What are different between bta-lib, ta-lib and internal BackTrader indicators?

Quỳnh H Nguyễn

Hello,

Could anyone talk about different between them? I take a look around the sample of talib integration sample, and see that the internal indicators of BackTrader and ta-lib almost the same.

Now BackTrader introduce the new one: bta-lib. And if the different are clarify for purposes and use cases are better. If this rookie's question is annoyed, please delete it!

Thank you!

run-out

ta-lib is the python wrapper for the well established Technical Analysis Library external to backtrader.

Backtrader makes use of this library with it's own connection to the ta-lib. These indicators are also call TA-Lib in backtrader, hence more confusion. You will need ta-lib python wrapper installed to use this.

The last library is the very newly minted bta-lib. This was created by the maker of backtrader as a handy library for doing technical analysis when using pandas dataframes. In a nutshell, you can put in a OHLCV dataframe and BTA-LIB will spit out the indicator. It works quite well and is easier to use that the original ta-lib library.

tx_562

@run-out said in What are different between bta-lib, ta-lib and internal BackTrader indicators?:

The last library is the very newly minted bta-lib. This was created by the maker of backtrader as a handy library for doing technical analysis when using pandas dataframes. In a nutshell, you can put in a OHLCV dataframe and BTA-LIB will spit out the indicator. It works quite well and is easier to use that the original ta-lib library.

Does bta-lib interact with the backtrader framework? Or is it meant to be used seprately?

run-out

Seperately I think.

Quỳnh H Nguyễn

I tried with btalib to compare with original TA-Lib

class BTALIBBeginningStrategy(bt.Strategy):
    params = (
        ('MA', 100),
    )

    def __init__(self):
        #self.ma = bt.indicators.MovingAverageSimple(period=self.params.MA)
        self.ma = btalib.sma(self.data.close, period=self.p.MA)

but I got this error

  File "/home/learner/venv/lib/python3.8/site-packages/btalib/indicator.py", line 152, in __call__
    b_init(self, *args, **kwargs)
  File "/home/learner/venv/lib/python3.8/site-packages/btalib/indicators/sma.py", line 28, in __init__
    self.o.sma = self.i0.rolling(window=self.p.period).mean()
  File "/home/learner/venv/lib/python3.8/site-packages/btalib/meta/lines.py", line 394, in real_multifunc_op
    return _MultiFunc_Op(self, *args, **kwargs)
  File "/home/learner/venv/lib/python3.8/site-packages/btalib/meta/lines.py", line 306, in __init__
    trailer = series[self._minidx:]
  File "/home/learner/venv/lib/python3.8/site-packages/backtrader/linebuffer.py", line 163, in __getitem__
    return self.array[self.idx + ago]
TypeError: unsupported operand type(s) for +: 'int' and 'slice'

The code with original TA-Lib runs normally. But I don't understand what the error with btalib. Please explain for new rookies!

Thank you!

run-out

btalib is not meant to be used in backtrader as a replacement for the built in indicators. bta-lib takes in a dataframe and returns a signal.

Quỳnh H Nguyễn

@run-out said in What are different between bta-lib, ta-lib and internal BackTrader indicators?:

btalib is not meant to be used in backtrader as a replacement for the built in indicators. bta-lib takes in a dataframe and returns a signal.

Oh, I believe that the BackTrader's owner want to replace TA-Lib by btalib not only because pure python, but also easier to create customize indicators.

run-out

@Quỳnh-H-Nguyễn I could be wrong of course, I'm only reading the docs. But the main docs make no mention or show no real integration into the backtrader engine. Please let us know if I've got that wrong. It's all very new.

Quỳnh H Nguyễn

@run-out The docs's examples show that btalib runs separately like your mention above. I think maybe in the future backtrader will change something (I think it is just a little change) to use btalib in great backtest framework.

From the docs:

YATALIB
Yet Another Technical Analysis LIBrary. That could well have been the name, and the simple reason to create this library, having "yet another". But neither ... nor.

The reasons:

Having a library which is easy to use and re-use
Offering a correct implementation of indicators
Achieving a readable implementation of indicators
Making it possible to quickly and easily develop new indicators

Sorry if I'm wrong because English is not my native speaking/understanding!

run-out

@Quỳnh-H-Nguyễn This is still an awesome tool. And if you wanted to create a line preloading into cerebro, this would make it dead easy. Cheers

Quỳnh H Nguyễn

@run-out said in What are different between bta-lib, ta-lib and internal BackTrader indicators?:

@Quỳnh-H-Nguyễn This is still an awesome tool. And if you wanted to create a line preloading into cerebro, this would make it dead easy. Cheers

yeah, I got some times and don't know the reason. However, it is simple for a rookie like me to begin!