6.2 Interpretation of the Undefined Value (RUNDEF)

In the subroutines of UUPACK/UVPACK/UHPACK, the undefined values (RUNDEF) can be specified as the independent or dependent variables. The following interpretations are made when the undefined value is specified.

When the independent variable is rundef:
The data is interpreted to have constant intervals for the independent variables. The defined range of the independent variables is specified by USIDV(UMIN, UMAX). When this range is not specified, the whole window is considered as the defined range of the independent variables. TYPE1 and TYPE2 routines divide the defined region into n-1 equal sections, and TYPE 3 and TYPE4 into n  equal sections.
When the dependent variable is rundef:
The value of the internal variable UREF (initial value = 0) is considered as specified. However, the undefined value can be specified for the dependent variable only for TYPE2 and TYPE4 routines with 2 dependent variables.
The undefined value of the dependent variable assumes a case where the bar is always drawn from the coordinate axis to a specified position, for a subroutine in which the top and bottom position of the bar is specified, such as in a bar graph.