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@codeflash-ai codeflash-ai bot commented Oct 28, 2025

📄 13% (0.13x) speedup for _check_value in optuna/pruners/_threshold.py

⏱️ Runtime : 3.56 milliseconds 3.14 milliseconds (best of 82 runs)

📝 Explanation and details

The optimized code achieves a 13% speedup through two key changes:

  1. Eliminates unnecessary variable assignment: The original code assigns value = float(value) then returns it later. The optimized version returns float(value) directly, removing the assignment overhead and reducing memory operations.

  2. Switches from .format() to f-string: The error message construction changes from "...{}...".format(type(value).__name__) to f"...{type(value).__name__}...". F-strings are faster because they're evaluated at compile-time rather than runtime, avoiding the method call overhead of .format().

The performance gains are most pronounced in error cases - test results show 15-31% improvements for invalid inputs (strings like "abc", None, complex numbers) where the TypeError path is taken. Valid numeric inputs show smaller but consistent gains of 5-25% due to the eliminated assignment.

These optimizations are particularly effective for:

  • High-error-rate scenarios where many invalid values trigger exceptions
  • Tight loops processing many values (as shown in the large-scale tests)
  • Mixed input validation where both valid and invalid cases occur frequently

The changes maintain identical functionality while reducing both CPU cycles and memory operations per function call.

Correctness verification report:

Test Status
⚙️ Existing Unit Tests 🔘 None Found
🌀 Generated Regression Tests 11175 Passed
⏪ Replay Tests 🔘 None Found
🔎 Concolic Coverage Tests 2 Passed
📊 Tests Coverage 100.0%
🌀 Generated Regression Tests and Runtime
from __future__ import annotations

from typing import Any

# imports
import pytest  # used for our unit tests
from optuna.pruners._threshold import _check_value

# unit tests

# 1. Basic Test Cases

def test_float_input():
    """Test that passing a float returns the same float."""
    codeflash_output = _check_value(3.14) # 534ns -> 345ns (54.8% faster)

def test_int_input():
    """Test that passing an int returns it as a float."""
    codeflash_output = _check_value(42) # 496ns -> 469ns (5.76% faster)

def test_string_float_input():
    """Test that passing a string representing a float returns the correct float."""
    codeflash_output = _check_value("2.718") # 930ns -> 878ns (5.92% faster)

def test_string_int_input():
    """Test that passing a string representing an int returns the correct float."""
    codeflash_output = _check_value("100") # 770ns -> 775ns (0.645% slower)

def test_string_with_spaces():
    """Test that passing a string with leading/trailing spaces is parsed correctly."""
    codeflash_output = _check_value("   5.5  ") # 813ns -> 693ns (17.3% faster)

def test_scientific_notation_string():
    """Test that passing a string in scientific notation returns the correct float."""
    codeflash_output = _check_value("1e3") # 909ns -> 905ns (0.442% faster)

def test_negative_number():
    """Test that negative numbers are handled correctly."""
    codeflash_output = _check_value(-7) # 534ns -> 497ns (7.44% faster)
    codeflash_output = _check_value("-8.5") # 634ns -> 657ns (3.50% slower)

# 2. Edge Test Cases

def test_zero():
    """Test that zero is handled correctly."""
    codeflash_output = _check_value(0) # 479ns -> 424ns (13.0% faster)
    codeflash_output = _check_value("0") # 546ns -> 491ns (11.2% faster)

def test_large_float():
    """Test a very large float value."""
    large = 1e308
    codeflash_output = _check_value(large) # 406ns -> 356ns (14.0% faster)
    codeflash_output = _check_value(str(large)) # 1.77μs -> 1.64μs (8.24% faster)

def test_small_float():
    """Test a very small float value."""
    small = 1e-308
    codeflash_output = _check_value(small) # 391ns -> 371ns (5.39% faster)
    codeflash_output = _check_value(str(small)) # 1.42μs -> 1.35μs (5.18% faster)

def test_nan():
    """Test that 'nan' string and float('nan') are handled correctly."""
    import math
    codeflash_output = _check_value(float('nan')); result = codeflash_output # 407ns -> 354ns (15.0% faster)
    codeflash_output = _check_value("nan"); result = codeflash_output # 389ns -> 386ns (0.777% faster)
    codeflash_output = _check_value("NaN"); result = codeflash_output # 218ns -> 220ns (0.909% slower)

