cc.redberry.core.indices

Class IndicesUtils

java.lang.Object

cc.redberry.core.indices.IndicesUtils

public final class IndicesUtils
extends java.lang.Object

This class provides static methods to work with individual index and indices objects.

Index representation

All information about single index is enclosed in 32-bit word (int). The following bit structure is used:

 Index: stttttttXXXXXXXXcccccccccccccccc  -  per-bit representetion
 |       |       |       |      |
        31      23      15      7      0  -  bit index

 s - one bit representing index state (0 - lower; 1 - upper)
 t - 7-bits representing index type (lower latin, upper latin, etc...) [for concrete codes see below]
 c - code of concrete index (a - 0, b - 1, c - 2, etc...) [index name]
 X - reserved (always 0)

Index types

By default there are four different index types:

 

 
  
 
 HexCode 
 
 BitCode 
 
 Description 
 

   
 0x00 
   
 00000000 
   
 Latin lower case symbols 
 
 

   
 0x01 
   
 00000001 
   
 Latin upper case symbols 
 
 

   
 0x02 
   
 00000010 
   
 Greek lower case symbols 
 
 

   
 0x03 
   
 00000011 
   
 Greek upper case symbols 
 
 
 

Examples

Here are some examples of how concrete indices are presented in Redberry.

 

 
  
 
 Index 
 
 Hex 
 

   
 _a 
   
 0x00000000 
 
 

   
 _C 
   
 0x01000002 
 
 

   
 ^{\beta} 
   
 0x82000001 
 
 

   
 ^{\Chi} 
   
 0x83000015 
  
 
 

Since:

1.0

See Also:

Indices

Field Summary

Fields

Modifier and Type	Field and Description
static int	LOWER_RAW_STATE_INT Raw state int for lower indices
static int	UPPER_RAW_STATE_INT Raw state int for upper indices

Method Summary

Modifier and Type	Method and Description
static boolean	areContracted(int index0, int index1) Indicates whether two indices are contracted (has the same type & name but different states).
static boolean	containsNonMetric(Indices indices) Returns true if specified indices contain any index with non metric type.
static int	createIndex(int name, byte type, boolean state) Creates single index with specified name, type and state.
static int	createIndex(int name, IndexType type, boolean state) Creates single index with specified name, type and state.
static boolean	equalsRegardlessOrder(Indices indices1, int[] indices2)
static boolean	equalsRegardlessOrder(int[] indices1, int[] indices2)
static int[]	getFree(int[] indices) Returns an array of free indices only
static int[]	getIndicesNames(Indices indices) Returns an array of indices names (with types), presented in specified Indices object with the same ordering.
static int[]	getIndicesNames(int[] indices) Returns an array of indices names (with types)
static int[]	getIndicesNames(IntArray indices) Returns an array of indices names (with types)
static int[]	getIntersections(Indices u, Indices v) Returns an array of contracted indices between specified indices.
static int[]	getIntersections(int[] freeIndices1, int[] freeIndices2) Returns an array of contracted indices between specified free indices.
static int	getNameWithoutType(int index) Returns index name (code) without type.
static int	getNameWithType(int index) Returns index name (code) with type (first 30 bits), but without state bit (in other words with state bit set to zero).
static int	getRawStateInt(int index) Returns only state (31-th) bit of index without shift.
static int	getRawTypeInt(int index) Returns index type in form 0xxxxxxx000000000000000000000000, where x - type bits.
static int[]	getSortedDistinctIndicesNames(Indices indices) This method returns array of integers representing set of indices names present in the Indices object.
static boolean	getState(int index) Returns state (31-th) bit of index.
static int	getStateInt(int index) Returns state (31-th) bit of index shifted to 0-th position.
static byte	getType(int index) Returns index type.
static IndexType	getTypeEnum(int index) Returns index type enum value.
static int	getTypeInt(int index) Returns index type in form 0000000000000000000000000xxxxxxx, where x - type bits.
static byte	getTypeWithState(int index) Returns index type with state bit.
static boolean	hasEqualTypeAndName(int index0, int index1) Indicates whether two indices has the same type and name.
static boolean	hasEqualTypes(int index0, int index1) Indicates whether two indices has the same type.
static boolean	hasEqualTypesAndStates(int index0, int index1) Indicates whether two indices has the same type and state.
static boolean	haveEqualStates(int index1, int index2)
static boolean	haveIntersections(Indices u, Indices v) Returns true if at least one free index of u is contracted with some free index of v.
static int	inverseIndexState(int index) Returns index with inverse index state.
static boolean	isPermutationConsistentWithIndices(int[] indices, int[] permutation) This method checks whether specified permutation is consistent with specified indices.
static boolean	isPermutationConsistentWithIndices(int[] indices, Permutation permutation) This method checks whether specified permutation is consistent with specified indices.
static java.util.EnumSet<IndexType>	nonMetricTypes(Indices indices) Returns all non metric types that present in specified indices.
static int	parseIndex(java.lang.String string) Parse single index.
static int	setRawState(int rawState, int index) Changes index state to specified state of the form 0b1(0)000000.....
static int	setState(boolean state, int index) Changes index state to specified state (true - upper, false - lower).
static int	setType(byte type, int index) Changes index type to specified, represented by byte.
static int	setType(IndexType type, int index) Changes index type to specified, represented by byte.
static java.lang.String	toString(int index)
static java.lang.String	toString(int[] indices)
static java.lang.String	toString(int[] indices, OutputFormat mode)
static java.lang.String	toString(int index, OutputFormat mode)

