PowerShell Perfomance-Test: Get the Maximum

Introduction:

Efficiency is key when working with PowerShell, and maximizing performance is a common goal for script developers. In this post, we'll explore various techniques for retrieving the maximum number from arrays of different sizes, comparing well-known approaches like Measure-Object, Sort-Object and a more mathematical method.

Methods:

1. Measure-Object:

To retrieve the maximum number using Measure-Object, the following command is used:

(@(1,3,55,69,13,37)| Measure-Object -Maximum).Maximum 

2. Sort-Object:

Another approach involves sorting the array and extracting the highest number from the last index:

(@(1,3,55,69,13,37)| Sort-Object)[-1]

3. Mathematical Approach:

Utilizing the [System.Math] class and its Max method requires a loop through the array:

$Numbers = (@(1,3,55,69,13,37)
$maxValue = $Numbers[0] #we need to start with an number
foreach($num in $Numbers){
    $maxValue = [System.Math]::Max($Num,$maxValue)
}

Performance Testing:

For a comprehensive performance comparison, three arrays of different sizes were created:

$NumbersLarge   = get-random -min 0 -max 1gb -count 20mb
$NumbersMedium  = get-random -min 0 -max 1gb -count 1mb
$NumbersSmall   = get-random -min 0 -max 1gb -count 100kb

Results:

Small List:

Technique Time            RelativeSpeed Throughput
--------- ----            ------------- ----------
Math      00:00:00.144915 1x            34.5/s
Measure   00:00:00.602446 4.16x         8.3/s
Sort      00:00:02.053357 14.17x        2.44/s

Medium List:

Technique Time            RelativeSpeed Throughput
--------- ----            ------------- ----------
Math      00:00:01.377477 1x            3.63/s
Measure   00:00:11.163644 8.1x          0.45/s
Sort      00:00:31.034414 22.53x        0.16/s

Large List:

Technique Time            RelativeSpeed Throughput
--------- ----            ------------- ----------
Math      00:00:26.392599 1x            0.19/s
Measure   00:01:57.695910 4.46x         0.04/s
Sort      00:18:38.731559 42.39x        0/s

Conclusion:

The [System.Math]::Max() method consistently outperforms Measure-Object and Sort-Object, particularly for larger datasets. Although its implementation may be less intuitive, encapsulating it in a function enhances usability.

Function Implementation:

function Get-MaxNumber {
    param (
        [int[]]Numbers
    )
    $MaxValue = $Numbers[0]
    foreach($num in $Numbers){
        $MaxValue = [System.Math]::Max($MaxValue,$num)
    }
    return $MaxValue
}

In scenarios where milliseconds matter and the primary goal is to retrieve the maximum number, the targeted solution using [System.Math]::Max() proves to be a powerful choice.

If you have any thoughts or feedback on this topic, feel free to share them with me on Twitter at Christian Ritter.

Best regards, Christian