Package cds.healpix
Class HealpixNestedFast
java.lang.Object
cds.healpix.HealpixNestedFast
- All Implemented Interfaces:
HashComputer
,HierarchyItem
,NeighbourSelector
,VerticesAndPathComputer
public final class HealpixNestedFast
extends Object
implements HashComputer, VerticesAndPathComputer, NeighbourSelector
A faster, thread-safe, but ugly (sorry: less readable) version of
HealpixNested
.
The code has also been "denormalise" to try to be faster: we introduce redundancy by suppressing
method calls when a method must return more than one elements, ...
Motivations: in Java, all arguments of a function are passed-by-value. And, like most languages,
a function returns only one output. It means that if, e.g. a function as to return a pair of
coordinate you have only two solutions: the first one is to instantiate an object containing
the pair of coordinates and return it, or the method have to take an object and set the pair
of coordinates.
In this "fast version", we duplicate code to avoid creating objects inside critical methods and
we write the results in arguments instead of returning new objects. The instantiation of an
object in Java is cheap, but it cost is not negligible compared to the speed of HEALPix methods.- Author:
- F.-X. Pineau
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final byte[][]
For each of the 12 hash of depth 0, contains the list of the depth 0 neighbours sorted by increasing hash value.static final byte[][][]
Fields inherited from interface cds.healpix.NeighbourSelector
ALL_MAIN_WINDS
Fields inherited from interface cds.healpix.VerticesAndPathComputer
ALL_CARDINAL_POINTS, LAT_INDEX, LON_INDEX
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptiondouble[]
center
(long hash) Compute the position on the unit sphere of the center (in the Euclidean projection plane) of the cell associated to the given hash value.void
center
(long hash, double[] resultLonLat) SeeVerticesAndPathComputer.center(long)
, except that the result is stored in the given array.int
depth()
Returns the depth of the hash computed byHashComputer.hash(double, double)
method.externalEdges
(long hash, int deltaDepth) void
externalEdges
(long hash, int toEdgeDeltaDepth, FlatHashList result) long
hash
(double lonRad, double latRad) Returns the HEALPix hash value of the given coordinate at this object depth.long
internalCorner
(long hash, int toEdgeDeltaDepth, CompassPoint.Cardinal direction) long
internalCornerE
(long hash, int toEdgeDeltaDepth) long
internalCornerN
(long hash, int toEdgeDeltaDepth) long
internalCornerS
(long hash, int toEdgeDeltaDepth) long
internalCornerW
(long hash, int toEdgeDeltaDepth) internalEdges
(long hash, int toEdgeDeltaDepth) void
internalEdges
(long hash, int toEdgeDeltaDepth, FlatHashList result) long
neighbour
(long hash, CompassPoint.MainWind direction) The hash value of the neighbour of the cell of given hash, in the given deirection.neighbours
(long hash) Returns the list of the hash of the cells surrounding the cell defined by the given hash.void
neighbours
(long hash, FlatHashList neighbours) Idem asNeighbourSelector.neighbours(long, NeighbourList)
except that the result is put in a simpleFlatHashList
.void
neighbours
(long hash, NeighbourList result) Equivalent ofNeighbourSelector.neighbours(long)
but passing in argument the list object to be filled.neighbours
(long hash, EnumSet<CompassPoint.MainWind> directions) Equivalent ofNeighbourSelector.neighbours(long, FlatHashList)
but with the list of direction of the wanted neighbours.void
neighbours
(long hash, EnumSet<CompassPoint.MainWind> directions, NeighbourList result) Equivalent ofNeighbourSelector.neighbours(long, FlatHashList)
but with the list of direction of the wanted neighbours.double[][]
pathAlongCellEdge
(long hash, CompassPoint.Cardinal startingVertex, boolean clockwiseDirection, int nSegmentsBySide) void
pathAlongCellEdge
(long hash, CompassPoint.Cardinal startingVertex, boolean clockwiseDirection, int nSegmentsBySide, double[][] pathPoints) double[][]
pathAlongCellSide
(long hash, CompassPoint.Cardinal fromVertex, CompassPoint.Cardinal toVertex, boolean isToVertexIncluded, int nSegments) Compute points on a given side of a given HEALPix cell on the unit sphere.void
