Returned result does not match length of MA for trader_dema and trader_tema

[robertgdev]

I should preface this by saying that I'm not 100% sure that my understanding of these functions is correct and that I don't know that if this is a real issue, whether it's an issue of this extension or of the underlying ta-lib.

Consider the following test code for dema

<?php


$data   = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100];
$result = trader_dema($data, 3);
var_dump("LEN = 3", $result);
$result = trader_dema($data, 4);
var_dump("LEN = 4", $result);
$result = trader_dema($data, 5);
var_dump("LEN = 5", $result);

This results in the following output:

string(7) "LEN = 3"
array(6) {
  [4]=>
  float(50)
  [5]=>
  float(60)
  [6]=>
  float(70)
  [7]=>
  float(80)
  [8]=>
  float(90)
  [9]=>
  float(100)
}
string(7) "LEN = 4"
array(4) {
  [6]=>
  float(70)
  [7]=>
  float(80)
  [8]=>
  float(90)
  [9]=>
  float(100)
}
string(7) "LEN = 5"
array(2) {
  [8]=>
  float(90)
  [9]=>
  float(100)
}

There is a similar issue with the tema MA, but I'm not going to bore you with this until we establish that this is indeed a problem. Since this is a moving average indicator, I would expect the result to have N-L (where N is the number of input items and L is the length/period of the MA) items. However this is clearly not the case. Can you please comment on this?