Benchmark: Math.sqrt() vs Fast inverse sqrt

Script Preparation code:

let v = 123.75;

function test1() {
  let r;
  for(let i = 0; i < 2000; ++i)
    r = 1 / Math.sqrt(v);
}

function test2() {
  let r;
  for(let i = 0; i < 2000; ++i)
    r = Q_sqrt(v);
}

function Q_sqrt(num) {
  let i = [];
  let y = [];
  
  y[0] = num;
  i[0] = 0x5f375a86 - (i[0] >> 1);
  
  y[0] = y[0] * (1.5 * ((num * 0.5) * y[0] * y[0]));
  
  return y[0];
}

Tests:

1 / Math.sqrt()
test1();
Fast inverse sqrt
test2();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
1 / Math.sqrt()
Fast inverse sqrt

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 4 months ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 16_7 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/119.0.6045.169 Mobile/15E148 Safari/604.1

Browser/OS: Chrome Mobile iOS 119 on iOS 16.7

View result in a separate tab

Test name	Executions per second
1 / Math.sqrt()	8442.7 Ops/sec
Fast inverse sqrt	9191.3 Ops/sec

Math.sqrt() vs Fast inverse sqrt (version: 0)

Comparing performance of: 1 / Math.sqrt() vs Fast inverse sqrt

Created: 3 years ago by: Guest

Jump to the latest result

1 / Math.sqrt()

Fast inverse sqrt

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A