pathAlongCellSide
(long hash, CompassPoint.Cardinal fromVertex, CompassPoint.Cardinal toVertex, boolean isToVertexIncluded, int nSegments, double[][] pathPoints) sortedExternalEdges
(long hash, int deltaDepth) void
sortedExternalEdges
(long hash, int toEdgeDeltaDepth, FlatHashList result) sortedInternalEdge
(long hash, int deltaDepth, CompassPoint.Ordinal direction) void
sortedInternalEdge
(long hash, int deltaDepth, CompassPoint.Ordinal direction, FlatHashList result) sortedInternalEdgeNE
(long hash, int deltaDepth) void
sortedInternalEdgeNE
(long hash, int deltaDepth, FlatHashList result) sortedInternalEdgeNW
(long hash, int deltaDepth) void
sortedInternalEdgeNW
(long hash, int deltaDepth, FlatHashList result) sortedInternalEdges
(long hash, int deltaDepth) void
sortedInternalEdges
(long hash, int toEdgeDeltaDepth, FlatHashList result) sortedInternalEdgeSE
(long hash, int deltaDepth) void
sortedInternalEdgeSE
(long hash, int deltaDepth, FlatHashList result) sortedInternalEdgeSW
(long hash, int deltaDepth) void
sortedInternalEdgeSW
(long hash, int deltaDepth, FlatHashList result) double[]
vertex
(long hash, CompassPoint.Cardinal cardinalPoint) Compute the position of an HEALPix cell vertex on the unit sphere.void
vertex
(long hash, CompassPoint.Cardinal vertexDirection, double[] resultLonLat) SeeVerticesAndPathComputer.vertex(long, Cardinal)
, except that the result is stored in the given array.void
vertices
(long hash, EnumMap<CompassPoint.Cardinal, double[]> cardinalPoints) EnumMap<CompassPoint.Cardinal,
double[]> vertices
(long hash, EnumSet<CompassPoint.Cardinal> cardinalPoints) Returns the vertices located at the given cardinal points.
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Field Details
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D0H_NEIGHBOURS
public static final byte[][] D0H_NEIGHBOURSFor each of the 12 hash of depth 0, contains the list of the depth 0 neighbours sorted by increasing hash value. -
NEIGHBOURS
public static final byte[][][] NEIGHBOURS
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Constructor Details
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HealpixNestedFast
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Method Details
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depth
public int depth()Description copied from interface:HashComputer
Returns the depth of the hash computed byHashComputer.hash(double, double)
method.- Specified by:
depth
in interfaceHashComputer
- Specified by:
depth
in interfaceHierarchyItem
- Returns:
- the depth of the hash computed by
HashComputer.hash(double, double)
method.
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hash
public long hash(double lonRad, double latRad) Description copied from interface:HashComputer
Returns the HEALPix hash value of the given coordinate at this object depth. WARNING: depending on the implementation, this method may or may not be thread-safe.- Specified by:
hash
in interfaceHashComputer
- Parameters:
lonRad
- longitude in radians, must support reasonably large positive and negative values producing accurate results with a naive range reduction like modulo 2*pi (i.e. without having to resort on Cody-Waite or Payne Hanek range reduction).latRad
- latitude in [-pi/2, pi/2] radians- Returns:
- the hash value associated to the given coordinate, at this object depth.
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center
public double[] center(long hash) Description copied from interface:VerticesAndPathComputer
Compute the position on the unit sphere of the center (in the Euclidean projection plane) of the cell associated to the given hash value.- Specified by:
center
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for the unprojected center- Returns:
- the unprojected position (on the unit sphere) of the center of the cell in the
Euclidean plane. The lon and lat coordinate are stored in the returned array at indices
VerticesAndPathComputer.LON_INDEX
andVerticesAndPathComputer.LAT_INDEX
respectively. Lat in [-pi/2, pi/2] radians, lon is in [0, 2pi] radians.