def test_inf():
    """Test that 'inf' string and float('inf') are handled correctly."""
    import math
    codeflash_output = _check_value(float('inf')); result = codeflash_output # 390ns -> 346ns (12.7% faster)
    codeflash_output = _check_value("inf"); result = codeflash_output # 351ns -> 314ns (11.8% faster)
    codeflash_output = _check_value("-inf"); result = codeflash_output # 293ns -> 299ns (2.01% slower)

def test_invalid_string():
    """Test that a non-numeric string raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'str' but supposed to be a float."):
        _check_value("abc") # 3.75μs -> 3.11μs (20.5% faster)

def test_empty_string():
    """Test that an empty string raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'str' but supposed to be a float."):
        _check_value("") # 2.88μs -> 2.33μs (23.8% faster)

def test_none_input():
    """Test that None raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'NoneType' but supposed to be a float."):
        _check_value(None) # 2.93μs -> 2.48μs (18.2% faster)

def test_bool_input():
    """Test that boolean values are converted to float (True=1.0, False=0.0)."""
    codeflash_output = _check_value(True) # 633ns -> 539ns (17.4% faster)
    codeflash_output = _check_value(False) # 302ns -> 253ns (19.4% faster)

def test_list_input():
    """Test that a list raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'list' but supposed to be a float."):
        _check_value([1,2,3]) # 2.87μs -> 2.37μs (21.4% faster)

def test_dict_input():
    """Test that a dict raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'dict' but supposed to be a float."):
        _check_value({"a": 1}) # 2.78μs -> 2.36μs (17.5% faster)

def test_object_input():
    """Test that a generic object raises TypeError."""
    class Dummy:
        pass
    with pytest.raises(TypeError, match="The `value` argument is of type 'Dummy' but supposed to be a float."):
        _check_value(Dummy()) # 2.51μs -> 2.18μs (15.1% faster)


def test_complex_input():
    """Test that a complex number raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'complex' but supposed to be a float."):
        _check_value(1+2j) # 3.80μs -> 3.09μs (23.0% faster)

def test_string_with_comma():
    """Test that a string with comma as decimal separator raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'str' but supposed to be a float."):
        _check_value("1,23") # 3.25μs -> 2.89μs (12.7% faster)

def test_string_with_multiple_dots():
    """Test that a string with multiple dots raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'str' but supposed to be a float."):
        _check_value("1.2.3") # 2.93μs -> 2.48μs (18.4% faster)

def test_string_with_letters_and_numbers():
    """Test that a string with mixed letters and numbers raises TypeError."""
    with pytest.raises(TypeError, match="The `value` argument is of type 'str' but supposed to be a float."):
        _check_value("123abc") # 2.73μs -> 2.29μs (19.2% faster)


def test_large_list_of_valid_values():
    """Test many valid numeric inputs in a list."""
    for i in range(1000):
        codeflash_output = _check_value(i) # 147μs -> 137μs (7.41% faster)
        codeflash_output = _check_value(str(i))
        codeflash_output = _check_value(float(i)) # 185μs -> 173μs (6.80% faster)

def test_large_list_of_invalid_strings():
    """Test that many invalid strings all raise TypeError."""
    for i in range(1000):
        with pytest.raises(TypeError):
            _check_value(f"foo{i}")

def test_performance_on_large_numbers():
    """Test that very large and very small numbers are handled efficiently."""
    # Not a strict performance test, but ensures no overflow or crash
    large_numbers = [1e308, -1e308, 1e-308, -1e-308]
    for num in large_numbers:
        codeflash_output = _check_value(num) # 1.12μs -> 979ns (14.4% faster)
        codeflash_output = _check_value(str(num))

def test_large_number_of_edge_cases():
    """Test a mix of valid and invalid cases in a large batch."""
    valid_inputs = [str(i) for i in range(500)]
    invalid_inputs = [f"x{i}" for i in range(500)]
    for v in valid_inputs:
        codeflash_output = _check_value(v) # 92.2μs -> 86.5μs (6.52% faster)
    for v in invalid_inputs:
        with pytest.raises(TypeError):
            _check_value(v)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
from __future__ import annotations

