intersection🔗
Short description🔗
intersection — Calculate the intersection of two regions.
Signature🔗
intersection( region Region1, region Region2, out region RegionIntersection )
Description🔗
intersection calculates the intersection of the regions
in Region1 with the regions in Region2. Each
region in Region1 is intersected with all regions in
Region2. That is, internally all regions of Region2
are united to a single region before the individual regions of
Region1 are intersected with the united region. The order of
regions in RegionIntersection is identical to the order
of regions in Region1.
Attention🔗
Empty input regions are permitted. Because empty result regions are possible, the system flag 'store_empty_region' should be set appropriately.
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
Regions to be intersected with all regions in Region2.
Region2 (input_object) region(-array) → object
Regions with which Region1 is intersected.
RegionIntersection (output_object) region(-array) → object
Result of the intersection.
Number of elements: RegionIntersection <= Region1
Complexity🔗
Let \(N\) be the number of regions in Region1, \(F_{1}\) be
their average area, and \(F_{2}\) be the total area of all regions in
Region2. Then the runtime complexity is
\(O(F_{1} \log{(F_{1})} + N * (\sqrt{F_{1}} + \sqrt{F_{2}}))\).
Result🔗
intersection 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
See also
Module🔗
Foundation