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center
public void center(long hash, double[] resultLonLat) Description copied from interface:VerticesAndPathComputer
SeeVerticesAndPathComputer.center(long)
, except that the result is stored in the given array.- Specified by:
center
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for the unprojected center.resultLonLat
- array used to store the result. Must be of size >= 2.
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vertex
Description copied from interface:VerticesAndPathComputer
Compute the position of an HEALPix cell vertex on the unit sphere.- Specified by:
vertex
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for the given vertex.cardinalPoint
- location of the vertex with respect to the cell center- Returns:
- the position (on the unit sphere) of the vertex located at the given cardinal direction
from the center of the given cell.
The lon and lat coordinate are stored in the returned array at indices
VerticesAndPathComputer.LON_INDEX
andVerticesAndPathComputer.LAT_INDEX
respectively. Lat is in [-pi/2, pi/2] radians, lon is in [0, 2pi] radians.
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vertex
Description copied from interface:VerticesAndPathComputer
SeeVerticesAndPathComputer.vertex(long, Cardinal)
, except that the result is stored in the given array.- Specified by:
vertex
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for the given vertex.vertexDirection
- location of the vertex with respect to the cell centerresultLonLat
- array used to store the result. Must be of size >= 2.
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vertices
public EnumMap<CompassPoint.Cardinal,double[]> vertices(long hash, EnumSet<CompassPoint.Cardinal> cardinalPoints) Description copied from interface:VerticesAndPathComputer
Returns the vertices located at the given cardinal points. If you want the full 4 vertices, simply useEnumSet.allOf(Cardinal)
. For West and East vertices, useEnumSet.of(Cardinal.W, Cardinal.E)
.- Specified by:
vertices
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for the given vertices.cardinalPoints
- locations of the vertices we look for the positions- Returns:
- the positions (on the unit sphere) of the vertices located at the given cardinal
directions from the center of the given cell.
The lon and lat coordinates of each vertex are stored in the arrays at indices
VerticesAndPathComputer.LON_INDEX
andVerticesAndPathComputer.LAT_INDEX
respectively. Lat is in [-pi/2, pi/2] radians, lon is in [0, 2pi] radians.
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vertices
Description copied from interface:VerticesAndPathComputer
SeeVerticesAndPathComputer.vertices(long, EnumSet)
. The difference is that the user provides a pre-set Map. The structure of the Map is not modified, but the coordinates of the values (array values) are overwritten. An error will be thrown if a value is null or contains less than two elements.- Specified by:
vertices
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for the given vertices.cardinalPoints
- the map to be modified y
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pathAlongCellSide
public double[][] pathAlongCellSide(long hash, CompassPoint.Cardinal fromVertex, CompassPoint.Cardinal toVertex, boolean isToVertexIncluded, int nSegments) Description copied from interface:VerticesAndPathComputer
Compute points on a given side of a given HEALPix cell on the unit sphere.- Specified by:
pathAlongCellSide
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for side path on the unit sphere.fromVertex
- direction (from the cell center) of the path starting vertextoVertex
- direction (from the cell center) of the path ending vertexisToVertexIncluded
- iffalse
, the result containsnSegments
points and do no include the result ending vertex. Else the result containsnSegments + 1
points.nSegments
- number of segments in the path from the starting vertex to the ending vertex- Returns:
- a list of points on the given side of the given HEALPix cell on the unit sphere.
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pathAlongCellSide
public void pathAlongCellSide(long hash, CompassPoint.Cardinal fromVertex, CompassPoint.Cardinal toVertex, boolean isToVertexIncluded, int nSegments, double[][] pathPoints) Description copied from interface:VerticesAndPathComputer
SeeVerticesAndPathComputer.pathAlongCellSide(long, Cardinal, Cardinal, boolean, int)
. The difference is that the user provides a list of points whose coordinates are going to be overwritten. An error will be thrown if the array (of array) is not large enough (i.e. its is smaller than nSegments or nSegments + 1) or if one of the array is null or contains less than two elements.- Specified by:
pathAlongCellSide
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for side path on the unit sphere.fromVertex
- direction (from the cell center) of the path starting vertextoVertex
- direction (from the cell center) of the path ending vertexisToVertexIncluded
- iffalse
, the result containsnSegments
points and do no include the result ending vertex. Else the result containsnSegments + 1
points.nSegments
- number of segments in the path from the starting vertex to the ending vertexpathPoints
- object used to store the result.
