### Using Variables

Instead of reading data into the X, Y, Z or Regular Grid buffers, it is possible to use directly SIC variables in some GREG commands. Currently, the following commands support SIC variables as extra arguments :

          GREG1\CONNECT [Xv Yv]
          GREG1\CURVE [Xv Yv] [/VARIABLE Z [Zv]]
          GREG1\HISTOGRAM [Xv Yv]
          GREG1\ERRORBAR Type [Xv Yv Zv [Orv]]
          GREG1\POINTS [Xv Yv] [/SIZE maxsize [Zv]]
          GREG1\VALUES [Xv Yv Zv]

where, if not specified, the Xv Yv Zv variables default to the X Y Z buffers, which are known as SIC variables of the same names.

SIC variables are defined using command SICDEFINE, and can be external tables or images. See SIC documentation, or use HELP DEFINE within GREG for more details.

The option /VARIABLE of command RGDATA indicates that the argument is the name of a known SIC variable, instead of a file name. This can be used to contour directly 2-D SIC variables. Moreover, the Regular Grid is known as a SIC variable named RG, hence it is possible to assign values to RG within GREG . This does not modify the pixel to user coordinates conversion formula.