time() - start
    # Check results are correct
    for result in results:
        pass

@pytest.mark.asyncio
async def test_manga_async_iterator_pattern():
    """Test that manga can be run in an async iterator context if wrapped."""
    # Wrap manga in an async generator for demonstration
    async def manga_gen():
        result = await manga()
        for item in result:
            yield item

    items = []
    async for x in manga_gen():
        items.append(x)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
from src.async_examples.concurrency import manga

To edit these changes git checkout codeflash/optimize-manga-mez22jsi and push.