VLINES is the jGraph module of jLab.

 VLINES   Add vertical lines to a plot.
 
    VLINES(X,STYLE) puts vertical lines at locations X having style
    described by the string STYLE.  VLINES draws the lines to fit the
    current axis.
 
    The SYTLE strings follow the format specified in LINESTYLE.  Thus
    STYLE='2b--' draws blue dotted lines of width 2.
 
    VLINES(X) uses the default STYLE='g--', a green dashed line.
 
    H=VLINES(...) returns an array of handles H to the lines.
 
    See also HLINES, DLINES.
    __________________________________________________________________
    This is part of JLAB --- type 'help jlab' for more information
    (C) 2000--2016 J.M. Lilly --- type 'help jlab_license' for details