Widgets and wires

Minsky’s major components, including Godley Tables (in two formats, widget and tabular view) parameters, variables, stocks and integrals are shown in Figure 12. Parameters, constants and mathematical operators are shown are shown in blue, while all other user-defined components (variables, stocks, integrals) are shown in red.

Figure 12: Minsky's basic components

To make a model using Minsky’s components, you have to wire them together.

Components have input and output ports, which are shown as circles when your mouse hovers over a component. The number of such ports depends on the component. Text boxes have none; parameters have an output port, but no input port; stocks are defined in and given numerical values by a Godley Table, and therefore also have only an output port when placed on the canvas; variables have an input and an output port; operators like the plus widget have two input ports and one output port. In Figure 12, the mouse was hovering over the Integral block, and therefore its output port and two input ports—one for the flow into the integral block, the other for its initial conditions—are visible.

A Minsky model is constructed by wiring together components, using the output and input ports. To wire elements together, you click in an output port, which causes a wire with an arrowhead to appear. Hold the mouse button down and drag the arrowhead towards the input port you wish to attach it to. When you are close, release the mouse button and the arrowhead will snap to the nearest input port.

In Figure 13, Interest has been defined as the InterestRate times Debt.

Figure 13: Multiplying a parameter and a variable together to produce another variable.

Click on the Equations Tab and you will Equation (1):

Minsky continues to document your model in mathematical notation as you build it. The equations can be exported for use in a word processing program using the LaTeX option on the Export Canvas as item on the File menu.

Wires are straight by default, but can easily be curved. When your mouse is hovering over a wire, a blue dot will appear on the wire. Click on the blue dot (or anywhere else on the wire) and drag and you will change the shape of the wire into a curve.

This can get quite elaborate, and we allow for this getting out of control by the right-click menu item “Straighten” when you are hovering over a wire.

Figure 14: Curving a connection wire

You will note that the Barney points in the opposite direction to Fred and Wilma in Figure 15; this is executed by the “Flip” command on the right menu for entities like variables, parameters, mathematical operators etc. Arbitrary angles are supported via the right-click Edit menu—see Figure 16.