Benchmark: Is even - MeasureThat.net

Script Preparation code:

function getRandomInt(max) {
  return Math.floor(Math.random() * Math.floor(max));
}

Tests:

normal
let n = getRandomInt(100) console.log(n % 2 == 0)
bitwise
let n = getRandomInt(100) console.log(n & 1 == 0)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
normal
bitwise

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 help explain the JavaScript microbenchmark on MeasureThat.net.

**What is being tested?**

The provided benchmark tests two different ways of checking if a number is even: using the modulo operator (`%`) and using bitwise operations with a mask (`&`).

In both cases, a random integer `n` is generated between 0 and 100, and then checked if it's even by evaluating an expression. The expressions are:

* For the "normal" test case: `let n = getRandomInt(100)console.log(n % 2 == 0)`
* For the "bitwise" test case: `let n = getRandomInt(100)console.log(n & 1 == 0)`

**Options compared**

Two approaches are being compared:

1. **Modulo operator (`%`)**: This is a simple and widely supported way to check if a number is even. It works by finding the remainder of the division of `n` by 2, which will be 0 if `n` is even.
2. **Bitwise operations with a mask (`&`)**: This approach uses bitwise AND operation with a mask value (in this case, `1`) to check if the least significant bit of `n` is set. If it is, then `n` is even.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Modulo operator (`%`)**:
	+ Pros: Simple, widely supported, easy to understand.
	+ Cons: May be slower than bitwise operations for large numbers due to the overhead of division.
* **Bitwise operations with a mask (`&`)**:
	+ Pros: Can be faster than modulo operator for large numbers, as it only requires a single bitwise operation.
	+ Cons: May require more memory or CPU cycles for the mask value, and can be less intuitive for beginners.

**Library usage**

There is no explicit library used in this benchmark. However, some modern browsers may have built-in functions that could potentially optimize these expressions, but they are not used here.

**Special JS feature or syntax**

There are no special JavaScript features or syntaxes being tested here. The focus is on the basic operations and how different approaches compare performance-wise.

**Alternative approaches**

Other alternatives to check if a number is even might include:

* Using the `Math.floor()` function with a divisor of 2, e.g., `let n = getRandomInt(100)console.log(Math.floor(n / 2) == Math.floor(n / 2))`
* Using arithmetic operations like subtraction or addition, e.g., `let n = getRandomInt(100)console.log((n - (n % 2)) == (n - (n % 2)))`

However, these approaches are likely to be less efficient and more complex than the modulo operator and bitwise operations.

Overall, this benchmark provides a simple and informative way to compare the performance of different ways to check if a number is even in JavaScript.

Related benchmarks:

Is even (version: 0)

Comparing performance of: normal vs bitwise

Created: 5 years ago by: Guest

Jump to the latest result

normal

bitwise

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):