XPP enables the user to incorporate a large number of options within an ODE file. These have the form:
@ opt1=value,opt2=value2,
where opt1 is the name of an option and value is the assigned value. Almost every option can also be set within XPP from the menus. Similarly, most items that you want to set in XPP can be set in the ODE file.

The following options can only be set outside the program. They are:

The remaining options can be set from within the program. They are
Plotting options.
Numerical options
Poincare map
Range integration
AUTO options. The following AUTO-specific variables can also be set: NTST, NMAX, NPR, DSMIN, DSMAX, DS, EPSS,EPSL,EPSU, PARMIN,PARMAX, NORMMIN, NORMMAX, AUTOXMIN, AUTOXMAX, AUTOYMIN, AUTOYMAX, AUTOVAR. The last is the variable to plot on the y-axis. The x-axis variable is always the first parameter in the ODE file unless you change it within AUTO.