Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / QueryOperators / Inlined / FloatSumAggregationOperator.cs / 1305376 / FloatSumAggregationOperator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // FloatSumAggregationOperator.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined sum aggregation and its enumerator, for floats. /// internal sealed class FloatSumAggregationOperator : InlinedAggregationOperator{ //---------------------------------------------------------------------------------------- // Constructs a new instance of a sum associative operator. // internal FloatSumAggregationOperator(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 float 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)) { // We just reduce the elements in each output partition. double sum = 0.0; while (enumerator.MoveNext()) { checked { sum += enumerator.Current; } } return (float)sum; } } //--------------------------------------------------------------------------------------- // Creates an enumerator that is used internally for the final aggregation step. // protected override QueryOperatorEnumerator CreateEnumerator ( int index, int count, QueryOperatorEnumerator source, object sharedData, CancellationToken cancellationToken) { return new FloatSumAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class FloatSumAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal FloatSumAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Tallies up the sum of the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref double currentElement) { float element = default(float); TKey keyUnused = default(TKey); QueryOperatorEnumerator source = m_source; if (source.MoveNext(ref element, ref keyUnused)) { // We just scroll through the enumerator and accumulate the sum. double tempSum = 0.0f; int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); tempSum += element; } while (source.MoveNext(ref element, ref keyUnused)); // The sum has been calculated. Now just return. currentElement = tempSum; 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
- MsmqPoisonMessageException.cs
- basenumberconverter.cs
- SqlVersion.cs
- SqlCachedBuffer.cs
- TextLineBreak.cs
- ParserStreamGeometryContext.cs
- ExtensionDataReader.cs
- Resources.Designer.cs
- ChannelServices.cs
- CompoundFileIOPermission.cs
- TargetParameterCountException.cs
- Baml2006ReaderFrame.cs
- CryptoApi.cs
- XmlKeywords.cs
- ColorConvertedBitmapExtension.cs
- CoTaskMemHandle.cs
- Base64Stream.cs
- IItemProperties.cs
- ChannelManager.cs
- PointConverter.cs
- SelectedCellsChangedEventArgs.cs
- WindowsNonControl.cs
- CodeThrowExceptionStatement.cs
- DateTimePicker.cs
- XmlRawWriterWrapper.cs
- SQLInt16Storage.cs
- AffineTransform3D.cs
- WebPartCatalogCloseVerb.cs
- ProfileBuildProvider.cs
- VersionedStream.cs
- PropertyGrid.cs
- EntityClassGenerator.cs
- SqlMetaData.cs
- StsCommunicationException.cs
- FrameworkContentElement.cs
- RootBuilder.cs
- ExpressionEditorAttribute.cs
- RequestNavigateEventArgs.cs
- OleDbEnumerator.cs
- ClassData.cs
- ImageField.cs
- InvalidFilterCriteriaException.cs
- ListChangedEventArgs.cs
- HMACSHA512.cs
- DesigntimeLicenseContextSerializer.cs
- InputLanguage.cs
- LayoutManager.cs
- InlineUIContainer.cs
- CompiledQuery.cs
- InvalidDocumentContentsException.cs
- StateWorkerRequest.cs
- PreProcessInputEventArgs.cs
- _BufferOffsetSize.cs
- ToolTipService.cs
- HMACMD5.cs
- Validator.cs
- WebBrowserEvent.cs
- SynchronizedDispatch.cs
- PathFigureCollection.cs
- Cloud.cs
- TrustSection.cs
- PrincipalPermission.cs
- SqlDependencyListener.cs
- DataKeyCollection.cs
- EventLogPermissionEntry.cs
- InputScopeNameConverter.cs
- DefaultParameterValueAttribute.cs
- AttributeData.cs
- CurrentChangingEventArgs.cs
- PropertyValueEditor.cs
- XsltContext.cs
- MimeMultiPart.cs
- BrowserDefinitionCollection.cs
- NavigatingCancelEventArgs.cs
- PrintPageEvent.cs
- DataGridViewRowDividerDoubleClickEventArgs.cs
- XmlILConstructAnalyzer.cs
- XmlReader.cs
- AsyncDataRequest.cs
- VisualBrush.cs
- PersonalizationDictionary.cs
- UriExt.cs
- ReflectionUtil.cs
- MessageSecurityException.cs
- SystemWebCachingSectionGroup.cs
- ExternalCalls.cs
- AttributeQuery.cs
- ActivityBuilderHelper.cs
- SerializationException.cs
- AttributeEmitter.cs
- DataGridViewRowsAddedEventArgs.cs
- QilXmlWriter.cs
- SynchronousReceiveElement.cs
- Label.cs
- DocumentOutline.cs
- XmlValidatingReader.cs
- HtmlShim.cs
- DurableInstance.cs
- SspiHelper.cs
- _DigestClient.cs