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minute order bug

hi

I use the minute backtest. When i trade an order, the context.portfolio.cash didn't change.

Is it a bug?

3 responses

The portfolio and variables are not updated in the middle of a bar. At the beginning of a bar, your algo will read the current state of the parameters and execute all of the commands based on those conditions. The data gets updated at the beginning of the next bar.

For example:

def handle_data(context,data):  
   cash = context.portfolio.cash  
    if cash > 1000:  
        for stock in context.stocks:  
              order(stock, 10)   # when this is ordering, it uses the same value of cash  

To make your strategy more robust, I suggest to use the order_target() functions. They will seek to your target positions and you have less cash management to worry about. The docs are here: https://www.quantopian.com/help#api-order-methods

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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 Quantopian. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. No information contained herein should be regarded as a suggestion to engage in or refrain from any investment-related course of action as none of Quantopian nor any of its affiliates is undertaking to provide investment advice, act as an adviser to any plan or entity subject to the Employee Retirement Income Security Act of 1974, as amended, individual retirement account or individual retirement annuity, or give advice in a fiduciary capacity with respect to the materials presented herein. If you are an individual retirement or other investor, contact your financial advisor or other fiduciary unrelated to Quantopian about whether any given investment idea, strategy, product or service described herein may be appropriate for your circumstances. All investments involve risk, including loss of principal. Quantopian 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.

You can see my code and my testcase.
It seems that the portfolio will update before the day start. But not before the minute start.

If you run your backtest, then go to transactions, you can see that you buy 50,000 shares of apple every minute. The portfolio should be being updated every minute, despite only the daily gains being shown.

Disclaimer

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 Quantopian. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. No information contained herein should be regarded as a suggestion to engage in or refrain from any investment-related course of action as none of Quantopian nor any of its affiliates is undertaking to provide investment advice, act as an adviser to any plan or entity subject to the Employee Retirement Income Security Act of 1974, as amended, individual retirement account or individual retirement annuity, or give advice in a fiduciary capacity with respect to the materials presented herein. If you are an individual retirement or other investor, contact your financial advisor or other fiduciary unrelated to Quantopian about whether any given investment idea, strategy, product or service described herein may be appropriate for your circumstances. All investments involve risk, including loss of principal. Quantopian 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.