cds.healpix

Class HealpixNestedBMOC

java.lang.Object

cds.healpix.HealpixNestedBMOC

All Implemented Interfaces:

java.lang.Iterable<HealpixNestedBMOC.CurrentValueAccessor>

public final class HealpixNestedBMOC
extends java.lang.Object
implements java.lang.Iterable<HealpixNestedBMOC.CurrentValueAccessor>

A BMOC is a MOC storing for each element a binary value telling if the cell is PARTIALY or FULLY covered by a region.
Internally, a long is made of bits:
BBBBxx...xxS00...00F if depth < depthMax
BBBBxx...xxxx...xxSF if depth = dephtMax
With:

• B: the 4 bits coding the base hash [0- 11]
• xx: the 2 bits of level x
• S: the sentinel bit coding the depth
• 00: if (depth != depthMax) those bits are unused bits
• F; the flag bit (0: partial, 1: full)

WARNING: not tested yet at depth 29, may not work because of Java signed long (all 64 bits of a long are used: 62 + 1 sentinel + 1 flag)

Author:

F.-X. Pineau

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	HealpixNestedBMOC.CurrentValueAccessor Provides informations on the current element of the BMOC while iterating over it.
static class	HealpixNestedBMOC.Status Tells if an element of the MOC is covered or not by a region and, if covered, it tells is the element is partially or fully covered.

Method Summary

Modifier and Type	Method and Description
static long	buildValue(int depth, long hash, boolean isFull, int depthMax) Creates a specific hash encoding the hash value at the given depth, the depth and the status flag.
long	computeDeepSize() Returns the number of cells at depth getDepthMax() the moc contains, i.e.
static HealpixNestedBMOC	createCheck(int mocDepth, long[] mocCells) Same a createUnsafe(int, long[]) except that the properties (array sorted, no duplicates, no cell included into an other one) is checked.
static HealpixNestedBMOC	createCheck(int mocDepth, long[] mocCells, int toIndex) Same as createCheck(int, long[]) except that not we do not use the full array.
static HealpixNestedBMOC	createPacking(int mocDepth, long[] mocCells)
static HealpixNestedBMOC	createPacking(int mocDepth, long[] mocCells, int toIndex) We assume here that the given array is ordered, that no element overlaps another one, but that the MOC is not normalized, i.e. a large cell may be splitted in 4 sub-cell (each sub-cell possibly splitted in its 4 sub-cells recursively).
static HealpixNestedBMOC	createUnsafe(int mocDepth, long[] mocCells) Create a MOC considering that the given array is already a MOC: i.e. it is sorted (ASC order) and do not contains duplicate or small cells included into larger one's.
static HealpixNestedBMOC	createUnsafe(int mocDepth, long[] mocCells, int toIndex) Same as createUnsafe(int, long[]) except that not we do not use the full array.
FlatHashIterator	flatHashIterator() Returns an iterator on all the cells in the BMOC at the maximum depth.
int	getDepthMax() Returns the BMOC deeper depth.
java.util.Iterator<HealpixNestedBMOC.CurrentValueAccessor>	iterator()
int	size() Returns the number of elements the moc contains, i.e. the number of cells at various depth.
HealpixNestedBMOC.Status	statut(int depth, long hash) Returns the status of the given hash at the given depth
HealpixNestedBMOC	toDeeperDepth(int newDepth) Returns a new BMOC having a deeper depth.
HealpixNestedBMOC	toLowerDepth(int newDepth)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

toDeeperDepth

public HealpixNestedBMOC toDeeperDepth(int newDepth)

Returns a new BMOC having a deeper depth.

Parameters:

newDepth - the depeht of the wanted new BMOC

Returns:

a new BMOC having a deeper depth.

toLowerDepth

public HealpixNestedBMOC toLowerDepth(int newDepth)

size

public int size()

Returns the number of elements the moc contains, i.e. the number of cells at various depth.

