Draw arrows

Analytica User GuideCreate and edit a modelDraw arrows

You must be in edit mode to draw or remove arrows (influences) between variable nodes. Drawing is initiated by dragging from the hover icon. Drawing an arrow from variable or function A to B puts A in the list of inputs of B. This makes it conveniently available to select from the inputs menu when creating or editing the definition of B (see Definitions).

Draw an arrow

To draw an arrow, hover over the origin node until the hover icons appear, then drag from the hover icon to the destination node (which will highlight) and release the mouse.

To speed up drawing arrows from multiple nodes to a single destination, select all the origin nodes. Then drag from any origin node's hover icon to the destination node. When you release the mouse, it draws arrows from all the origin nodes.

Tip

Some arrows are hidden. They do not appear even when you try to draw them. For example, by default, arrows to and from indexes and functions are not shown. You can change these settings in the Diagram Style dialog and Node Style dialog.

Remove an arrow

• Click the arrow to select it, then press the Backspace or Delete key, or
• Just redraw the arrow from the origin node to the destination node. If the origin variable is used in the definition of the destination, it asks if you really want to remove it.

Tip

When you enter or edit a definition (Creating or editing a definition), Analytica automatically updates the arrows into the variable to reflect those other variables that it mentions (or does not mention).

Influence cycle or loop

An influence cycle or loop occurs when a variable A depends on itself directly, where A → A, or indirectly so that the arrows form a directed circular path, e.g., A → B → C → A.

If you try to draw arrows that would make a cycle, it warns and prevents you. The exception is if at least one of the variables in the cycle is defined with the Dynamic function, and contains a time- lagged dependence on another variable in the cycle, shown as a gray arrow (see Dynamic Simulation), or a variable defined by Iterate which may depend on itself.

The meaning of influence arrows

When there are arrows between variables in different modules, they are reflected by arrows to and from the module nodes.

Arrow from a variable to a module

Arrow from a module to a variable

Arrow from variable node to variable node

Arrow from variable node to module node

Arrow from module node to variable node

Arrow from module to module

Double-headed arrow between module nodes

Small arrow-head on left (right) shows menu with remote inputs (outputs) (

Press on the arrowhead to the left (right) of node to see a menu listing all local and remote inputs (outputs). You can select an object from these menus to jump to see that object node in its parent diagram. For more go to Seeing remote inputs and outputs

See Also

• Draw arrows between modules
• Tutorial: Drawing arrows between variables
• Tutorial: Drawing arrows between nodes
• GetArrowsOnDiagram
• Model building by mouse
• Definitions

Create and edit nodesDraw arrowsDraw arrows between modules