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pathAlongCellEdge
public double[][] pathAlongCellEdge(long hash, CompassPoint.Cardinal startingVertex, boolean clockwiseDirection, int nSegmentsBySide) - Specified by:
pathAlongCellEdge
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash value of the cell we look for the edge path on the unit sphere.startingVertex
- direction (from the cell center) of the path starting vertexclockwiseDirection
- iftrue
, result points are stored in a clockwise direction order, else they are stored in counter-clockwise direction order.nSegmentsBySide
- number of segments in each each side is divided. Hence, the total number of points in the result is4 x nSegmentsBySide
.- Returns:
- a list of points on the given edge of the given HEALPix cell on the unit sphere, clockwise or counter-clockwise ordered.
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pathAlongCellEdge
public void pathAlongCellEdge(long hash, CompassPoint.Cardinal startingVertex, boolean clockwiseDirection, int nSegmentsBySide, double[][] pathPoints) Description copied from interface:VerticesAndPathComputer
SeeVerticesAndPathComputer.pathAlongCellEdge(long, Cardinal, boolean, int)
. The difference is that the user provides a list of points whose coordinates are going to be overwritten. An error will be thrown if the array (of array) is not large enough (i.e. its is smaller than 4 *nSegments) or if one of the array is null or contains less than two elements.- Specified by:
pathAlongCellEdge
in interfaceVerticesAndPathComputer
- Parameters:
hash
- hash hash value of the cell we look for the edge path on the unit sphere.startingVertex
- direction (from the cell center) of the path starting vertexclockwiseDirection
- iftrue
, result points are stored in a clockwise direction order, else they are stored in counter-clockwise direction order.nSegmentsBySide
- number of segments in each each side is divided. Hence, the total number of points in the result is4 x nSegmentsBySide
.pathPoints
- object used to store the result.
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neighbours
Description copied from interface:NeighbourSelector
Idem asNeighbourSelector.neighbours(long, NeighbourList)
except that the result is put in a simpleFlatHashList
. WARNING: the content of the provided list is overwritten, and be sure the list is large enough (at least of size 8).- Specified by:
neighbours
in interfaceNeighbourSelector
- Parameters:
hash
- the hash code we want the neighboursneighbours
- which contains the list of neighbours from index 0 to the number of neighbours
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neighbour
Description copied from interface:NeighbourSelector
The hash value of the neighbour of the cell of given hash, in the given deirection.- Specified by:
neighbour
in interfaceNeighbourSelector
- Parameters:
hash
- ash value of the cell we are looking for the neighbour.direction
- direction of the neighbour we are looking for.- Returns:
- -1 if there is no neighbour in the given direction (hashes located at corners of base hases).
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neighbours
Description copied from interface:NeighbourSelector
Returns the list of the hash of the cells surrounding the cell defined by the given hash. The number of surrounding cells can be 8 (for all cells except the cells located at the corners of the 12 depth 0 cells), 7 (for the west and east corners of the polar caps, i.e. depth 0 cells number 0, 1, 2, 4, 8, 9, 10 and 11, or for the north and south corners of the equatorial regions, i.e. depth 0 cells number 4, 5, 6 and 7), or 6 for depth 0 pixels.- Specified by:
neighbours
in interfaceNeighbourSelector
- Parameters:
hash
- hash value of the cell we are looking for the neighbours.- Returns:
- the list of neighbours hashes
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neighbours
Description copied from interface:NeighbourSelector
Equivalent ofNeighbourSelector.neighbours(long, FlatHashList)
but with the list of direction of the wanted neighbours.- Specified by:
neighbours
in interfaceNeighbourSelector
- Parameters:
hash
- hash value of the cell we are looking for the neighbours.directions
- the directions of the neighbours we are looking for.- Returns:
- the list of the hash of the neighbours of the cell having the given hash.
