Benchmark: hui's test case for round

Script Preparation code:

var x = Math.random() * 100000000;
var y;

Tests:

round
y = Math.round(x)
>>
y = x > 0 ? (x + 0.5) >> 0 : (x - 0.5) >> 0;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
round
>>

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmarking test case.

**Overview**

The provided JSON represents a JavaScript microbenchmark that measures the performance of two different rounding algorithms: `Math.round()` and a custom implementation using bitwise shift operators (`>>`). The benchmark is designed to test how these algorithms perform on integers.

**Tested Options**

There are only two options being compared:

1. **`Math.round(x)`**: This is a built-in JavaScript function that rounds a number to the nearest integer.
2. **Custom implementation: `y = x > 0 ? (x + 0.5) >> 0 : (x - 0.5) >> 0;`**: This custom implementation uses bitwise shift operators to round a number to the nearest integer.

**Pros and Cons of Each Approach**

**1. Built-in `Math.round(x)`:**
	* Pros:
		+ Easy to implement and understand.
		+ Optimized for performance by the JavaScript engine.
	* Cons:
		+ May not be as efficient as a custom implementation, especially for large integers.

**2. Custom implementation:**
	* Pros:
		+ Can be optimized for specific use cases or hardware architectures.
		+ May provide better performance than the built-in function for certain inputs.
	* Cons:
		+ More complex and harder to understand, especially for those without experience with bitwise operations.
		+ Requires manual optimization and tuning.

**Additional Considerations**

The custom implementation uses a technique called "biasing" to round to the nearest even integer. This is done by adding or subtracting 0.5 to the input, depending on whether the number is positive or negative, and then shifting the result right by one bit. This approach can provide a consistent rounding behavior across different hardware architectures.

**Library Usage**

There are no libraries used in this benchmark.

**Special JS Features/Syntax**

The custom implementation uses bitwise shift operators (`>>`). The `>>` operator shifts the bits of its operand to the right and fills 0 on voids left as a result. This is a low-level operation that can provide performance benefits for certain use cases, but may not be suitable for all situations.

**Other Alternatives**

If you're interested in exploring alternative rounding algorithms or testing different JavaScript features, here are some options:

* Use a polyfill library like `mathjs` to test the custom implementation on older browsers.
* Experiment with different rounding modes, such as "round half to even" (e.g., `Math.round(x) = Math.trunc(x + 0.5)`).
* Test the performance of other rounding algorithms, such as "banker's rounding" or "round half up/down".
* Use a benchmarking framework like Jest or Mocha to write and run more comprehensive benchmarks.

Keep in mind that benchmarking is an art, and there's no one-size-fits-all solution. The choice of algorithm, implementation, and testing strategy depends on your specific use case and goals.

Related benchmarks:

hui's test case for round (version: 0)

Comparing performance of: round vs >>

Created: 2 years ago by: Guest

Jump to the latest result

round

>>

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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