union2🔗
Short description🔗
union2 — Return the union of two regions.
Signature🔗
union2( region Region1, region Region2, out region RegionUnion )
Description🔗
union2 computes the union of the region in
Region1 with all regions in Region2.
Internally, all regions of Region2 are united to
a single region before the individual regions of
Region1 are united with the already united region. This
means that union2 is not commutative!
Execution information🔗
Execution information
-
Multithreading type: reentrant (runs in parallel with non-exclusive operators).
-
Multithreading scope: global (may be called from any thread).
-
Processed without parallelization.
Parameters🔗
Region1 (input_object) region(-array) → object
Region for which the union with all regions in Region2 is to be computed.
Region2 (input_object) region(-array) → object
Regions which should be added to Region1.
RegionUnion (output_object) region(-array) → object
Resulting regions.
Number of elements: RegionUnion == Region1
Complexity🔗
Let \(F\) be the sum of all areas of the input regions. Then the runtime complexity is \(O(\log(\sqrt{F}) * \sqrt{F})\).
Result🔗
union2 always returns 2 (H_MSG_TRUE). The behavior in case of
empty input (no regions given) can be set via
set_system('no_object_result',<Result>)
and the behavior in case of an empty input region via
set_system('empty_region_result',<Result>).
If necessary, an exception is raised.
Combinations with other operators🔗
Combinations
Possible predecessors
threshold, connection, regiongrowing, pouring
Possible successors
Alternatives
See also
Module🔗
Foundation