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neighbours
Description copied from interface:NeighbourSelector
Equivalent ofNeighbourSelector.neighbours(long)
but passing in argument the list object to be filled. WARNING: the content of the provided list is overwritten, and be sure the list is large enough (at least of size 8). And the value -1 is returned if the given hash has no neighbour at the given main wind direction.- Specified by:
neighbours
in interfaceNeighbourSelector
- Parameters:
hash
- the hash code we want the neighboursresult
- which contains the list of neighbours from index 0 to the number of neighbours
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neighbours
Description copied from interface:NeighbourSelector
Equivalent ofNeighbourSelector.neighbours(long, FlatHashList)
but with the list of direction of the wanted neighbours. And the value -1 is returned if the given hash has no neighbour at the given main wind direction.- Specified by:
neighbours
in interfaceNeighbourSelector
- Parameters:
hash
- hash value of the cell we are looking for the neighbours.directions
- the directions of the neighbours we are looking for.result
- the list holding the result.
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internalEdges
- Specified by:
internalEdges
in interfaceNeighbourSelector
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internalEdges
- Specified by:
internalEdges
in interfaceNeighbourSelector
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sortedInternalEdges
- Specified by:
sortedInternalEdges
in interfaceNeighbourSelector
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sortedInternalEdges
- Specified by:
sortedInternalEdges
in interfaceNeighbourSelector
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sortedInternalEdge
- Specified by:
sortedInternalEdge
in interfaceNeighbourSelector
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sortedInternalEdge
public void sortedInternalEdge(long hash, int deltaDepth, CompassPoint.Ordinal direction, FlatHashList result) - Specified by:
sortedInternalEdge
in interfaceNeighbourSelector
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sortedInternalEdgeSE
- Specified by:
sortedInternalEdgeSE
in interfaceNeighbourSelector
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sortedInternalEdgeSE
- Specified by:
sortedInternalEdgeSE
in interfaceNeighbourSelector
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sortedInternalEdgeNE
- Specified by:
sortedInternalEdgeNE
in interfaceNeighbourSelector
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sortedInternalEdgeNE
- Specified by:
sortedInternalEdgeNE
in interfaceNeighbourSelector
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sortedInternalEdgeNW
- Specified by:
sortedInternalEdgeNW
in interfaceNeighbourSelector
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sortedInternalEdgeNW
- Specified by:
sortedInternalEdgeNW
in interfaceNeighbourSelector
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sortedInternalEdgeSW
- Specified by:
sortedInternalEdgeSW
in interfaceNeighbourSelector
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sortedInternalEdgeSW
- Specified by:
sortedInternalEdgeSW
in interfaceNeighbourSelector
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internalCorner
- Specified by:
internalCorner
in interfaceNeighbourSelector
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internalCornerN
public long internalCornerN(long hash, int toEdgeDeltaDepth) - Specified by:
internalCornerN
in interfaceNeighbourSelector
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internalCornerS
public long internalCornerS(long hash, int toEdgeDeltaDepth) - Specified by:
internalCornerS
in interfaceNeighbourSelector
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internalCornerE
public long internalCornerE(long hash, int toEdgeDeltaDepth) - Specified by:
internalCornerE
in interfaceNeighbourSelector
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internalCornerW
public long internalCornerW(long hash, int toEdgeDeltaDepth) - Specified by:
internalCornerW
in interfaceNeighbourSelector
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externalEdges
- Specified by:
externalEdges
in interfaceNeighbourSelector
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externalEdges
- Specified by:
externalEdges
in interfaceNeighbourSelector
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sortedExternalEdges
- Specified by:
sortedExternalEdges
in interfaceNeighbourSelector
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sortedExternalEdges
- Specified by:
sortedExternalEdges
in interfaceNeighbourSelector
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