from typing import Any

# imports
import pytest  # used for our unit tests
from optuna.pruners._threshold import _check_value

# unit tests

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

def test_check_value_with_float():
    # Should accept float and return the same value
    codeflash_output = _check_value(1.23) # 577ns -> 625ns (7.68% slower)

def test_check_value_with_int():
    # Should accept int and return float of the value
    codeflash_output = _check_value(42) # 647ns -> 544ns (18.9% faster)

def test_check_value_with_str_float():
    # Should accept string representing a float
    codeflash_output = _check_value("3.1415") # 932ns -> 970ns (3.92% slower)

def test_check_value_with_str_int():
    # Should accept string representing an int
    codeflash_output = _check_value("100") # 778ns -> 770ns (1.04% faster)

def test_check_value_with_negative_number():
    # Should handle negative numbers
    codeflash_output = _check_value(-7) # 504ns -> 469ns (7.46% faster)

def test_check_value_with_str_negative_number():
    # Should handle negative number strings
    codeflash_output = _check_value("-8.8") # 931ns -> 882ns (5.56% faster)

def test_check_value_with_zero():
    # Should handle zero
    codeflash_output = _check_value(0) # 542ns -> 432ns (25.5% faster)

def test_check_value_with_str_zero():
    # Should handle string zero
    codeflash_output = _check_value("0") # 747ns -> 710ns (5.21% faster)

def test_check_value_with_float_scientific_notation():
    # Should handle scientific notation
    codeflash_output = _check_value("1e3") # 945ns -> 915ns (3.28% faster)
    codeflash_output = _check_value(1e-3) # 271ns -> 239ns (13.4% faster)

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

def test_check_value_with_empty_string():
    # Should raise TypeError for empty string
    with pytest.raises(TypeError) as excinfo:
        _check_value("") # 3.69μs -> 2.81μs (31.1% faster)

def test_check_value_with_none():
    # Should raise TypeError for None
    with pytest.raises(TypeError) as excinfo:
        _check_value(None) # 3.14μs -> 2.51μs (24.7% faster)

def test_check_value_with_bool_true():
    # Should accept bool and return 1.0
    codeflash_output = _check_value(True) # 590ns -> 545ns (8.26% faster)

def test_check_value_with_bool_false():
    # Should accept bool and return 0.0
    codeflash_output = _check_value(False) # 490ns -> 437ns (12.1% faster)

def test_check_value_with_invalid_str():
    # Should raise TypeError for non-numeric string
    with pytest.raises(TypeError) as excinfo:
        _check_value("hello") # 3.54μs -> 3.00μs (18.3% faster)

def test_check_value_with_list():
    # Should raise TypeError for list input
    with pytest.raises(TypeError) as excinfo:
        _check_value([1,2,3]) # 2.81μs -> 2.35μs (19.8% faster)

def test_check_value_with_dict():
    # Should raise TypeError for dict input
    with pytest.raises(TypeError) as excinfo:
        _check_value({'a':1}) # 2.79μs -> 2.33μs (19.9% faster)

def test_check_value_with_tuple():
    # Should raise TypeError for tuple input
    with pytest.raises(TypeError) as excinfo:
        _check_value((1,2)) # 2.72μs -> 2.21μs (22.8% faster)

def test_check_value_with_object():
    # Should raise TypeError for arbitrary object
    class Foo: pass
    with pytest.raises(TypeError) as excinfo:
        _check_value(Foo()) # 2.49μs -> 2.08μs (19.6% faster)

def test_check_value_with_nan_and_inf():
    # Should accept float('nan') and float('inf')
    import math
    nan = float('nan')
    inf = float('inf')
    codeflash_output = _check_value(inf) # 447ns -> 428ns (4.44% faster)
    codeflash_output = _check_value("-inf") # 484ns -> 493ns (1.83% slower)

def test_check_value_with_str_nan_inf():
    # Should accept string 'nan', 'inf', '-inf'
    import math
    codeflash_output = _check_value("inf") # 662ns -> 615ns (7.64% faster)
    codeflash_output = _check_value("-inf") # 323ns -> 289ns (11.8% faster)


def test_check_value_with_complex():
    # Should raise TypeError for complex input
    with pytest.raises(TypeError) as excinfo:
        _check_value(1+2j) # 3.90μs -> 3.05μs (27.7% faster)

def test_check_value_with_str_with_spaces():
    # Should accept string with leading/trailing spaces
    codeflash_output = _check_value("  42.5  ") # 1.04μs -> 977ns (6.35% faster)


def test_check_value_with_str_with_comma():
    # Should raise TypeError for string with comma
    with pytest.raises(TypeError) as excinfo:
        _check_value("1,000") # 3.87μs -> 2.95μs (31.1% faster)

def test_check_value_with_str_with_multiple_dots():
    # Should raise TypeError for string with multiple dots
    with pytest.raises(TypeError) as excinfo:
        _check_value("1.2.3") # 3.06μs -> 2.43μs (26.1% faster)

