# Stocks

Purpose: Stocks are accumulations. They collect whatever flows into them, net of whatever flows out of them.

Selection and Placement:

- Select the stock icon by clicking once on the icon in the Building Block palette.

- Move the mouse to the desired location on the diagram.

- Click once to deposit the stock.

Notes: The default stock type is the Reservoir. Think of a Reservoir as a pool of water, or as an undifferentiated pile of "stuff." A Reservoir passively accumulates its inflows, minus its outflows. Any units which flow into a Reservoir will lose their individual identity. Reservoirs mix together all units into an undifferentiated mass as they accumulate.

The default, Reservoir, stock type is signified by a simple rectangle. To select a conveyor, sub-model, queue, or oven, click and hold the stock icon on the palette. Then, select the appropriate stock type from the drop-down list that appears.

Surface Operations: Figure 4-11 details surface operations which may be performed on a stock.

Figure 4-11 Stock Surface Operations

Mapping Dialog Operations: When you open a Stock in the Mapping mode, you'll enter its Mapping dialog. Figure 4-12 details the operations within this dialog.

Figure 4-12 Reservoir Dialog - Mapping Mode

Modeling Dialog Operations: In the modeling mode, the Reservoir dialog sports additional controls. These are identified and described in Figure 4-13.

Figure 4-13 Reservoir Dialog - Modeling Mode

Reservoir Dialog Notes:

- The expression in the equation box provides an initial value for the stock, and is evaluated only at the outset of a simulation run.

- It is possible to generate an initial value for Reservoirs via a link from another application. On the Macintosh using System 7, you can use Publish & Subscribe. On Windows, you can use Dynamic Data Exchange (DDE). See Importing and Exporting Data for details on Publish & Subscribe and DDE.