Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / QueryOperators / Inlined / LongAverageAggregationOperator.cs / 1305376 / LongAverageAggregationOperator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // LongAverageAggregationOperator.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined average aggregation operator and its enumerator, for longs. /// internal sealed class LongAverageAggregationOperator : InlinedAggregationOperator, double> { //---------------------------------------------------------------------------------------- // Constructs a new instance of an average associative operator. // internal LongAverageAggregationOperator(IEnumerable child) : base(child) { } //--------------------------------------------------------------------------------------- // Executes the entire query tree, and aggregates the intermediate results into the // final result based on the binary operators and final reduction. // // Return Value: // The single result of aggregation. // protected override double InternalAggregate(ref Exception singularExceptionToThrow) { // Because the final reduction is typically much cheaper than the intermediate // reductions over the individual partitions, and because each parallel partition // will do a lot of work to produce a single output element, we prefer to turn off // pipelining, and process the final reductions serially. using (IEnumerator > enumerator = GetEnumerator(ParallelMergeOptions.FullyBuffered, true)) { // Throw an error for empty results. if (!enumerator.MoveNext()) { singularExceptionToThrow = new InvalidOperationException(SR.GetString(SR.NoElements)); return default(double); } Pair result = enumerator.Current; // Simply add together the sums and totals. while (enumerator.MoveNext()) { checked { result.First += enumerator.Current.First; result.Second += enumerator.Current.Second; } } // And divide the sum by the total to obtain the final result. return (double)result.First / result.Second; } } //--------------------------------------------------------------------------------------- // Creates an enumerator that is used internally for the final aggregation step. // protected override QueryOperatorEnumerator , int> CreateEnumerator ( int index, int count, QueryOperatorEnumerator source, object sharedData, CancellationToken cancellationToken) { return new LongAverageAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class LongAverageAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator > { private QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal LongAverageAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Tallies up the average of the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref Pair currentElement) { // The temporary result contains the running sum and count, respectively. long sum = 0; long count = 0; QueryOperatorEnumerator source = m_source; long current = default(long); TKey keyUnused = default(TKey); if (source.MoveNext(ref current, ref keyUnused)) { int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); checked { sum += current; count++; } } while (source.MoveNext(ref current, ref keyUnused)); currentElement = new Pair (sum, count); return true; } return false; } //---------------------------------------------------------------------------------------- // Dispose of resources associated with the underlying enumerator. // protected override void Dispose(bool disposing) { Contract.Assert(m_source != null); m_source.Dispose(); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // LongAverageAggregationOperator.cs // // [....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined average aggregation operator and its enumerator, for longs. /// internal sealed class LongAverageAggregationOperator : InlinedAggregationOperator, double> { //---------------------------------------------------------------------------------------- // Constructs a new instance of an average associative operator. // internal LongAverageAggregationOperator(IEnumerable child) : base(child) { } //--------------------------------------------------------------------------------------- // Executes the entire query tree, and aggregates the intermediate results into the // final result based on the binary operators and final reduction. // // Return Value: // The single result of aggregation. // protected override double InternalAggregate(ref Exception singularExceptionToThrow) { // Because the final reduction is typically much cheaper than the intermediate // reductions over the individual partitions, and because each parallel partition // will do a lot of work to produce a single output