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

def test_check_value_large_list_of_valid_numbers():
    # Should process many valid numbers without error
    for i in range(1000):
        codeflash_output = _check_value(i) # 145μs -> 140μs (3.85% faster)
        codeflash_output = _check_value(str(i))

def test_check_value_large_list_of_invalid_strings():
    # Should raise TypeError for many invalid strings
    for i in range(1000):
        with pytest.raises(TypeError):
            _check_value(f"not_a_number_{i}")

def test_check_value_large_list_of_floats():
    # Should process many floats, including negatives
    for i in range(-500, 500):
        val = i / 10.0
        codeflash_output = _check_value(val) # 141μs -> 138μs (2.77% faster)
        codeflash_output = _check_value(str(val))

def test_check_value_large_list_of_edge_values():
    # Should handle edge float values
    import sys
    values = [sys.float_info.max, sys.float_info.min, -sys.float_info.max, -sys.float_info.min]
    for v in values:
        codeflash_output = _check_value(v) # 959ns -> 948ns (1.16% faster)
        codeflash_output = _check_value(str(v))

def test_check_value_large_list_of_booleans():
    # Should handle many booleans
    for i in range(500):
        codeflash_output = _check_value(True) # 73.6μs -> 71.1μs (3.52% faster)
        codeflash_output = _check_value(False)

def test_check_value_large_list_of_none():
    # Should raise TypeError for many None values
    for _ in range(100):
        with pytest.raises(TypeError):
            _check_value(None)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
from optuna.pruners._threshold import _check_value
import pytest

def test__check_value():
    with pytest.raises(TypeError, match="The\\ `value`\\ argument\\ is\\ of\\ type\\ 'str'\\ but\\ supposed\\ to\\ be\\ a\\ float\\."):
        _check_value('')

def test__check_value_2():
    _check_value(0)
🔎 Concolic Coverage Tests and Runtime
Test File::Test Function Original ⏱️ Optimized ⏱️ Speedup
codeflash_concolic_wou29s7s/tmpb8biv61w/test_concolic_coverage.py::test__check_value 2.97μs 2.61μs 13.8%✅
codeflash_concolic_wou29s7s/tmpb8biv61w/test_concolic_coverage.py::test__check_value_2 566ns 475ns 19.2%✅

To edit these changes git checkout codeflash/optimize-_check_value-mhaz7y6m and push.

Codeflash

The optimized code achieves a **13% speedup** through two key changes:

1. **Eliminates unnecessary variable assignment**: The original code assigns `value = float(value)` then returns it later. The optimized version returns `float(value)` directly, removing the assignment overhead and reducing memory operations.

2. **Switches from `.format()` to f-string**: The error message construction changes from `"...{}...".format(type(value).__name__)` to `f"...{type(value).__name__}..."`. F-strings are faster because they're evaluated at compile-time rather than runtime, avoiding the method call overhead of `.format()`.

The performance gains are most pronounced in error cases - test results show **15-31% improvements** for invalid inputs (strings like "abc", None, complex numbers) where the TypeError path is taken. Valid numeric inputs show smaller but consistent gains of **5-25%** due to the eliminated assignment.

These optimizations are particularly effective for:
- **High-error-rate scenarios** where many invalid values trigger exceptions
- **Tight loops** processing many values (as shown in the large-scale tests)
- **Mixed input validation** where both valid and invalid cases occur frequently

The changes maintain identical functionality while reducing both CPU cycles and memory operations per function call.
@codeflash-ai codeflash-ai bot requested a review from mashraf-222 October 28, 2025 19:45
@codeflash-ai codeflash-ai bot added ⚡️ codeflash Optimization PR opened by Codeflash AI 🎯 Quality: High Optimization Quality according to Codeflash labels Oct 28, 2025
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