Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Common / Utils / Boolean / Converter.cs / 1305376 / Converter.cs
//---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] // @backupOwner [....] //--------------------------------------------------------------------- using System; using System.Collections.Generic; using System.Text; using System.Diagnostics; using System.Collections.ObjectModel; using System.Globalization; using System.Linq; namespace System.Data.Common.Utils.Boolean { ////// Handles conversion of expressions to different forms (decision diagram, etc) /// internal sealed class Converter{ private readonly Vertex _vertex; private readonly ConversionContext _context; private DnfSentence _dnf; private CnfSentence _cnf; internal Converter(BoolExpr expr, ConversionContext context) { _context = context ?? IdentifierService .Instance.CreateConversionContext(); _vertex = ToDecisionDiagramConverter .TranslateToRobdd(expr, _context); } internal Vertex Vertex { get { return _vertex; } } internal DnfSentence Dnf { get { InitializeNormalForms(); return _dnf; } } internal CnfSentence Cnf { get { InitializeNormalForms(); return _cnf; } } /// /// Converts the decision diagram (Vertex) wrapped by this converter and translates it into DNF /// and CNF forms. I'll first explain the strategy with respect to DNF, and then explain how CNF /// is achieved in parallel. A DNF sentence representing the expression is simply a disjunction /// of every rooted path through the decision diagram ending in one. For instance, given the /// following decision diagram: /// /// A /// 0/ \1 /// B C /// 0/ \1 0/ \1 /// One Zero One /// /// the following paths evaluate to 'One' /// /// !A, !B /// A, C /// /// and the corresponding DNF is (!A.!B) + (A.C) /// /// It is easy to compute CNF from the DNF of the negation, e.g.: /// /// !((A.B) + (C.D)) iff. (!A+!B) . (!C+!D) /// /// To compute the CNF form in parallel, we negate the expression (by swapping One and Zero sinks) /// and collect negation of the literals along the path. In the above example, the following paths /// evaluate to 'Zero': /// /// !A, B /// A, !C /// /// and the CNF (which takes the negation of all literals in the path) is (!A+B) . (A+!C) /// private void InitializeNormalForms() { if (null == _cnf) { // short-circuit if the root is true/false if (_vertex.IsOne()) { // And() -> True _cnf = new CnfSentence(Set >.Empty); // Or(And()) -> True var emptyClause = new DnfClause (Set >.Empty); var emptyClauseSet = new Set >(); emptyClauseSet.Add(emptyClause); _dnf = new DnfSentence (emptyClauseSet.MakeReadOnly()); } else if (_vertex.IsZero()) { // And(Or()) -> False var emptyClause = new CnfClause (Set >.Empty); var emptyClauseSet = new Set >(); emptyClauseSet.Add(emptyClause); _cnf = new CnfSentence (emptyClauseSet.MakeReadOnly()); // Or() -> False _dnf = new DnfSentence (Set >.Empty); } else { // construct clauses by walking the tree and constructing a clause for each sink Set > dnfClauses = new Set >(); Set > cnfClauses = new Set >(); Set > path = new Set >(); FindAllPaths(_vertex, cnfClauses, dnfClauses, path); _cnf = new CnfSentence (cnfClauses.MakeReadOnly()); _dnf = new DnfSentence (dnfClauses.MakeReadOnly()); } } } private void FindAllPaths(Vertex vertex, Set > cnfClauses, Set > dnfClauses, Set > path) { if (vertex.IsOne()) { // create DNF clause var clause = new DnfClause (path); dnfClauses.Add(clause); } else if (vertex.IsZero()) { // create CNF clause var clause = new CnfClause (new Set >(path.Select(l => l.MakeNegated()))); cnfClauses.Add(clause); } else { // keep on walking... foreach (var successor in _context.GetSuccessors(vertex)) { path.Add(successor.Literal); FindAllPaths(successor.Vertex, cnfClauses, dnfClauses, path); path.Remove(successor.Literal); } } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. //---------------------------------------------------------------------- // // Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] // @backupOwner [....] //--------------------------------------------------------------------- using System; using System.Collections.Generic; using System.Text; using System.Diagnostics; using System.Collections.ObjectModel; using System.Globalization; using System.Linq; namespace System.Data.Common.Utils.Boolean { ////// Handles conversion of expressions to different forms (decision diagram, etc) /// internal sealed class Converter{ private readonly Vertex _vertex; private readonly ConversionContext _context; private DnfSentence _dnf; private CnfSentence _cnf; internal Converter(BoolExpr expr, ConversionContext context) { _context = context ?? IdentifierService .Instance.CreateConversionContext(); _vertex = ToDecisionDiagramConverter .TranslateToRobdd(expr, _context); } internal Vertex Vertex { get { return _vertex; } } internal DnfSentence Dnf { get { InitializeNormalForms(); return _dnf; } } internal CnfSentence Cnf { get { InitializeNormalForms(); return _cnf; } } /// /// Converts the decision diagram (Vertex) wrapped by this converter and translates it into DNF /// and CNF forms. I'll first explain the strategy with respect to DNF, and then explain how CNF /// is achieved in parallel. A DNF sentence representing the expression is simply a disjunction /// of every rooted path through the decision diagram ending in one. For instance, given the /// following decision diagram: /// /// A /// 0/ \1 /// B C /// 0/ \1 0/ \1 /// One Zero One /// /// the following paths evaluate to 'One' /// /// !A, !B /// A, C /// /// and the corresponding DNF is (!A.!B) + (A.C) /// /// It is easy to compute CNF from the DNF of the negation, e.g.: /// /// !