From 0fb4faeffa6fb6461361383ba257f21c7fae71c9 Mon Sep 17 00:00:00 2001
From: Christoph Rettinger <christoph.rettinger@fau.de>
Date: Thu, 14 Jun 2018 17:42:24 +0200
Subject: [PATCH] Changed implementation of subcycling to avoid unnecessary
synchronizations
---
src/pe_coupling/utility/TimeStep.h | 64 +++++++++++++-----------------
1 file changed, 27 insertions(+), 37 deletions(-)
diff --git a/src/pe_coupling/utility/TimeStep.h b/src/pe_coupling/utility/TimeStep.h
index d89e0a6e7..f32c30614 100644
--- a/src/pe_coupling/utility/TimeStep.h
+++ b/src/pe_coupling/utility/TimeStep.h
@@ -35,7 +35,7 @@
#include <functional>
#include <map>
-
+#include <array>
namespace walberla {
namespace pe_coupling {
@@ -88,43 +88,25 @@ public:
// Since they are reset after the call to collision response, they have to be stored explicitly before.
// Then they are set again after each intermediate step.
- // sum up all forces/torques from shadow copies on local body (owner)
- pe::reduceForces( blockStorage_->getBlockStorage(), bodyStorageID_ );
- // send total forces/torques to shadow owners
- pe::distributeForces( blockStorage_->getBlockStorage(), bodyStorageID_ );
-
// generate map from all known bodies (process local) to total forces/torques
- std::map< walberla::id_t, std::vector< real_t > > forceMap;
+ // this has to be done on a block-local basis, since the same body could reside on several blocks from this process
+ typedef domain_decomposition::IBlockID::IDType BlockID_T;
+ std::map< BlockID_T, std::map< walberla::id_t, std::array< real_t, 6 > > > forceTorqueMap;
+
for( auto blockIt = blockStorage_->begin(); blockIt != blockStorage_->end(); ++blockIt )
{
+ BlockID_T blockID = blockIt->getId().getID();
+ auto& blockLocalForceTorqueMap = forceTorqueMap[blockID];
+
// iterate over local and remote bodies and store force/torque in map
- // Remote bodies are required since during the then following collision response time steps,
- // bodies can change ownership (i.e. a now remote body could become a local body ).
- // Since only the owning process re-sets the force/torque later, remote body values have to be stored as well.
for( auto bodyIt = pe::BodyIterator::begin(*blockIt, bodyStorageID_); bodyIt != pe::BodyIterator::end(); ++bodyIt )
{
- auto & f = forceMap[ bodyIt->getSystemID() ];
+ auto & f = blockLocalForceTorqueMap[ bodyIt->getSystemID() ];
- // only add if body has not been added already before (from another block)
- if( f.empty() )
- {
- const auto & force = bodyIt->getForce();
- f.push_back( force[0] );
- f.push_back( force[1] );
- f.push_back( force[2] );
-
- const auto & torque = bodyIt->getTorque();
- f.push_back( torque[0] );
- f.push_back( torque[1] );
- f.push_back( torque[2] );
- }
+ const auto & force = bodyIt->getForce();
+ const auto & torque = bodyIt->getTorque();
- // reset of force/torque on remote bodies necessary to erase the multiple occurrences of forces/torques on bodies
- // (due to call to distributeForces() before)
- if ( bodyIt->isRemote() )
- {
- bodyIt->resetForceAndTorque();
- }
+ f = {{force[0], force[1], force[2], torque[0], torque[1], torque[2] }};
}
}
@@ -133,18 +115,26 @@ public:
for( uint_t i = 0; i != numberOfSubIterations_; ++i )
{
- // in the first iteration, forces on local bodies are already set by force synchronization
+ // in the first iteration, forces are already set
if( i != 0 )
{
for( auto blockIt = blockStorage_->begin(); blockIt != blockStorage_->end(); ++blockIt )
{
- // only owning process sets force/torque on bodies
- for( auto bodyIt = pe::LocalBodyIterator::begin(*blockIt, bodyStorageID_); bodyIt != pe::LocalBodyIterator::end(); ++bodyIt )
+ BlockID_T blockID = blockIt->getId().getID();
+ auto& blockLocalForceTorqueMap = forceTorqueMap[blockID];
+
+ // re-set stored force/torque on bodies
+ for( auto bodyIt = pe::BodyIterator::begin(*blockIt, bodyStorageID_); bodyIt != pe::BodyIterator::end(); ++bodyIt )
{
- const auto & f = forceMap[ bodyIt->getSystemID() ];
- WALBERLA_ASSERT( !f.empty(), "When attempting to set force/torque on local body " << bodyIt->getSystemID() << " at position " << bodyIt->getPosition() << ", body was not found in map!");
- bodyIt->addForce ( f[0], f[1], f[2] );
- bodyIt->addTorque( f[3], f[4], f[5] );
+
+ const auto f = blockLocalForceTorqueMap.find( bodyIt->getSystemID() );
+
+ if( f != blockLocalForceTorqueMap.end() )
+ {
+ const auto & ftValues = f->second;
+ bodyIt->addForce ( ftValues[0], ftValues[1], ftValues[2] );
+ bodyIt->addTorque( ftValues[3], ftValues[4], ftValues[5] );
+ }
}
}
}
--
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