element, we prefer to turn off // pipelining, and process the final reductions serially. using (IEnumerator > enumerator = GetEnumerator(ParallelMergeOptions.FullyBuffered, true)) { // Throw an error for empty results. if (!enumerator.MoveNext()) { singularExceptionToThrow = new InvalidOperationException(SR.GetString(SR.NoElements)); return default(double); } Pair result = enumerator.Current; // Simply add together the sums and totals. while (enumerator.MoveNext()) { checked { result.First += enumerator.Current.First; result.Second += enumerator.Current.Second; } } // And divide the sum by the total to obtain the final result. return (double)result.First / result.Second; } } //--------------------------------------------------------------------------------------- // Creates an enumerator that is used internally for the final aggregation step. // protected override QueryOperatorEnumerator , int> CreateEnumerator ( int index, int count, QueryOperatorEnumerator source, object sharedData, CancellationToken cancellationToken) { return new LongAverageAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class LongAverageAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator > { private QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal LongAverageAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Tallies up the average of the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref Pair currentElement) { // The temporary result contains the running sum and count, respectively. long sum = 0; long count = 0; QueryOperatorEnumerator source = m_source; long current = default(long); TKey keyUnused = default(TKey); if (source.MoveNext(ref current, ref keyUnused)) { int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); checked { sum += current; count++; } } while (source.MoveNext(ref current, ref keyUnused)); currentElement = new Pair (sum, count); return true; } return false; } //---------------------------------------------------------------------------------------- // Dispose of resources associated with the underlying enumerator. // protected override void Dispose(bool disposing) { Contract.Assert(m_source != null); m_source.Dispose(); } } } } // 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
- RemoteWebConfigurationHost.cs
- CompositeScriptReference.cs
- TabItemWrapperAutomationPeer.cs
- Int32.cs
- RadioButtonPopupAdapter.cs
- QuaternionRotation3D.cs
- SkipQueryOptionExpression.cs
- BitmapEffectGroup.cs
- Axis.cs
- ScriptHandlerFactory.cs
- BindingsCollection.cs
- CheckBox.cs
- RowToFieldTransformer.cs
- QuestionEventArgs.cs
- DataRelationCollection.cs
- StateRuntime.cs
- EventWaitHandleSecurity.cs
- TextServicesProperty.cs
- ControlUtil.cs
- CSharpCodeProvider.cs
- GenericEnumerator.cs
- CommandLibraryHelper.cs
- WebMessageEncodingBindingElement.cs
- ZipIOLocalFileBlock.cs
- DispatcherTimer.cs
- DriveNotFoundException.cs
- Storyboard.cs
- ColorInterpolationModeValidation.cs
- CapabilitiesRule.cs
- AutoGeneratedField.cs
- PackWebRequest.cs
- RadioButtonStandardAdapter.cs
- WebAdminConfigurationHelper.cs
- Matrix3D.cs
- UnsafeNativeMethods.cs
- XmlCustomFormatter.cs
- FontUnit.cs
- BatchWriter.cs
- BindingNavigator.cs
- DrawingBrush.cs
- TypeBuilder.cs
- HTTPRemotingHandler.cs
- DataControlCommands.cs
- DependencySource.cs
- SqlInternalConnectionSmi.cs
- MultipartIdentifier.cs
- SystemIPAddressInformation.cs
- ItemContainerPattern.cs
- AffineTransform3D.cs
- XhtmlBasicSelectionListAdapter.cs
- UnSafeCharBuffer.cs
- Error.cs
- CodeCommentStatement.cs
- ServerIdentity.cs
- Menu.cs
- ModelTreeEnumerator.cs
- BinaryCommonClasses.cs
- HttpFileCollectionBase.cs
- Permission.cs
- InfoCardServiceInstallComponent.cs
- CultureInfoConverter.cs
- ListView.cs
- ScopelessEnumAttribute.cs
- GridViewCancelEditEventArgs.cs
- DataBindingCollection.cs
- TreeBuilderXamlTranslator.cs
- ObjectHandle.cs
- ChangeTracker.cs
- TextEffectCollection.cs
- ListManagerBindingsCollection.cs
- NetworkInformationException.cs
- Authorization.cs
- RelatedPropertyManager.cs
- QilInvokeLateBound.cs
- WindowsNonControl.cs
- XmlSchemaDatatype.cs
- RectangleGeometry.cs
- NullableBoolConverter.cs
- DirectoryInfo.cs
- PermissionAttributes.cs
- PageSetupDialog.cs
- LocatorGroup.cs
- AvtEvent.cs
- WeakEventManager.cs
- ResourceDescriptionAttribute.cs
- UpdateProgress.cs
- XmlWhitespace.cs
- MimeBasePart.cs
- CircleHotSpot.cs
- SoapAttributes.cs
- DeploymentExceptionMapper.cs
- Inline.cs
- EncoderFallback.cs
- InsufficientMemoryException.cs
- EntityStoreSchemaGenerator.cs
- XmlBinaryReader.cs
- XamlFxTrace.cs
- SystemThemeKey.cs
- SizeAnimationClockResource.cs
- PrimitiveSchema.cs