With an exhaustive search, the number of portfolios that the TURF procedure must evaluate can become extremely large. Currently, we have placed a limitation of 5,000,000 portfolios to evaluate exhaustively in any one TURF run. If you specify a run that exceeds this limit, the software will automatically switch to a stepwise algorithm. The formula to determine how many portfolios the exhaustive TURF procedure must process is as follows.
m is the total number of items in your study
n is the size of the portfolio to optimize
For example, searching for an optimal portfolio of 5 items from 50 leads to 2,118,760 possible portfolios to evaluate, which the tool will do exhaustively. But, searching for 6 items out of 50 leads to 15,890,700 possible portfolios, which exceeds the limit and will therefore be solved using the stepwise algorithm.