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/*=========================================================================
*
* Copyright NumFOCUS
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#ifndef itkDomainThreader_hxx
#define itkDomainThreader_hxx
namespace itk
{
template <typename TDomainPartitioner, typename TAssociate>
DomainThreader<TDomainPartitioner, TAssociate>::DomainThreader()
: m_Associate(nullptr)
{
this->m_DomainPartitioner = DomainPartitionerType::New();
this->m_MultiThreader = MultiThreaderBase::New();
this->m_NumberOfWorkUnits = this->m_MultiThreader->GetNumberOfWorkUnits();
}
template <typename TDomainPartitioner, typename TAssociate>
MultiThreaderBase *
DomainThreader<TDomainPartitioner, TAssociate>::GetMultiThreader() const
{
return this->m_MultiThreader;
}
template <typename TDomainPartitioner, typename TAssociate>
void
DomainThreader<TDomainPartitioner, TAssociate>::SetMaximumNumberOfThreads(const ThreadIdType threads)
{
if (threads != this->GetMaximumNumberOfThreads())
{
this->m_MultiThreader->SetMaximumNumberOfThreads(threads);
this->Modified();
}
}
template <typename TDomainPartitioner, typename TAssociate>
void
DomainThreader<TDomainPartitioner, TAssociate>::Execute(TAssociate * enclosingClass, const DomainType & completeDomain)
{
this->m_Associate = enclosingClass;
this->m_CompleteDomain = completeDomain;
this->DetermineNumberOfWorkUnitsUsed();
this->BeforeThreadedExecution();
// This calls ThreadedExecution in each thread.
this->StartThreadingSequence();
this->AfterThreadedExecution();
}
template <typename TDomainPartitioner, typename TAssociate>
void
DomainThreader<TDomainPartitioner, TAssociate>::DetermineNumberOfWorkUnitsUsed()
{
ThreadIdType numberOfWorkUnits = this->GetNumberOfWorkUnits();
// Attempt a single dummy partition, just to get the number of subdomains actually created
DomainType subdomain;
this->m_NumberOfWorkUnitsUsed =
this->m_DomainPartitioner->PartitionDomain(0, numberOfWorkUnits, this->m_CompleteDomain, subdomain);
this->GetMultiThreader()->SetNumberOfWorkUnits(this->m_NumberOfWorkUnitsUsed);
if (this->m_NumberOfWorkUnitsUsed > numberOfWorkUnits)
{
itkExceptionMacro(
"A subclass of ThreadedDomainPartitioner::PartitionDomain returned more subdomains than were requested");
}
}
template <typename TDomainPartitioner, typename TAssociate>
void
DomainThreader<TDomainPartitioner, TAssociate>::StartThreadingSequence()
{
// Set up the multithreaded processing
ThreadStruct str;
str.domainThreader = this;
this->GetMultiThreader()->SetSingleMethodAndExecute(this->ThreaderCallback, &str);
}
template <typename TDomainPartitioner, typename TAssociate>
ITK_THREAD_RETURN_FUNCTION_CALL_CONVENTION
DomainThreader<TDomainPartitioner, TAssociate>::ThreaderCallback(void * arg)
{
auto * info = static_cast<MultiThreaderBase::WorkUnitInfo *>(arg);
auto * str = static_cast<ThreadStruct *>(info->UserData);
DomainThreader * thisDomainThreader = str->domainThreader;
const ThreadIdType workUnitID = info->WorkUnitID;
const ThreadIdType workUnitCount = info->NumberOfWorkUnits;
// Get the sub-domain to process for this thread.
DomainType subdomain;
const ThreadIdType total = thisDomainThreader->GetDomainPartitioner()->PartitionDomain(
workUnitID, workUnitCount, thisDomainThreader->m_CompleteDomain, subdomain);
// Execute the actual method with appropriate sub-domain.
// If the work unit ID is greater than the total number of regions
// that PartitionDomain will create, don't use this thread.
// Sometimes the threads don't break up very well and it is just
// as efficient to leave a few threads idle.
if (workUnitID < total)
{
thisDomainThreader->ThreadedExecution(subdomain, workUnitID);
}
return ITK_THREAD_RETURN_DEFAULT_VALUE;
}
} // namespace itk
#endif
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