((A.B) + (C.D)) iff. (!A+!B) . (!C+!D) /// /// To compute the CNF form in parallel, we negate the expression (by swapping One and Zero sinks) /// and collect negation of the literals along the path. In the above example, the following paths /// evaluate to 'Zero': /// /// !A, B /// A, !C /// /// and the CNF (which takes the negation of all literals in the path) is (!A+B) . (A+!C) /// private void InitializeNormalForms() { if (null == _cnf) { // short-circuit if the root is true/false if (_vertex.IsOne()) { // And() -> True _cnf = new CnfSentence(Set >.Empty); // Or(And()) -> True var emptyClause = new DnfClause (Set >.Empty); var emptyClauseSet = new Set >(); emptyClauseSet.Add(emptyClause); _dnf = new DnfSentence (emptyClauseSet.MakeReadOnly()); } else if (_vertex.IsZero()) { // And(Or()) -> False var emptyClause = new CnfClause (Set >.Empty); var emptyClauseSet = new Set >(); emptyClauseSet.Add(emptyClause); _cnf = new CnfSentence (emptyClauseSet.MakeReadOnly()); // Or() -> False _dnf = new DnfSentence (Set >.Empty); } else { // construct clauses by walking the tree and constructing a clause for each sink Set > dnfClauses = new Set >(); Set > cnfClauses = new Set >(); Set > path = new Set >(); FindAllPaths(_vertex, cnfClauses, dnfClauses, path); _cnf = new CnfSentence (cnfClauses.MakeReadOnly()); _dnf = new DnfSentence (dnfClauses.MakeReadOnly()); } } } private void FindAllPaths(Vertex vertex, Set > cnfClauses, Set > dnfClauses, Set > path) { if (vertex.IsOne()) { // create DNF clause var clause = new DnfClause (path); dnfClauses.Add(clause); } else if (vertex.IsZero()) { // create CNF clause var clause = new CnfClause (new Set >(path.Select(l => l.MakeNegated()))); cnfClauses.Add(clause); } else { // keep on walking... foreach (var successor in _context.GetSuccessors(vertex)) { path.Add(successor.Literal); FindAllPaths(successor.Vertex, cnfClauses, dnfClauses, path); path.Remove(successor.Literal); } } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu

This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- ElementHostPropertyMap.cs
- LifetimeServices.cs
- OperationGenerator.cs
- QueryExpr.cs
- SuppressMessageAttribute.cs
- SafePEFileHandle.cs
- ClientBuildManagerCallback.cs
- HelpEvent.cs
- ProcessModelInfo.cs
- ContextTokenTypeConverter.cs
- SubpageParaClient.cs
- SafeSecurityHandles.cs
- StrokeRenderer.cs
- DeferredBinaryDeserializerExtension.cs
- ConversionContext.cs
- PixelFormat.cs
- CodeStatement.cs
- StructuredTypeEmitter.cs
- ManagedFilter.cs
- DecodeHelper.cs
- RepeatInfo.cs
- _UncName.cs
- DataGridViewComponentPropertyGridSite.cs
- DataServiceClientException.cs
- StreamInfo.cs
- ChangePassword.cs
- SafeLibraryHandle.cs
- HttpFileCollection.cs
- SqlClientWrapperSmiStream.cs
- JournalEntryListConverter.cs
- ServiceParser.cs
- CollectionType.cs
- Geometry.cs
- SafeHandle.cs
- ExtentCqlBlock.cs
- GraphicsPath.cs
- Subset.cs
- UrlPath.cs
- TextChangedEventArgs.cs
- dataobject.cs
- SmiMetaData.cs
- Style.cs
- DBSchemaRow.cs
- ConfigurationHelpers.cs
- BufferedGraphicsContext.cs
- BaseValidator.cs
- UnionCqlBlock.cs
- ColumnBinding.cs
- DataGridViewRowPostPaintEventArgs.cs
- XmlLanguageConverter.cs
- LOSFormatter.cs
- SingleConverter.cs
- DefaultSection.cs
- RowType.cs
- BaseProcessor.cs
- HTMLTextWriter.cs
- SizeKeyFrameCollection.cs
- XmlQueryRuntime.cs
- FactoryGenerator.cs
- HttpChannelHelper.cs
- ExecutionEngineException.cs
- CacheChildrenQuery.cs
- CommonDialog.cs
- MouseButtonEventArgs.cs
- XmlSchemaAll.cs
- WindowsBrush.cs
- TypeProvider.cs
- DataSourceViewSchemaConverter.cs
- RequestQueryProcessor.cs
- GenericEnumerator.cs
- HtmlShim.cs
- SafeFileHandle.cs
- Rotation3D.cs
- Point3DKeyFrameCollection.cs
- BitmapEffectCollection.cs
- StateChangeEvent.cs
- XmlBuffer.cs
- IndentTextWriter.cs
- TypeUsage.cs
- ManipulationLogic.cs
- FastEncoderWindow.cs
- TagPrefixInfo.cs
- SizeConverter.cs
- WorkflowRuntimeServiceElementCollection.cs
- DbUpdateCommandTree.cs
- CustomAssemblyResolver.cs
- StartUpEventArgs.cs
- XmlSchemaAttributeGroupRef.cs
- WindowsSolidBrush.cs
- TypeConstant.cs
- DispatcherTimer.cs
- StaticFileHandler.cs
- StringFreezingAttribute.cs
- XmlText.cs
- RenamedEventArgs.cs
- ScrollableControl.cs
- Dictionary.cs
- Clipboard.cs
- UserNameSecurityTokenProvider.cs
- WindowsTab.cs