Optstrategy

yjy

I'm trying to use cerebro.optstrategy for some optimization, but it doesn't seem to be working.

I have started with cerebro.optstrategy(myStrat, a=5, b=10) to try a single combination. Then I say cerebro.run().

It works with cerebro.addstrategy but when I run the optstrategy, the run doesn't stop and I don't know why... Hope you can help.

backtrader

That information is simply too little to work with. A minimum working snippet is always helpful.

yjy

Sorry, I didn't have access to a computer at the time I was writing. Here is what I was trying to do. Assuming I was running the sample code given by backtrader front page:

from datetime import datetime
import backtrader as bt
    
class SmaCross(bt.SignalStrategy):
        params = (('pfast', 10), ('pslow', 30),)
        def __init__(self):
            sma1, sma2 = bt.ind.SMA(period=self.p.pfast), bt.ind.SMA(period=self.p.pslow)
            self.signal_add(bt.SIGNAL_LONG, bt.ind.CrossOver(sma1, sma2))
    
cerebro = bt.Cerebro()

data = bt.feeds.YahooFinanceData(dataname='YHOO', fromdate=datetime(2011, 1, 1), todate=datetime(2012, 12, 31))

cerebro.adddata(data)

cerebro.addstrategy(SmaCross)
cerebro.run()

Now, assuming that I want to adjust various pfast and pslow value using the optstrategy function.

When I replace

cerebro.addstrategy(SmaCross)
cerebro.run()

with

cerebro.optstrategy(SmaCross, pfast=(10,20,30), pslow=(60, 80, 100))
cerebro.run()

the code just keeps running for a long time without printing out anything. I'm just wondering if I'm missing something. Thanks.

backtrader

@yjy said in Optstrategy:

the code just keeps running for a long time without printing out anything

That's what happens during an optimization, things take longer. In any case the code contains no output statements (print) for example. The real question would what's the meaning of long time.

Since you use YahooFinanceData you have to take into account that the servers for the original data are down and only the newest version (a few days old) can re-download from the alternative service (which may or may not be there in the future)

yjy

Thank you for the quick response. Buy long time, I actually meant it never really stopped running. And in my real code, I do have lots of print functions which I was able to see using the original code

cerebro.addstrategy(SmaCross)
cerebro.run()

Of course, I may just have a really slow computer.

backtrader

One of the things about a snippet which reports a problem .. it has to actually produce the problem. And obviously the one above isn't the real one.

In any case

Printing to stdout during parallel processing makes no sense, because the output will get intermingled, rather sooner than later.
If you are running under Windows, the output to stdout is buffered and it takes a large amount of output to produce a printout.