// 如果你没有 php_trader 库或需要超过 3 位小数精度，
// 你可以使用这个函数
public static function linearreg_slope( $valuesIn, $period )
{
{
$valuesOut = array();
$startIdx = 0;
$endIdx = count($valuesIn) - 1;
$sumX = $period * ( $period - 1 ) * 0.5;
$sumXSqr = $period * ( $period - 1 ) * ( 2 * $period - 1 ) / 6;
$divisor = $sumX * $sumX - $period * $sumXSqr;
{
for ( $today = $startIdx, $outIdx = 0; $today <= $endIdx; $today++, $outIdx++ ) {
$sumXY = 0;
$sumY = 0;
if ( $today >= $period - 1 ) {
{
for( $aux = $period; $aux-- != 0; ) {
$sumY += $tempValue = $valuesIn[$today - $aux];
}
$sumXY += (double)$aux * $tempValue;
}
}
}
}
