Operators

In the “Operators” view you control the algorithmic settings of a node. These settings describe how the node combines input values and local values when the output value of the node is calculated.

The “Algorithm” popup menu is used to choose the fundamental structure of the calculations. The following options are available:

	• Local only
	• Global only
	• Single
	• Double
	• Correlation

If the algorithm is “Local only”, all input from other nodes are ignored. Thus, this option is typically used for nodes with no input.

The “Global only” algorithm, on the other hand, ignores the local values of the node. With this algorithm, there is no point in specifying anything in the “Distribution” view since this is irrelevant to the calculations.

The “Single” algorithm is used if you want to combine both local and global values using a single operator like e.g., a sum.

The “Double” algorithm is used if you want to combine both local and global values using two different operators. In this case all global input is combined using the first operator, referred to as “Operator 1”. Then the result of this operation is combined with the local value using the second operator, i.e., “Operator 2”.

Finally the “Correlation” algorithm is used represent statistical dependence rather than a purely functional dependence.

The presence and appearance of the other items in the “Operators” view depends on the chosen algorithm. In particular, the operator popup menus are available only when they are relevant to the chosen algorithm.

The “Operator 1” popup menu is available when the algorithm is “Global only”, “Single”, or “Double” and contains the following options:

	• Sum
	• Product
	• Maximum
	• Minimum

All these operators act on sets of variables and are symmetric in all arguments.

The “Operator 2” popup menu is available only when the algorithm is “Double” and contains the following options:

	• Sum
	• Product
	• Maximum
	• Minimum
	• Minus
	• Divide
	• Greater than
	• Not less than
	• Less than
	• Not grt. than
	• Equal to
	• Not equal to

All these act on pairs of variables, with the result of the first operator as the first argument, and the local value as the second argument.