NERO _ _ _ _ _ _ _ _ _ _ _ _ switch

When nero is on, zero assignments (such as matrix elements) are not printed.

examples:

matrix a;
a := mat((1,0),(0,1)); 

  A(1,1) := 1
  A(1,2) := 0
  A(2,1) := 0
  A(2,2) := 1


on nero; 

a; 

  MAT(1,1) := 1
  MAT(2,2) := 1


a(1,2); 

nothing is printed.

b := 0; 

nothing is printed.

off nero; 

b := 0; 

  B := 0

nerois often used when dealing with large sparse matrices, to avoid being overloaded with zero assignments.