I agree that the object is non-linear. At least the rate of return part is linear. I cannot expose too much about the detail of the algorithm. You can change the rrr and play with it to see if it is a local optimal point. :)
This tool's(http://quicark.com/OptimalPortfolio.aspx) principle is: if prices of securities happened in the past, it will happen in the future in a similar way.
From this point of view, we can value the risk as the value fluctuation diverse from the mean route of the portfolio. The...
The tool http://quicark.com/OptimalPortfolio.aspx (how to use it
http://quicark.com/OptimalPortfolioHelp.aspx) can help traders to determine what/how many you need to buy based on your cash, expected return and risk. You need to pick up the stocks by yourself for your portfolio.