Sum function
The Sum function determines the sum of values in the numeric node, sets of numeric nodes, or numbers in parameters.
Parameter: input, input ...
The numeric nodes to add. These can come from recurring or nonrecurring source nodes, the results of other functions, or values that you specify.
You cannot specify a default value (or constant) for the input parameters of this function but you can specify a variable with a default value and then pass that variable as an input parameter to this function. For more information see Specifying Default Values for Functions that Allow Recurring Nodes as Input.
Returns: number
The total sum of all parameters. If any parameter is a nodeset, the total includes values for every node in the set. If any parameter is not a number or a numeric node set, returns NaN (not a number).