org.colomoto.mddlib.internal

Class MDDStoreImpl

java.lang.Object

org.colomoto.mddlib.internal.MDDStoreImpl

All Implemented Interfaces:

MDDStore, MDDManager

public class MDDStoreImpl
extends Object
implements MDDStore

MDD factory implementation: create, store, retrieve a collection of MDDs.

The number of leaves is defined upon creation and can not be changed.

MDDs are stored in a large integer array, divided into blocs. Each bloc denotes a MDD node, providing its level and list of children, as well as the reference counter. To avoid duplication, a hashmap allows to find existing nodes quickly. New nodes are added by extending the storage array, but blocs can also be freed when unused. A chained list allows to reuse these free blocs.

Author:

Aurelien Naldi

See Also:

for further details.

Field Summary

Fields

Modifier and Type	Field and Description
protected MDDVariable[]	variables

Constructor Summary

Constructors

Constructor and Description
MDDStoreImpl(Collection<?> keys, int nbleaves) Create a new MDDStore using the default capacity.

Method Summary

Modifier and Type	Method and Description
boolean[]	collectDecisionVariables(int node) Collect variables on which a MDD depends.
void	debug() print raw data structure (hashcodes, hashitems and data blocs).
String	dumpMDD(int mdd) Write a raw text representation of the MDD
MDDVariable	ensureVariable(Object key, byte nbval) get a variable, create it if needed.
void	free(int pos) Free a node.
MDDVariable[]	getAllVariables() Get all MDDVariables in this manager.
int	getChild(int id, int value) Get a specific child for a node.
int[]	getChildren(int node) Get all the children of a given node.
int	getLeafCount() Get the number of leaves
MDDManager	getManager(List<?> order) Get a new manager for this MDD Store, using a custom variable order.
VariableEffect[]	getMultivaluedVariableEffect(MDDVariable var, int node) Determine the effect of a given variable on a MDD.
int	getNode(int var, int[] children) Retrieve or create a node in the backend.
int	getNode(int var, int lchild, int rchild) Retrieve or create a node in the backend.
int	getNodeCount()
MDDVariable	getNodeVariable(int n) Get the variable associated to a given node.
NodeRelation	getRelation(int first, int other) Determine the relation between two nodes.
int	getSign(int node, MDDVariable pivot) Infer the effect of a variable in a given MDD.
VariableEffect	getVariableEffect(MDDVariable var, int node) Determine the effect of a given variable on a MDD.
MDDVariable	getVariableForKey(Object key) Get the MDDVariable associated to a given key.
int	getVariableIndex(MDDVariable var) Get the position of a given variable in this manager's list of variables.
byte	groupReach(int node, byte[] values) Get the value reached by a group of paths.
byte	groupReach(int node, byte[] values, int[] orderMap) Find the leaf reached for a given group of variable assignment and custom order.
boolean	isleaf(int id)
boolean	isView(MDDManager ddm)
int	mnot(int node, int v) Multi-valued not: flip leaves 0 and v.
int	nodeFromState(byte[] state, int value) Create a MDD representing a state.
int	nodeFromState(byte[] state, int value, int[] orderMap) Helper to build a node from a state in proxy views.
int	nodeFromStates(Collection<byte[]> states, int value) Create a MDD representing a group of states.
int	not(int node) Logical not, performed by flipping leaves 0 and 1.
int	parseDump(String s) Create a MDD from a dumped structure
void	printNode(int node) Debug helper: print a MDD on standard output.
byte	reach(int node, byte[] values) Find the leaf reached for a given variable assignment
byte	reach(int node, byte[] values, int[] orderMap) Find the leaf reached for a given variable assignment and custom order.
int	use(int node) Mark a node as used.

Methods inherited from class java.lang.Object

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

Field Detail

variables

protected MDDVariable[] variables

Constructor Detail

MDDStoreImpl

public MDDStoreImpl(Collection<?> keys,
                    int nbleaves)

Create a new MDDStore using the default capacity. Note that this constructor should be called through MDDManagerFactory, not directly.

Parameters:

keys - the list of variables that can be used.

nbleaves - the number of values that can be reached.

Method Detail

getManager

public MDDManager getManager(List<?> order)

Description copied from interface: MDDManager

Get a new manager for this MDD Store, using a custom variable order. The new manager will use the same MDDStore as backend: it is just a different view of the same MDD dataset.

