Share New Research 
I am currently trying to code a momentum stock trading algorithm. I also managed to get it working for a universe of 30 stocks. But as I increase the number of stocks to trade I get the following Error:
ValueError : all the input array dimensions for the concatenation axis must match exactly, but along dimension 1, the array at index 0 has size 90 and the array at index 1 has size 2
There is also no information about where (in which line) the error occurred. I attached the code. in the code I commented out a list called self.dji. If I use this list for my universe everything is working. Just when I increase the number of tradable stocks and use the list you can see in the code it stops working. My only explanation so far would be some sort of bug.
Looking forward for replies.
Kind regards
Luca Würker
Varad Kabade
Hi Luca Würker,
Would you mind attaching a code snippet/backtest highlighting the issue?
Best,
Varad Kabade
Luca Würker
The material on this website is provided for informational purposes only and does not constitute an offer to sell, a solicitation to buy, or a recommendation or endorsement for any security or strategy, nor does it constitute an offer to provide investment advisory services by QuantConnect. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. QuantConnect makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances. All investments involve risk, including loss of principal. You should consult with an investment professional before making any investment decisions.
To unlock posting to the community forums please complete at least 30% of Boot Camp.
You can continue your Boot Camp training progress from the terminal. We hope to see you in the community soon!