4.3.2 Making a New Network

Now, lets make the Network. Select .networks / New / Network and Ok. You now have a blank Network object, and a NetView window in which to view it.

Click New Layer(s), set the Number to 3 (by editing the number field or using the increment/decrement buttons), and hit Ok. Your three layers will appear, but at this point none of them contain any units. The NetView is now in ReShape mode (the corresponding mode button is highlighted). So, if you select "Layer_0", you can start to reshape it. Click and hold in the line you see above the layer label (this line is a layer-frame with no space in it yet) and drag the mouse to the right; boxes will appear corresponding to unit-spaces. When you have 4, stop and let go. You've created a frame for four units. Click on the line above "Layer_1" to create a frame for the two hidden units; drag right until two boxes appear. Finally click on the line above the "Layer_2" label, and create a frame for the four output units. You now have frames but no units; to create the units, in all three layers at once, just click on Build All. The units should all now be visible, and the default act variable selected, indicating that your are viewing their activation states, which should all be zero.

You can move the hidden layer to be centered, by selecting Move mode then dragging the hidden layer with the mouse. Note that things move in "chunks" of the size of a single unit, so you will have to move the mouse a certain amount before the layer itself moves. It's a good idea to go back to Select mode after moving by hitting Select.

Also, clicking the Init button will adjust the display of the network to fill the available space, and generally fix any display problems. It is automatically performed most of the time, but you can use the Init button if the display doesn't look right for some reason.

Now we need to make connections. Actually, you first make Projections then create connections within the projections. A projection is to a connection what a layer is to a unit; it represents a bunch of connections that connect units in two layers. In any case, you need to create two projections. One to the hidden layer from the input layer, and one to the output layer from the hidden layer. In each case:

  • Select the receiving layer with the left mouse button. You want to see the frame around all of the units highlighted. This should occur on the first click; if that's not what you see, keep clicking until it is; (you're cycling the selection through the layer, all the units, and the unit under the mouse).
  • Add the sending layer to the selection using the "extend-select", which can be done with either the middle mouse button, or the Shift key plus the left mouse button, depending on whether you come from a Unix or a Mac background. Now both the sending and receiving layers should be highlighted. If you make a mistake, click the left mouse button in the background area of the NetView between the layers to unselect the layers and start over with the previous step.
  • When you have 2 layers selected, click New Prjn(s), which will be highlighted. A Projection arrow should appear between the two layers. Note that the arrow head of the projection arrow is unfilled (outline) indicating the the actual connections have not been created yet.

    After you do this for both projections you will have two unfilled arrows. Now click Connect All and your projections will be filled with connections to each unit on the receiving end from each unit on the sending end. Now the arrow heads of the projections will be solid indicating that their connections have indeed been created. You may verify this by clicking on the r.wt button and using the finger pointer to view the weights of some of the hidden and output units. When you are finished looking around, return to viewing the activations by pressing act.

    And your network is complete.