Benchmark: fast square roo - MeasureThat.net

Script Preparation code:

var i;
var r;
var v = 2**16;

function test1() {
  for(i=0; i < 1000; ++i) {
    r = getTheMiddle(v);
  }
}

function test2() {
  for(i=0; i < 1000; ++i) {
    r = Q_rsqrt(v) * v;
  }
}
function getTheMiddle(number){
  var start = 0;
  var end = number;
  var theMiddle = (start+end)/2;
  while (Math.abs(theMiddle*theMiddle - number) > 0.00001)
     {
         if (theMiddle*theMiddle > number)
         {
             end = theMiddle;
         }
         else
         {
             start = theMiddle;
         }
                
         theMiddle = (start+end)/2;
         return theMiddle;
    }
}
//Based on the fast inverse square root function
// https://en.wikipedia.org/wiki/Fast_inverse_square_root
// Some original comments preserved for humor value
// Designed to try to mimic the original as closely as possible
function Q_rsqrt(number)
{ 
    var i;
    var x2, y;
    const threehalfs = 1.5;
  
    x2 = number * 0.5;
    y = number;
    //evil floating bit level hacking
    var buf = new ArrayBuffer(4);
    (new Float32Array(buf))[0] = number;
    i =  (new Uint32Array(buf))[0];
    i = (0x5f3759df - (i >> 1)); //What the fuck?
    (new Uint32Array(buf))[0] = i;
    y = (new Float32Array(buf))[0];
    y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration
//  y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

    return y;
}

Tests:

the middle
test1();
fisqrt
test2();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
the middle
fisqrt

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested on the provided JSON.

**Benchmark Test**

The benchmark test is designed to measure the performance of two different approaches for calculating the middle value of a large number. The benchmark is named "fast square root" and consists of two individual test cases: "the middle" and "fisqrt".

**Approaches Compared**

The two approaches being compared are:

1. **Manual implementation**: This approach uses a custom function `getTheMiddle` to calculate the middle value. The function iteratively updates its bounds until it finds the exact middle value.
2. **Fast inverse square root (FISRT) library**: This approach uses a pre-written library function `Q_rsqrt` to calculate the inverse square root of a number.

**Pros and Cons**

**Manual implementation:**

Pros:

* Control over the implementation
* Can be optimized for specific use cases

Cons:

* More complex code
* May not be as efficient as specialized libraries

**FISRT library:**

Pros:

* Highly optimized for performance
* Provides a reliable and accurate result

Cons:

* Requires an external library (which may have dependencies)
* Limited control over the implementation

**Other Considerations**

The benchmark also takes into account the device platform, operating system, and browser version used to run the test. This helps to isolate any platform or browser-specific issues.

**Library: FISRT Library**

The `Q_rsqrt` function in the benchmark is an implementation of the fast inverse square root algorithm from Wikipedia. The library provides a pre-written function for calculating the inverse square root, which is optimized for performance.

**Special JS Features**

There are no special JavaScript features or syntax used in this benchmark that require explanation.

**Alternatives**

If you want to run similar benchmarks, here are some alternatives:

1. **Benchmark.js**: A popular benchmarking library for JavaScript.
2. **Benchmark suite**: A set of benchmarking tools for JavaScript and other languages.
3. **Google Benchmark**: A high-performance benchmarking framework for C++ and other languages (with a JavaScript wrapper available).

Keep in mind that the specific alternatives will depend on your needs and goals, but these options are widely used and well-regarded in the industry.

Related benchmarks:

fast square roo (version: 1)

Comparing performance of: the middle vs fisqrt

Created: 5 years ago by: Registered User

Jump to the latest result

the middle

fisqrt

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):