Methods inherited from class java.lang.Object

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

Field Detail

UPPER_RAW_STATE_INT

public static final int UPPER_RAW_STATE_INT

Raw state int for upper indices

See Also:

Constant Field Values

LOWER_RAW_STATE_INT

public static final int LOWER_RAW_STATE_INT

Raw state int for lower indices

See Also:

Constant Field Values

Method Detail

createIndex

public static int createIndex(int name,
                              IndexType type,
                              boolean state)

Creates single index with specified name, type and state.

Parameters:

name - index name

type - index type

state - index state

Returns:

index

createIndex

public static int createIndex(int name,
                              byte type,
                              boolean state)

Creates single index with specified name, type and state.

Parameters:

name - index name

type - index type

state - index state

Returns:

index

getRawStateInt

public static int getRawStateInt(int index)

Returns only state (31-th) bit of index without shift.

Expression used by this method is: index & 0x80000000

Parameters:

index - index

Returns:

(1 << 31) for upper index & 0 for lower index

getStateInt

public static int getStateInt(int index)

Returns state (31-th) bit of index shifted to 0-th position.

Expression used by this method is: (index & 0x80000000) >>> 31

Parameters:

index - index

Returns:

1 for upper index & 0 for lower index

getState

public static boolean getState(int index)

Returns state (31-th) bit of index.

Expression used by this method is: (index & 0x80000000) == 0x80000000

Parameters:

index - index

Returns:

1 for upper index & 0 for lower index

inverseIndexState

public static int inverseIndexState(int index)

Returns index with inverse index state. So it raising lower indices and lowering upper indices.

Expression used by this method is: 0x80000000 ^ index

Parameters:

index - index

Returns:

index with inverse state bit

getNameWithType

public static int getNameWithType(int index)

Returns index name (code) with type (first 30 bits), but without state bit (in other words with state bit set to zero).

Expression used by this method is: index & 0x7FFFFFFF

Parameters:

index - specified index

Returns:

index name (code) with type (first 30 bits), but without state bit (in other words with state bit set to zero)

setType

public static int setType(byte type,
                          int index)

Changes index type to specified, represented by byte.

Expression used by this method is: (0x80FFFFFF & index) | ((0x7F & type) << 24)

Parameters:

type - type

index - index to change type in

Returns:

index with new type

setType

public static int setType(IndexType type,
                          int index)

Changes index type to specified, represented by byte.

Expression used by this method is: (0x80FFFFFF & index) | ((0x7F & type) << 24)

Parameters:

type - IndexType

index - index to change type in

Returns:

index with new type

setRawState

public static int setRawState(int rawState,
                              int index)

Changes index state to specified state of the form 0b1(0)000000.....

Expression used by this method is: rawState | index

Parameters:

rawState - raw state

index - index

Returns:

index with new state

setState

public static int setState(boolean state,
                           int index)

Changes index state to specified state (true - upper, false - lower).

Parameters:

state - index state: true - upper, false - lower)

index - index to change type in

Returns:

index with new state

getNameWithoutType

public static int getNameWithoutType(int index)

Returns index name (code) without type.

Expression used by this method is: index & 0xFFFF

Parameters:

index - index

Returns:

index name

getType

public static byte getType(int index)

Returns index type.

Expression used by this method is: ((byte) ((index & 0x7FFFFFFF) >>> 24))

Parameters:

index - index

Returns:

index type

getTypeEnum

public static IndexType getTypeEnum(int index)

Returns index type enum value.

Parameters:

index - index

Returns:

index type enum value

getTypeInt

public static int getTypeInt(int index)

Returns index type in form 0000000000000000000000000xxxxxxx, where x - type bits.

Expression used by this method is: (index & 0x7FFFFFFF) >>> 24

Parameters:

index - index

Returns:

index type

getRawTypeInt

public static int getRawTypeInt(int index)

Returns index type in form 0xxxxxxx000000000000000000000000, where x - type bits.

Expression used by this method is: index & 0x7F000000

Parameters:

index - index

Returns:

index type

getTypeWithState

public static byte getTypeWithState(int index)

Returns index type with state bit.

Expression used by this method is: ((byte) (index >>> 24))

Parameters:

index - index

Returns:

index type with state

hasEqualTypeAndName

public static boolean hasEqualTypeAndName(int index0,
                                          int index1)

Indicates whether two indices has the same type and name.

