net.sourceforge.czt.animation.eval.flatpred

Class FlatMember

java.lang.Object

net.sourceforge.czt.animation.eval.flatpred.FlatPred

net.sourceforge.czt.animation.eval.flatpred.FlatMember

public class FlatMember
extends FlatPred

Author:

Mark Utting FlatMember(s,e) implements e \in s, where s can be any kind of set that implements the EvalSet interface.

Field Summary

Fields

Modifier and Type	Field and Description
protected Bounds	bounds_ The most recent variable bounds information.
protected Iterator<net.sourceforge.czt.z.ast.Expr>	current_ This is for iterating through set_
protected EvalSet	set_ This is non_null during evaluation

Fields inherited from class net.sourceforge.czt.animation.eval.flatpred.FlatPred

args_, evalMode_, freeVars_, INDENT, LOG, printer_, solutionsReturned_

Constructor Summary

Constructors

Constructor and Description
FlatMember(net.sourceforge.czt.z.ast.ZName set, net.sourceforge.czt.z.ast.ZName element) Membership of a set.

Method Summary

Modifier and Type	Method and Description
<R> R	accept(net.sourceforge.czt.util.Visitor<R> visitor) Calls visitor.visitPred (preferably) or visitor.visitTerm.
Mode	chooseMode(Envir env) Choose the mode that this predicate could use in this environment.
protected double	estSize(Envir env) Returns all known information about the maximum size of the set, for the given membership request.
boolean	inferBounds(Bounds bnds) Infer bounds for any integer variables.
protected Map<Object,net.sourceforge.czt.z.ast.Expr>	knownValues(Envir env) Returns the set of arguments that already have known values.
boolean	nextEvaluation() Generates the next solution that satisfies this predicate.
protected RangeSet	range(Envir env) Returns all known information about the range of integer members, if this set happens to contain integers.
void	startEvaluation()
String	toString() Prints the FlatMember with optional bounds information.

Methods inherited from class net.sourceforge.czt.animation.eval.flatpred.FlatPred

freeVars, getArgs, getEnvir, getLastArg, getMode, indent, modeAllDefined, modeCollection, modeFunction, modeOneOutput, printArg, printBinOp, printLastArg, printName, printQuant, setMode

Methods inherited from class java.lang.Object

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

Field Detail

bounds_

protected Bounds bounds_

The most recent variable bounds information.

set_

protected EvalSet set_

This is non_null during evaluation

current_

protected Iterator<net.sourceforge.czt.z.ast.Expr> current_

This is for iterating through set_

Constructor Detail

FlatMember

public FlatMember(net.sourceforge.czt.z.ast.ZName set,
                  net.sourceforge.czt.z.ast.ZName element)

Membership of a set.

Parameters:

set - Must evaluate to an EvalSet object.

element - The member of the set.

Method Detail

inferBounds

public boolean inferBounds(Bounds bnds)

Description copied from class: FlatPred

Infer bounds for any integer variables. This analyzes the possible range of values of each integer variable used by this FlatPred, and reduces the range of values if possible. This is a kind of static analysis commonly used in constraint solvers (bounds consistency). For example, if y already has the range 10..20, then the FlatPred x < y would set the maximum value of x to 19.

Overrides:

inferBounds in class FlatPred

Parameters:

bnds - The database of lower and upper bounds for integer variables.

Returns:

true iff the bnds database has been changed.

The default implementation infers nothing and returns false.

knownValues

protected Map<Object,net.sourceforge.czt.z.ast.Expr> knownValues(Envir env)

Returns the set of arguments that already have known values. (though the values may be null at chooseMode time).

Parameters:

env - The environment in which to look for the values

Returns:

null if no args are known.

range

protected RangeSet range(Envir env)

Returns all known information about the range of integer members, if this set happens to contain integers. It returns null if nothing is known, or the set does not contain integers.

Parameters:

env - Optional environment that will be used to evaluate the set

Returns:

estSize

protected double estSize(Envir env)

Returns all known information about the maximum size of the set, for the given membership request. This uses range information from static bounds checking and from the set itself. It can be called at any time, but will give more accurate estimates as more becomes known.

Parameters:

env - Optional environment that will be used to evaluate the set

Returns:

chooseMode

public Mode chooseMode(Envir env)

Description copied from class: FlatPred

Choose the mode that this predicate could use in this environment. The result is null if no evaluation is possible. Otherwise, the resulting Mode object contains an updated environment (with any output variables added), plus various estimates about how expensive this predicate will be to execute.

Specified by:

chooseMode in class FlatPred

Returns:

The Mode object, with statistics and an updated environment.

startEvaluation

public void startEvaluation()

Overrides:

startEvaluation in class FlatPred

nextEvaluation

public boolean nextEvaluation()

Description copied from class: FlatPred

Generates the next solution that satisfies this predicate. This must only be called after startEvaluation().

Specified by:

nextEvaluation in class FlatPred

Returns:

true iff another solution has been found.

toString

public String toString()

Prints the FlatMember with optional bounds information.

Overrides:

toString in class FlatPred

accept

public <R> R accept(net.sourceforge.czt.util.Visitor<R> visitor)

Description copied from class: FlatPred

Calls visitor.visitPred (preferably) or visitor.visitTerm. Subclasses that correspond to particular kinds of Pred should override this to call more specific visitXXX methods (and should call super to handle the remaining cases).

Overrides:

accept in class FlatPred