<?php
// Per wikipedia ADX is "an indicator of trend strength in a series of prices of a financial instrument."
// The original implementation used 14 days.
$highs = array(118.99, 119.14, 120.5, 115.23, 115.93, 118.829, 116, 112.2, 110.88, 110.19, 112.86, 112.11, 110.25, 112.44);
$lows = array(112.68, 115.26, 112.5, 110, 112.8, 113.61, 112.04, 108.71, 106.09, 103.1, 109.16, 106.77, 105, 107.67);
$closes = array(112.82, 117.32, 113.49, 112, 115.355, 115.54, 112.13, 110.34, 106.84, 110.08, 111.81, 107.12, 108.22, 112.28);
$time_period = floor(count($highs) / 2); // Per Wikipedia on the ADX indicator calculation:
// UpMove = today's high − yesterday's high
// DownMove = yesterday's low − today's low
//
// Thence: The maximal length for $time_period
// is: floor(count($the_number_of_samples) / 2);
var_dump(trader_adx($highs, $lows, $closes, $time_period));
/*
array(1) {
[13]=>
float(48.909)
}
*/