Its suppose to perform the square root of the sum of squares depending on how many inputs are selected
if(selected(${DBH}, '1'), (sqrt(pow(${DBH1}, 2))),
if(selected(${DBH}, '2'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2))),
if(selected(${DBH}, '3'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2))),
if(selected(${DBH}, '4'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2) + pow(${DBH4}, 2))),
if(selected(${DBH}, '5'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2) + pow(${DBH4}, 2) + pow(${DBH5}, 2))),
if(selected(${DBH}, '6'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2) + pow(${DBH4}, 2) + pow(${DBH5}, 2) + pow(${DBH6}, 2))),
if(selected(${DBH}, '7'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2) + pow(${DBH4}, 2) + pow(${DBH5}, 2) + pow(${DBH6}, 2) + pow(${DBH7}, 2))),
if(selected(${DBH}, '8'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2) + pow(${DBH4}, 2) + pow(${DBH5}, 2) + pow(${DBH6}, 2) + pow(${DBH7}, 2) + pow(${DBH8}, 2))),
if (selected(${DBH}, '9'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2) + pow(${DBH4}, 2) + pow(${DBH5}, 2) + pow(${DBH6}, 2) + pow(${DBH7}, 2) + pow(${DBH8}, 2) + pow(${DBH9}, 2))),
if(selected(${DBH}, '10'), (sqrt(pow(${DBH1}, 2) + pow(${DBH2}, 2) + pow(${DBH3}, 2) + pow(${DBH4}, 2) + pow(${DBH5}, 2) + pow(${DBH6}, 2) + pow(${DBH7}, 2) + pow(${DBH8}, 2) + pow(${DBH9}, 2) + pow(${DBH10}, 2))))))))))))