[Duncan_vdH]

In my swak function object I want to set the value of a global variable to the sum of
the values of a variable defined in a cellSet.

The global value has fieldSize 1, but the storedVariables one and two have fieldSize
4000, equal to the number of cells in the set. How do I get a storedVariable of
fieldSize 1 equal to the average value over the cellSet? The syntax is not clear to me.

average(one) is again a variable with fieldSize 4000.

myFunction {
        globalScopes (  
          my_globalvariables      
    );
        type calculateGlobalVariables;
        outputControl timeStep;
        outputInterval 1;
    noReset  true;
        valueType cellSet;
        setName my_set;
        storedVariables (
            {
                name one;     
                initialValue "0";
            }
            {   name two; 
            initialValue "0";
            }
          
    my_global_var=sum(one);
        );