Specified by:

getManager in interface MDDManager

Parameters:

order - requested variable order.

Returns:

a new manager (this if the order is the same)

getNodeVariable

public MDDVariable getNodeVariable(int n)

Description copied from interface: MDDManager

Get the variable associated to a given node.

Specified by:

getNodeVariable in interface MDDManager

Parameters:

n - the node ID

Returns:

the variable of null if the node is a leaf.

getVariableIndex

public int getVariableIndex(MDDVariable var)

Description copied from interface: MDDManager

Get the position of a given variable in this manager's list of variables.

Specified by:

getVariableIndex in interface MDDManager

Returns:

the position in getAllVariables().

getVariableForKey

public MDDVariable getVariableForKey(Object key)

Description copied from interface: MDDManager

Get the MDDVariable associated to a given key.

Specified by:

getVariableForKey in interface MDDManager

Returns:

the associated MDDVariable

ensureVariable

public MDDVariable ensureVariable(Object key,
                                  byte nbval)

Description copied from interface: MDDManager

get a variable, create it if needed.

Specified by:

ensureVariable in interface MDDManager

Returns:

getAllVariables

public MDDVariable[] getAllVariables()

Description copied from interface: MDDManager

Get all MDDVariables in this manager.

Specified by:

getAllVariables in interface MDDManager

Returns:

the ordered list of available MDDVariables.

getNode

public int getNode(int var,
                   int lchild,
                   int rchild)

Description copied from interface: MDDStore

Retrieve or create a node in the backend. This is called by MDDVariable.getNode() or by internal store methods: it should not be used directly.

Specified by:

getNode in interface MDDStore

Returns:

the index of the requested node

getNode

public int getNode(int var,
                   int[] children)

Description copied from interface: MDDStore

Retrieve or create a node in the backend. This is called by MDDVariable.getNode() or by internal store methods: it should not be used directly.

Specified by:

getNode in interface MDDStore

Returns:

the index of the requested node

use

public int use(int node)

Description copied from interface: MDDManager

Mark a node as used. This is done automatically when creating or reusing a node. In most cases, manually calling this should not be necessary. If you do call it, remember to call free(int) when you release it.

Specified by:

use in interface MDDManager

Returns:

the ID of the node (yes, the same as the parameter, just as convenience)

free

public void free(int pos)

Description copied from interface: MDDManager

Free a node. If it is not used at all anymore, it will be removed from the data structure.

This should be used for each node id that was obtained through one of the get_?node() method, or for the one explicitly marked as used.

Note that the space will be made available for new nodes, but it will NOT be returned to the garbage collector.

Specified by:

free in interface MDDManager

See Also:

use(int), get_bnode(int, int, int), get_mnode(int, int[])

not

public int not(int node)

Description copied from interface: MDDManager

Logical not, performed by flipping leaves 0 and 1.

Specified by:

not in interface MDDManager

Returns:

the ID of the flipped MDD root

mnot

public int mnot(int node,
                int v)

Description copied from interface: MDDManager

Multi-valued not: flip leaves 0 and v.

Specified by:

mnot in interface MDDManager

v - the positive value

Returns:

getRelation

public NodeRelation getRelation(int first,
                                int other)

Description copied from interface: MDDManager

Determine the relation between two nodes. Mainly used by operators to select the appropriate code path.

Specified by:

getRelation in interface MDDManager

Returns:

an NodeRelation value denoting which node is a leaf or has the highest ranked variable

getNodeCount

public int getNodeCount()

Specified by:

getNodeCount in interface MDDManager

Returns:

the number of non-leaf nodes stored in the manager.

getLeafCount

public int getLeafCount()

Description copied from interface: MDDManager

Get the number of leaves

Specified by:

getLeafCount in interface MDDManager

Returns:

the number of possible leaves (i.e. max leaf index)

isleaf

public boolean isleaf(int id)

Specified by:

isleaf in interface MDDManager

Parameters:

id - the ID of the tested node.

