gda — Return handle of default axes.
a = gda()
a = get("default_axes")The default axes is a graphic entity which is never drawn. It is used as a reference for the axes properties default values. These default properties values are used to initialize new axes inside figures.
The gda function returns the handle on the default axes.
    The user can use this handle to set or get the axes properties default
    values.
Note that an equivalent default graphic entity exists for figure
    entities too (see gdf).
 
a=gda() // get the handle of the model axes 
// set its' properties
a.box="off";
a.foreground=2;
a.labels_font_size=3;
a.labels_font_color=5;
a.sub_tics=[5 5 3];
a.x_location="top";
//now used the model axes for drawing
subplot(211) //create an axes entity
plot2d() 
// set other model's properties
a.background=color('gray')
a.grid=[5 5 5];
subplot(212)
t=0:0.1:5*%pi; 
plot2d(sin(t),cos(t)) 
 
set(a,"default_values",1); // return to the  default values of the model
                           // see sda() function
clf()
plot2d(sin(t),cos(t))