Expression used by this method is: (index0 & 0x7FFFFFFF) == (index1 & 0x7FFFFFFF)

Parameters:

index0 - first index

index1 - second index

Returns:

whether all bits except state bit are equals

hasEqualTypes

public static boolean hasEqualTypes(int index0,
                                    int index1)

Indicates whether two indices has the same type.

Expression used by this method is: (index0 & 0x7F000000) == (index1 & 0x7F000000)

Parameters:

index0 - first index

index1 - second index

Returns:

true if type bits in indices are the same

hasEqualTypesAndStates

public static boolean hasEqualTypesAndStates(int index0,
                                             int index1)

Indicates whether two indices has the same type and state.

Expression used by this method is: (index0 & 0xFF000000) == (index1 & 0xFF000000)

Parameters:

index0 - first index

index1 - second index

Returns:

true if type and state bits in indices are the same

areContracted

public static boolean areContracted(int index0,
                                    int index1)

Indicates whether two indices are contracted (has the same type & name but different states).

This method is very fast, because it performs only two operations: bitwise xor + testing for equality with 32-bit constant.
Expression used by this method is: (index0 ^ index1) == 0x80000000

Parameters:

index0 - first index

index1 - second index

Returns:

true if type and state bits in indices are the same

getSortedDistinctIndicesNames

public static int[] getSortedDistinctIndicesNames(Indices indices)

This method returns array of integers representing set of indices names present in the Indices object.

Parameters:

indices - object to process

Returns:

see description

toString

public static java.lang.String toString(int index,
                                        OutputFormat mode)

toString

public static java.lang.String toString(int index)

toString

public static java.lang.String toString(int[] indices,
                                        OutputFormat mode)

toString

public static java.lang.String toString(int[] indices)

parseIndex

public static int parseIndex(java.lang.String string)

Parse single index.

Parameters:

string - string representation of index

Returns:

integer representation of index

getIndicesNames

public static int[] getIndicesNames(Indices indices)

Returns an array of indices names (with types), presented in specified Indices object with the same ordering.

Parameters:

indices -

Returns:

array of indices names (with types)

getIndicesNames

public static int[] getIndicesNames(int[] indices)

Returns an array of indices names (with types)

Parameters:

indices -

Returns:

array of indices names (with types)

getIndicesNames

public static int[] getIndicesNames(IntArray indices)

Returns an array of indices names (with types)

Parameters:

indices -

Returns:

array of indices names (with types)

getFree

public static int[] getFree(int[] indices)

Returns an array of free indices only

Parameters:

indices -

Returns:

array of free indices only

haveEqualStates

public static boolean haveEqualStates(int index1,
                                      int index2)

isPermutationConsistentWithIndices

public static boolean isPermutationConsistentWithIndices(int[] indices,
                                                         int[] permutation)

This method checks whether specified permutation is consistent with specified indices. Permutation considered to be consistent if it has similar length and does not permutes indices with different types.

Parameters:

indices - indices array to be checked

permutation - permutation in one-line notation

Returns:

false if permutation permutes indices with different types or have different length and true in other case

isPermutationConsistentWithIndices

public static boolean isPermutationConsistentWithIndices(int[] indices,
                                                         Permutation permutation)

This method checks whether specified permutation is consistent with specified indices. Permutation considered to be consistent if it has similar length and does not permutes indices with different types.

Parameters:

indices - indices array to be checked

permutation - permutation in one-line notation

Returns:

false if permutation permutes indices with different types or have different length and true in other case

equalsRegardlessOrder

public static boolean equalsRegardlessOrder(Indices indices1,
                                            int[] indices2)

equalsRegardlessOrder

public static boolean equalsRegardlessOrder(int[] indices1,
                                            int[] indices2)

haveIntersections

public static boolean haveIntersections(Indices u,
                                        Indices v)

Returns true if at least one free index of u is contracted with some free index of v.

Parameters:

u - indices

v - indices

Returns:

true if at least one free index of u is contracted with some free index of v

getIntersections

public static int[] getIntersections(int[] freeIndices1,
                                     int[] freeIndices2)

Returns an array of contracted indices between specified free indices.

Parameters:

freeIndices1 - free indices

freeIndices2 - free indices

Returns:

an array of contracted indices

getIntersections

public static int[] getIntersections(Indices u,
                                     Indices v)

Returns an array of contracted indices between specified indices.

Parameters:

u - indices

v - indices

Returns:

an array of contracted indices

containsNonMetric

public static boolean containsNonMetric(Indices indices)

Returns true if specified indices contain any index with non metric type.

Parameters:

indices - indices

Returns:

true if specified indices contain any index with non metric type

nonMetricTypes

public static java.util.EnumSet<IndexType> nonMetricTypes(Indices indices)

Returns all non metric types that present in specified indices.

Parameters:

indices - indices

Returns:

all non metric types that present in specified indices