Producing the diagram

 
Syntax

1. BD>cdiag : B, , , , , , , , , , , , ,

2. BD>cdiag : B, 1, , , , , ,

where is the name of a base or element, is an integer, and are real numbers.

 

The CDIAG:  command is used to construct the comparison diagram. Note that the GCLEAR:  command can be used to clear the graphics screen. Furthermore, text can be written to the screen by using the GTEXT:  command. Refer to the cdscaler  and cdradius  controls for changing the relative plotted positions of the observed eigenvectors and the size of the circles drawn to mark them.

All the features summarised on the diagram must be supplied directly: the command carries out no further adjustments of belief constructions. When the base B consists of a single element, a shorter version of the command is required. For both, B is the name of the collection being adjusted. The base B is represented by a node whose coordinates and so forth must have been defined beforehand by issuing an appropriate NODE:  or GRID:  or GRID0:  command.

The number of elements in the base should be given as . The remaining numbers supplied are the eigenvalues and observed eigenvectors as follows.

• For more than one element:

  

  

  

  

• For one element there is only one eigenvalue for each comparison, and one observed eigenvector:

  

  

For each case above, by (0 or 1) we mean the normalised variance with respect to the denominator variance matrix. The required value will be unity except for pathological cases.