Merges two index domains.

If both a and b are null, returns a null index domain.

If exactly one of a and b is non-null, returns the non-null domain.

Otherwise, a and b must be compatible:

• a.rank() == b.rank()

• For all dimension i for which !a.labels()[i].empty() && !b.labels()[i].empty(), a.labels[i] == b.labels[i].

• For each lower/upper bound of each dimension i, either a and b have the same bound (including implicit bit), or at least one of the bounds is implicit and infinite.

In the merged domain, non-empty labels take precedence, and explicit/finite bounds take precedence over implicit/infinite bounds.

Parameters:¶

IndexDomainView<> a¶

Domain to merge. May be null.

IndexDomainView<> b¶

Other domain to merge. May be null.

Returns:¶

The merged domain, or a null domain if a and b are both null.

Error absl::StatusCode::kInvalidArgument:¶

if a and b are not compatible.