ROUNDBF _ _ _ _ _ _ _ _ _ _ _ _ switch
When rounded is on, the normal defaults cause underflows to be converted to zero. If you really want the small number that results in such cases, roundbf can be turned on.
on rounded; exp(-100000.1^2); 0 on roundbf; exp(-100000.1^2); 1.18441281937E-4342953505
If a polynomial is input in rounded mode at the default precision into any roots function, and it is not possible to represent any of the coefficients of the polynomial precisely in the system floating point representation, the switch roundbf will be automatically turned on. All rounded computation will use the internal bigfloat representation until the user subsequently turns roundbf off. (A message is output to indicate that this condition is in effect.)