为什么bbands是空的

Question

I want to know why is the bbands empty for this data. I get the last 14 rates for the coin and put them in the trader functions to calculate the indicators. 1. Why is the BBANDS empty? 2. Are this the right data I should use for the functions or I need to get the closing data for the last 14 days?

$closes[] = 0.00001345;
$closes[] = 0.00001344;
$closes[] = 0.00001344;
$closes[] = 0.00001346;
$closes[] = 0.00001346;
$closes[] = 0.00001345;
$closes[] = 0.00001344;
$closes[] = 0.00001346;
$closes[] = 0.00001347;
$closes[] = 0.00001348;
$closes[] = 0.00001347;
$closes[] = 0.00001347;
$closes[] = 0.00001346;
$closes[] = 0.00001348;
$closes[] = 0.00001346;
$closes[] = 0.00001348;
$closes[] = 0.00001347;
$closes[] = 0.00001348;
$closes[] = 0.00001349;
$closes[] = 0.00001350;

$rsi = trader_rsi($closes, 14);
var_dump($rsi);

$stochrsi = trader_stochrsi($closes, 14, 3, 3);
var_dump($stochrsi);

$bbands = trader_bbands($closes, count($closes), 2, 2, TRADER_MA_TYPE_SMA);
var_dump($bbands);

---> RSI

array (size=6)
  14 => float 53.333
  15 => float 59.193
  16 => float 55.444
  17 => float 58.289
  18 => float 60.972
  19 => float 63.501

---> STOCHRSI

array (size=2)
  0 => 
    array (size=2)
      18 => float 100
      19 => float 100
  1 => 
    array (size=2)
      18 => float 70.638
      19 => float 91.962

---> BBANDS

array (size=3)
  0 => 
    array (size=1)
      19 => float 0
  1 => 
    array (size=1)
      19 => float 0
  2 => 
    array (size=1)
      19 => float 0