Benchmark: Fast atan2 vs Math.atan2

Script Preparation code:

const abs = Math.abs, min = Math.min, max = Math.max, PI = Math.PI, PI2 = PI / 2;
    var fatan2 = (y, x) => {
         const ax = abs(x);
         const ay = abs(y);
         const a = min(ax, ay) / max(x, y);
         const s = a * a;
         let r = ((-0.0464964749 * s + 0.15931422) * s - 0.327622764) * s * a + a;
         if (ay > ax) r = PI2 - r;
         if (x < 0) r = PI - r;
         if (y < 0) r = -r;
         return r;
    };
    var atan2 = Math.atan2;
var random = Math.random;

Tests:

atan2
var k = atan2(random());
fast atan2
var k = fatan2(random());

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
atan2
fast atan2

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

The provided JSON represents two JavaScript microbenchmarks: `atan2` and `fast atan2`. The first benchmark tests the standard `Math.atan2()` function, while the second benchmark tests a custom implementation of `atan2`, denoted as `fatan2`.

**What is tested on the provided JSON?**

The JSON test cases are designed to measure the performance difference between the standard `Math.atan2()` function and the custom `fatan2` implementation. The test cases use JavaScript's built-in `Math.random()` function to generate random inputs for the `atan2()` function.

**Options compared**

There are two options being compared:

1. **Standard Math.atan2()**: This is the standard implementation of the `atan2()` function provided by JavaScript.
2. **Custom fatan2 implementation**: This is a custom implementation of the `atan2()` function written in the provided script preparation code.

**Pros and Cons**

**Standard Math.atan2():**

Pros:

* Widely supported and well-maintained by the ECMAScript standard.
* Likely to be optimized for performance by most JavaScript engines.

Cons:

* May not be as fast as custom implementations, especially for specific use cases.
* Limited control over optimization and caching.

**Custom fatan2 implementation:**

Pros:

* Can be highly optimized for specific use cases or platforms.
* Allows for fine-grained control over optimization and caching.

Cons:

* May require more effort to maintain and update.
* May not be as widely supported or well-maintained as the standard `Math.atan2()` function.

**Other considerations**

The custom `fatan2` implementation uses a few tricks to achieve its performance gains, including:

* Using absolute values to reduce branch prediction errors.
* Implementing a lookup table for the `r` calculation.
* Using a more efficient algorithm for calculating the `a` value.

However, these optimizations may come at the cost of increased complexity and maintenance effort.

**Library and purpose**

The `Math.random()` function is a built-in JavaScript library that generates random numbers. It is used in both test cases to generate random inputs for the `atan2()` function.

**Special JS feature or syntax**

There are no special JavaScript features or syntaxes being tested in these benchmarks. The focus is on measuring the performance difference between two implementations of the same function.

Overall, these benchmarks provide a useful comparison between a standard implementation and a custom optimization of the `atan2()` function, allowing developers to evaluate the trade-offs between performance, maintainability, and complexity.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.4972.0 Safari/537.36

Browser/OS: Chrome 102 on Windows

View result in a separate tab

Test name	Executions per second
atan2	6046074.5 Ops/sec
fast atan2	5949697.5 Ops/sec

Related benchmarks:

Fast atan2 vs Math.atan2 (version: 0)

Comparing performance of: atan2 vs fast atan2

Created: 2 years ago by: Guest

Jump to the latest result

atan2

fast atan2

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):