Returns:

the number of elements the moc contains, i.e. the number of cells at various depth.

computeDeepSize

public long computeDeepSize()

Returns the number of cells at depth getDepthMax() the moc contains, i.e. the sum for each cell of the number of cells at depth getDepthMax().

Returns:

the number of cells at depth getDepthMax() the moc contains, i.e. the sum for each cell of the number of cells at depth getDepthMax().

createUnsafe

public static HealpixNestedBMOC createUnsafe(int mocDepth,
                                             long[] mocCells)

Create a MOC considering that the given array is already a MOC: i.e. it is sorted (ASC order) and do not contains duplicate or small cells included into larger one's. WARNING: the array is used internally, so it must not be modified by an external reference! use Arrays.copy() is you are not sure!

Parameters:

mocDepth - the depth of the MOC

mocCells - the array representation of the MOC

Returns:

the MOC object storing internally the array

createUnsafe

public static HealpixNestedBMOC createUnsafe(int mocDepth,
                                             long[] mocCells,
                                             int toIndex)

Same as createUnsafe(int, long[]) except that not we do not use the full array.

Parameters:

mocDepth - the depth of the MOC

mocCells - the array representation of the MOC

toIndex - the index of the last element (exclusive) to be considered in the moc

Returns:

the MOC object storing internally the array

createCheck

public static HealpixNestedBMOC createCheck(int mocDepth,
                                            long[] mocCells)

Same a createUnsafe(int, long[]) except that the properties (array sorted, no duplicates, no cell included into an other one) is checked.

Parameters:

mocDepth - the depth of the MOC

mocCells - the array representation of the MOC

Returns:

the MOC object storing internally the array

createCheck

public static HealpixNestedBMOC createCheck(int mocDepth,
                                            long[] mocCells,
                                            int toIndex)

Same as createCheck(int, long[]) except that not we do not use the full array.

Parameters:

mocDepth - the depth of the MOC

mocCells - the array representation of the MOC

toIndex - the index of the last element (exclusive) to be considered in the moc

Returns:

the MOC object storing internally the array

createPacking

public static HealpixNestedBMOC createPacking(int mocDepth,
                                              long[] mocCells)

createPacking

public static HealpixNestedBMOC createPacking(int mocDepth,
                                              long[] mocCells,
                                              int toIndex)

We assume here that the given array is ordered, that no element overlaps another one, but that the MOC is not normalized, i.e. a large cell may be splitted in 4 sub-cell (each sub-cell possibly splitted in its 4 sub-cells recursively).

Parameters:

mocDepth - depth of the moc

mocCells - ordered list of cells

toIndex - index of the last cell to be read in the given array of cells

Returns:

a new moc from the input parameters, packing if necessary.

getDepthMax

public int getDepthMax()

Returns the BMOC deeper depth.

Returns:

the BMOC deeper depth.

statut

public HealpixNestedBMOC.Status statut(int depth,
                                       long hash)

Returns the status of the given hash at the given depth

Parameters:

depth - depth of the hash we want the status

hash - hash for which we want the status

Returns:

the status of the given hash at the given depth

buildValue

public static final long buildValue(int depth,
                                    long hash,
                                    boolean isFull,
                                    int depthMax)

Creates a specific hash encoding the hash value at the given depth, the depth and the status flag.

Parameters:

depth - depth of the hash.

hash - value of the hash.

isFull - flag telling if the cell is fully covered or not.

depthMax - maximum depth of the MOC the value will belong to.

Returns:

a BMOC encoded hash value with its depth and status flag.

iterator

public java.util.Iterator<HealpixNestedBMOC.CurrentValueAccessor> iterator()

Specified by:

iterator in interface java.lang.Iterable<HealpixNestedBMOC.CurrentValueAccessor>

flatHashIterator

public FlatHashIterator flatHashIterator()

Returns an iterator on all the cells in the BMOC at the maximum depth.

Returns:

an iterator on all the cells in the BMOC at the maximum depth.