Stable Numerics Subroutine Library
Programming Reference Manual
Version 1.0 DD-00006-010
5.2.8 Status functions
bool is_empty() const;
bool is_whole() const;
bool is_signed() const;
bool is_bounded() const;
bool is_singleton() const;
bool is_okay() const;

bool has_zero() const;

These member functions inquire the current status of the interval object.

is_empty()


Whether the interval is empty, that is whether A∈ IR  is a= a= ∅  .

is_whole()


Whether the interval spans the whole R  , that is whether for A ∈ IR  is a= -∞ ∧a-=∞ .

is_signed()


Whether the interval contains a sign, that is for A ∈IR  defined as sgn(a)= sgn(a)  . It is of note that for this definition it is considered that -0 ̸= 0  .

is_singleton()


Whether the interval represents a single value in R  , that is for A∈ IR  defined as a= a⇔ a,a∈ R  .

is_okay()


Determines whether the interval is normalized, if false the interval must be normalized with the respective functions.

has_zero()


Determines whether the interval contains a zero, i.e. whether for a given interval A ∈ IR  it is true that ±0 ∈A , where this function will return true if either or both of -0  and 0  are in A .