Selects one of two paths based on one or more conditions calculated in an equation. This block is the familiar flow-charting symbol.
The item exits at the Y output connector if the equation determines that Path = YesPath; the item exits at the N output connector if the equation determines that Path = NoPath. Model conditions determine which output connector the item takes: the value inputs at the bottom of the block give information regarding model conditions.
Enter the equation in the large box in the dialog. The equation is compiled when the dialog is closed.
You can optionally specify that the decision process takes some time; the default is that it takes no (0) time. If you set the time to greater than 0, you should precede the Decision (2) block with a Repository or Stack block to accumulate and count the items waiting to be processed because the Decision can only contain one item at a time.
Dialog Choices:
Enter an equation in the form...: Enter the logic that determines which path the incoming item will take. The names of the value input connectors are used in the equation just like cell references would be used in a spreadsheet formula.
The decision logic is entered in "IF... ELSE..." or "IF... ELSE IF... ELSE..." form. This translates to:
IF(condition calculates to true) Path = YesPath;
ELSE Path = NoPath;
For example, if you want the item to take the Yes path only when V1 (the leftmost value input connector) equals 2 or is greater than 7, the equation (using standard operators such as == for "equals") would be:
IF (V1 == 2) Path = YesPath;
ELSE IF (V1 > 7) Path = YesPath;
ELSE Path = NoPath;
• Each statement in the equation must end in a semicolon (;).
• If none of the conditions are met, the item exits through the N connector.
• Extend's operators are described in the Help command and in the manual. They are:
+, -, *, /, ^ (exponentiation), % or MOD (modulo), AND, OR, NOT, <> , < (less than), <= (less than or equal to), > (greater than), >= (greater than or equal to), == (equal to).
Name the value inputs...: The names you assign to the five inputs at the bottom of the block, going in order from the leftmost input. The default names are V1 through V5; you can enter names which have more relevance to your model. The names of the value input connectors are used in the equation just like cell references would be used in a spreadsheet formula.
• To access the values from these inputs, assign names to them or use the default names (V1 through V5).
• Names can be alphanumeric but they must begin with a letter or an underscore (_) character. Spaces, dashes, and other punctuation (except for the underscore character) are not allowed. Names are limited to 30 characters; the case of letters in the name is ignored.
• Each connected input must have a name, either the default name or the name you give it.
• The name of each connected input must be used in the equation.
The decision takes...time: The time it takes to make the decision, in time units. The default is zero (0), meaning no time. To specify that the decision process requires some time, choose a value greater than 0.
Connectors:
The item input connector provides the item which will be sent along the Y or N path.
The 5 value input connectors take in values that reflect conditions in the model.
Y: The item takes this path if the equation calculates that Path=YesPath.
N: The item takes this path if the equation calculates that Path=NoPath.
Animation:
A green circle appears at the input connector when an item enters the block and at the output connector at the selected path when the item exits.
