Dealing with Large and Other Non-standard Numbers

## 10.8 Dealing with Large and Other Non-standard Numbers

In many external solvers, infinities or very large numbers are not handled directly. Instead, these solvers define a large (floating point) number to be infinity. However, the problem that is sent to the external solver may contain values greater than the solver’s notion of infinity. This is handled in the following way:

- If a variable’s range extends beyond the solver’s infinity, the range is rounded down.
- If some coefficient (constant) in the problem is outside the solver’s range, an out of range error would be raised when this is detected (and the problem is not passed to the external solver).

In addition, ECLiPSe supports numeric types that are not generally available, e.g. bounded real and rational. These are converted into floating point numbers before they are passed to the external solver.