Benchmark: clamp vs bitClamp

Script Preparation code:

window.clamp = (val, min, max) => val < min ? min : val > max ? max : val;
window.bitClamp = (x, min, max) => {
  x = x - ((x - max) & ((max - x) >> 31));
  return x - ((x - min) & ((x - min) >> 31));
}

Tests:

clamp
clamp(Math.random() * 100000000000000000, 52, 896987565547);
bitClamp
bitClamp(Math.random() * 100000000000000000, 52, 896987565547);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
clamp
bitClamp

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36

Browser/OS: Chrome 144 on Windows

View result in a separate tab

Test name	Executions per second
clamp	34435296.0 Ops/sec
bitClamp	34294036.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmarked Functionality:**
The two benchmarked functions are `clamp` and `bitClamp`, which both take three arguments: `val`, `min`, and `max`. The purpose of these functions is to clamp a value within a specified range. Clamping means limiting the value to be within a certain range, preventing it from going below the minimum or above the maximum.

**clamp Function:**
The `clamp` function is implemented as a simple conditional statement:
```javascript
window.clamp = (val, min, max) => val < min ? min : val > max ? max : val;
```
This implementation checks if the value is less than the minimum or greater than the maximum. If it's within the range, the original value is returned.

**bitClamp Function:**
The `bitClamp` function uses a clever trick to clamp the value without using conditional statements:
```javascript
window.bitClamp = (x, min, max) => {
  x = x - ((x - max) & ((max - x) >> 31));
  return x - ((x - min) & ((x - min) >> 31));
};
```
This implementation uses bitwise operations to "fold" the value onto a smaller range. It subtracts the difference between the current value and the maximum, effectively "mirroring" the value across the maximum boundary. The result is then adjusted by subtracting the difference between the current value and the minimum.

**Comparison:**
The benchmark compares the performance of `clamp` and `bitClamp`. Both functions have their pros and cons:

*   **clamp:** Pros:
    *   Easy to understand and implement.
    *   Less computationally expensive due to its simple conditional statement.
*   **Cons:**

*   May be slower for very large or small input values due to the extra comparisons.
*   **bitClamp:** Pros:
    *   More efficient, as it avoids unnecessary comparisons.
    *   Potentially faster for a wide range of input values.

However, `bitClamp` also has some cons:

*   More complex implementation with bitwise operations.
*   May have performance issues if not implemented correctly or on certain hardware architectures.

**Other Considerations:**

*   Both functions should work well for most use cases where the input value is within a reasonable range (e.g., between 0 and 1).
*   For extremely large or small values, `clamp` might be more suitable to avoid potential issues with `bitClamp`.

The benchmark result shows that `bitClamp` performs slightly better on this specific test case.

**Alternative Implementations:**
Other possible implementations could include:

*   Using arithmetic operations (e.g., `Math.max` and `Math.min`) instead of bitwise operations.
*   Employing a lookup table or interpolation method for clamping values within a large range.
*   Utilizing hardware features like SIMD instructions to accelerate the calculations.

Keep in mind that each alternative implementation will have its own trade-offs in terms of performance, readability, and maintainability.

Related benchmarks:

clamp vs bitClamp (version: 0)

Comparing performance of: clamp vs bitClamp

Created: 2 years ago by: Registered User

Jump to the latest result

clamp

bitClamp

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):