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java.lang.Objectuk.ac.starlink.table.join.SkyMatchEngine
uk.ac.starlink.table.join.HTMMatchEngine
public class HTMMatchEngine
Implements the object matching interface for sky coordinates using the HTM (Hierarchical Triangular Mesh) pixel-indexing scheme.
Note that the HEALPixMatchEngine
implementation normally gives
much faster matching than this and should generally be used in
preference.
Field Summary | |
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static double |
MESH_SCALE
Scaling factor which determines the size of the mesh cells used as a multiple of the size of the separation. |
Fields inherited from interface uk.ac.starlink.table.join.MatchEngine |
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NO_BINS |
Constructor Summary | |
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HTMMatchEngine(double separation,
boolean useErrors)
Constructs a new match engine which considers two points (RA,Dec tuples) to match if they are within a given angular distance on the celestial sphere. |
Method Summary | |
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int |
calculateDefaultLevel(double sep)
Determines a default value to use for the level paramer based on a given separation. |
Object[] |
getBins(double ra,
double dec,
double err)
Returns all the HTM cells which fall wholly or partially within err radians of a given position. |
int |
getLevel()
Returns the HTM level, which determines sky pixel size. |
DescribedValue[] |
getTuningParameters()
Returns a set of DescribedValue objects whose values can be modified to tune the performance of the match. |
void |
setLevel(int level)
Sets the HTM level value, which determines sky pixel size. |
void |
setSeparation(double separation)
Configures this match engine to consider two points (RA,Dec tuples) to match if they are within a given angular distance on the celestial sphere. |
Methods inherited from class uk.ac.starlink.table.join.SkyMatchEngine |
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calculateSeparation, canBoundMatch, getBins, getMatchBounds, getMatchParameters, getMatchScoreInfo, getSeparation, getTupleInfos, getUseErrors, matchScore, setUseErrors, toString |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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public static final double MESH_SCALE
Constructor Detail |
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public HTMMatchEngine(double separation, boolean useErrors)
separation
- match radius in radiansuseErrors
- if true, per-row errors can be specified as
a third element of the tuples; otherwise only the fixed
separation value countsMethod Detail |
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public void setSeparation(double separation)
SkyMatchEngine
setSeparation
in class SkyMatchEngine
separation
- match radius in radianspublic Object[] getBins(double ra, double dec, double err)
getBins
in class SkyMatchEngine
ra
- right ascensiondec
- declinationerr
- error
SkyMatchEngine.getBins(java.lang.Object[])
public DescribedValue[] getTuningParameters()
MatchEngine
DescribedValue.setValue(java.lang.Object)
on the
returned objects.
Changing these values will make no difference to the output of
MatchEngine.matchScore(java.lang.Object[], java.lang.Object[])
, but may change the output of MatchEngine.getBins(java.lang.Object[])
.
This may change the CPU and memory requirements of the match,
but will not change the result. The default value should be
something sensible, so that setting the value of these parameters
is not in general required.
public void setLevel(int level)
level
- new level valuepublic int getLevel()
public int calculateDefaultLevel(double sep)
sep
- max sky separation angle for a match, in radians
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Copyright © 2004 CLRC: Central Laboratory of the Research Councils. All rights reserved. | ||||||||
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