Returns:

true if id denotes a leaf in this manager

getChild

public int getChild(int id,
                    int value)

Description copied from interface: MDDManager

Get a specific child for a node. Note: the child is not counted as used, do not free it (or call manager.use() before)

Specified by:

getChild in interface MDDManager

Parameters:

id - id of a node

value - assignment value

Returns:

the id of the child node reached when assigning this value to the variable of the provided node.

getChildren

public int[] getChildren(int node)

Description copied from interface: MDDManager

Get all the children of a given node. Node: this will create a new array to hold the children. Children are not counted as used, do not free them (or call manager.use() before)

Specified by:

getChildren in interface MDDManager

Returns:

an array holding all the children, or null if it is a leaf.

reach

public byte reach(int node,
                  byte[] values)

Description copied from interface: MDDManager

Find the leaf reached for a given variable assignment

Specified by:

reach in interface MDDManager

Returns:

the leaf reached for this assignment

reach

public byte reach(int node,
                  byte[] values,
                  int[] orderMap)

Description copied from interface: MDDStore

Find the leaf reached for a given variable assignment and custom order. This is used by proxy MDDManager to implement reach(int byte[])

Specified by:

reach in interface MDDStore

Returns:

the reached leaf

groupReach

public byte groupReach(int node,
                       byte[] values)

Description copied from interface: MDDManager

Get the value reached by a group of paths.

Specified by:

groupReach in interface MDDManager

Returns:

the leaf reached for this assignment

groupReach

public byte groupReach(int node,
                       byte[] values,
                       int[] orderMap)

Description copied from interface: MDDStore

Find the leaf reached for a given group of variable assignment and custom order. This is used by proxy MDDManager to implement groupReach(int byte[])

Specified by:

groupReach in interface MDDStore

Returns:

the reached leaf

getSign

public int getSign(int node,
                   MDDVariable pivot)

Description copied from interface: MDDManager

Infer the effect of a variable in a given MDD.

Specified by:

getSign in interface MDDManager

Parameters:

node - the MDD

pivot - the variable of interest

Returns:

0 for no effect, 1 for positive effect, -1 for negative effect or 2 for dual effect

collectDecisionVariables

public boolean[] collectDecisionVariables(int node)

Description copied from interface: MDDManager

Collect variables on which a MDD depends.

Specified by:

collectDecisionVariables in interface MDDManager

Returns:

a boolean array indicating for each variable if it affects the given MDD.

getVariableEffect

public VariableEffect getVariableEffect(MDDVariable var,
                                        int node)

Description copied from interface: MDDManager

Determine the effect of a given variable on a MDD. To find variables of interest, use collectDecisionVariables(node).

Specified by:

getVariableEffect in interface MDDManager

Returns:

the effect of this variable.

getMultivaluedVariableEffect

public VariableEffect[] getMultivaluedVariableEffect(MDDVariable var,
                                                     int node)

Description copied from interface: MDDManager

Determine the effect of a given variable on a MDD. To find variables of interest, use collectDecisionVariables(node).

Specified by:

getMultivaluedVariableEffect in interface MDDManager

Returns:

the effects of each level switch for this variable

printNode

public void printNode(int node)

Debug helper: print a MDD on standard output.

Parameters:

node - the node index

debug

public void debug()

print raw data structure (hashcodes, hashitems and data blocs). A must if you enjoy reading boring series of numbers.

isView

public boolean isView(MDDManager ddm)

Specified by:

isView in interface MDDManager

nodeFromState

public int nodeFromState(byte[] state,
                         int value)

Description copied from interface: MDDManager

Create a MDD representing a state.

Specified by:

nodeFromState in interface MDDManager

Returns:

nodeFromStates

public int nodeFromStates(Collection<byte[]> states,
                          int value)

Description copied from interface: MDDManager

Create a MDD representing a group of states.

Specified by:

nodeFromStates in interface MDDManager

Returns:

nodeFromState

public int nodeFromState(byte[] state,
                         int value,
                         int[] orderMap)

Description copied from interface: MDDStore

Helper to build a node from a state in proxy views.

Specified by:

nodeFromState in interface MDDStore

Returns:

dumpMDD

public String dumpMDD(int mdd)

Description copied from interface: MDDManager

Write a raw text representation of the MDD

Specified by:

dumpMDD in interface MDDManager

Returns:

a string representing the MDD structure

parseDump

public int parseDump(String s)
              throws ParseException

Description copied from interface: MDDManager

Create a MDD from a dumped structure

Specified by:

parseDump in interface MDDManager

Parameters:

s - the string representing the MDD structure

Returns:

the corresponding MDD

Throws:

ParseException