Benchmark: Test for - MeasureThat.net

Script Preparation code:

var arr = [];
  for (var i = 0; i < 1000; i++) {
    arr[i] = i;
  }

  function someFn(ix) {
    return ix * 5;
  }

Tests:

for 3
var l = arr.length; var result=0; for (var i = 0; i < l; i++) { result += arr[i] * 5; }
for 4
var result=0; for (var i = 0; i < arr.length; i++) { result += arr[i] * 5; }
copy
var arr = []; for (var i = 0; i < 1000; i++) { arr[i] = i; } var result=0; for (var i = 0; i < arr.length; i++) { result += arr[i] * 5; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for 3
for 4
copy

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared, and discussed.

**Benchmark Definition**

The benchmark definition json represents a simple JavaScript function that generates an array of numbers from 0 to 999, multiplies each number by 5, and then sums up the results. The script preparation code includes this setup, along with two custom functions: `someFn(ix)` which simply returns the input multiplied by 5.

**Script Preparation Code**

The script preparation code initializes an array `arr` with 1000 elements and populates it with numbers from 0 to 999 using a for loop. It also defines the `someFn(ix)` function, which is not actually used in the benchmark but is included for comparison purposes.

**Html Preparation Code**

There is no Html preparation code provided, which means that this benchmark does not include any HTML-related components or dependencies.

**Individual Test Cases**

The test cases are variations of the same benchmark definition, with different numbers of iterations:

1. **"for 3"`**: This test case uses a for loop to iterate over the array elements only three times.
2. **"for 4"`**: Similar to "for 3", but with four iterations.
3. **"copy"`**: This test case creates a new empty array and then iterates over its length, multiplying each number by 5.

**Comparison of Options**

The benchmark is comparing the performance of three approaches:

1. **Direct iteration**: Using a for loop to iterate directly over the `arr` array.
2. **Array length iteration**: Iterating over the length of the `arr` array using a for loop, which may be faster due to caching or other optimizations.
3. **Creating a copy and iterating**: Creating a new empty array and then iterating over its length.

**Pros and Cons**

1. **Direct iteration**:
	* Pros: Simple, straightforward approach.
	* Cons: May incur overhead from the for loop itself.
2. **Array length iteration**:
	* Pros: May be faster due to caching or other optimizations.
	* Cons: May not work correctly if the array is modified during iteration.
3. **Creating a copy and iterating**:
	* Pros: Avoids direct iteration, potentially reduces overhead.
	* Cons: Creates additional memory allocations and copies.

**Library Usage**

There are no libraries explicitly used in this benchmark. However, it's worth noting that `arr.length` is a property of the array object, which is a built-in JavaScript concept.

**Special JS Features/Syntax**

None are mentioned or utilized in this benchmark.

**Other Alternatives**

Some alternative approaches could be explored for improving performance:

1. **Using `forEach()` instead of `for` loops**: JavaScript has a built-in `forEach()` method that can simplify iteration and potentially improve performance.
2. **Using `Array.prototype.map()`**: Instead of creating an empty array and iterating over its length, you could use the `map()` method to create a new array with the desired values.

These alternatives would require modifications to the benchmark definition and test cases to take advantage of these features.

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (X11; Fedora; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36

Browser/OS: Chrome 57 on Fedora

View result in a separate tab

Test name	Executions per second
for 3	7597.5 Ops/sec
for 4	3797.0 Ops/sec
copy	102593.8 Ops/sec

Related benchmarks:

Test for (version: 0)

Comparing performance of: for 3 vs for 4 vs copy

Created: 7 years ago by: Guest

Jump to the latest result

for 3

for 4

copy

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):