How accurate/performant is phpFITFileAnalysis::sma() ?

[adriangibbons]

Need to compare performance and output of phpFITFileAnalysis::sma() vs the PHP Trader PECL extension

[adriangibbons]

Tested five FIT files containing power data and captured 23 Critical Power values from 2s to 2hrs and compared results to 3 decimal places.

For three files, results were the same. The other two had just one CP value (20mins in both cases) that were out by only 0.001 watt!

As you can see, using the PHP Trader extension is significantly faster (<0.05s) than using PHP code (25-35s+)! I don't think I can write a function that performs much quicker than the current code:

private function sma($array, $time_period) {
    $sma_data = [];
    $data = array_values($array);
    $count = count($array);

    for($i=0; $i<$count-$time_period; ++$i) {
        $sma_data[] = array_sum(array_slice($array, $i, $time_period)) / $time_period;
    }

    return $sma_data;
}

But if someone else can, then I am very interested to see it!

Results: