percent - (%) special character
Some predefined variables names begin with % , such as %i (for sqrt(-1) ), %inf (for Infinity ), %pi (for 3.14... ), %T (for the boolean constant "true" ),...
In addition, functions whose names begin with % are special : they are used for primitives and operators overloading (see overloading ).
For example the function %rmr performs the multiplication ( m ) operation x*y for x and y rational matrices ( r ). The coding conventions are given by the readme file in directory SCIDIR/macros/percent .
x1=tlist('x',1,2); x2=tlist('x',2,3); deff('x=%xmx(x1,x2)','x=list(''x'',x1(2)*x2(2),x2(3)*x2(3))'); x1*x2