View source for How to visualize a relation between objects and variables

'''Relation VM'''

When a pointer or a reference is used in a computer program, typically a programmer wants to establish a binary relation between two objects. Visualizing a binary relation is common and, in most cases, not dispensable. The visualization of a binary relation can be achieved in several ways in xDIVA.

First, any UBVM that has two ends like 3Dline_ubvm is best suitable for visualizing a binary relation.

'''Example <nowiki>city.ja</nowiki>va'''

Let's use <nowiki>city.ja</nowiki>va as an example to show how an&nbsp;'''3Dline_ubvm'''&nbsp;can be used to represent a relation

* Open the example as follows:

[[File:Linerelation-0.jpg]]

* Visualize&nbsp;'''"<nowiki>map[</nowiki>0]"'''&nbsp;and choose ball_laser (in Composite tab) to visualize the reference.
* Click the grey ball to unfold the reference
* When mapping dialog pop up, please construct the following mapping

[[File:Linerelation-1.jpg]]

# In this mapping, we use a cube to represent variable&nbsp;'''_x'''&nbsp;and a sphere to represent&nbsp;'''_y'''.
# Open the set node attribute of cube and sphere by right click on them.
# Remember to click outport button (see Fig. below)
# Make&nbsp;'''_vm_rx''',&nbsp;'''_vm_ry''',&nbsp;'''vm_rz'''&nbsp;visible
# Add line_ubvm
# Complete the links as the above figure.

[[File:Linerelation-2.jpg]]

Finally, you will see a line is established between cube and sphere. You can drag the cube and sphere because the container we use is a freestyle container. You can replace&nbsp;'''line_ubvm'''&nbsp;with&nbsp;'''laser_ubvm'''&nbsp;if you like.

[[File:Linerelation-3.jpg]]