MNASolverDirect.cpp

/* Copyright 2017-2021 Institute for Automation of Complex Power Systems,
 *                     EONERC, RWTH Aachen University
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 *********************************************************************************/
 
#include <dpsim/MNASolverDirect.h>
#include <dpsim/SequentialScheduler.h>
 
using namespace DPsim;
using namespace CPS;
 
namespace DPsim {
 
template <typename VarType>
MnaSolverDirect<VarType>::MnaSolverDirect(String name, CPS::Domain domain,
                                          CPS::Logger::Level logLevel)
    : MnaSolver<VarType>(name, domain, logLevel) {
  mImplementationInUse = DirectLinearSolverImpl::KLU;
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::switchedMatrixEmpty(std::size_t index) {
  mSwitchedMatrices[std::bitset<SWITCH_NUM>(index)][0].setZero();
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::switchedMatrixEmpty(std::size_t swIdx,
                                                   Int freqIdx) {
  mSwitchedMatrices[std::bitset<SWITCH_NUM>(swIdx)][freqIdx].setZero();
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::switchedMatrixStamp(
    std::size_t index, std::vector<std::shared_ptr<CPS::MNAInterface>> &comp) {
  auto bit = std::bitset<SWITCH_NUM>(index);
  auto &sys = mSwitchedMatrices[bit][0];
  for (auto component : comp) {
    component->mnaApplySystemMatrixStamp(sys);
  }
  for (UInt i = 0; i < mSwitches.size(); ++i)
    mSwitches[i]->mnaApplySwitchSystemMatrixStamp(bit[i], sys, 0);
 
  // Compute LU-factorization for system matrix
  mDirectLinearSolvers[bit][0]->preprocessing(sys,
                                              mListVariableSystemMatrixEntries);
  auto start = std::chrono::steady_clock::now();
  mDirectLinearSolvers[bit][0]->factorize(sys);
  auto end = std::chrono::steady_clock::now();
  std::chrono::duration<Real> diff = end - start;
  mFactorizeTimes.push_back(diff.count());
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::stampVariableSystemMatrix() {
 
  this->mDirectLinearSolverVariableSystemMatrix =
      createDirectSolverImplementation(mSLog);
  // TODO: a direct linear solver configuration is only applied if system matrix recomputation is used
  this->mDirectLinearSolverVariableSystemMatrix->setConfiguration(
      mConfigurationInUse);
 
  SPDLOG_LOGGER_INFO(mSLog,
                     "Number of variable Elements: {}"
                     "\nNumber of MNA components: {}",
                     mVariableComps.size(), mMNAComponents.size());
 
  // Build base matrix with only static elements
  mBaseSystemMatrix.setZero();
  for (auto statElem : mMNAComponents)
    statElem->mnaApplySystemMatrixStamp(mBaseSystemMatrix);
  SPDLOG_LOGGER_INFO(mSLog, "Base matrix with only static elements: {}",
                     Logger::matrixToString(mBaseSystemMatrix));
  mSLog->flush();
 
  // Continue from base matrix
  mVariableSystemMatrix = mBaseSystemMatrix;
 
  // Now stamp initial state of variable elements and switches into matrix
  SPDLOG_LOGGER_INFO(mSLog, "Stamping variable elements");
  for (auto varElem : mMNAIntfVariableComps)
    varElem->mnaApplySystemMatrixStamp(mVariableSystemMatrix);
 
  SPDLOG_LOGGER_INFO(mSLog, "Initial system matrix with variable elements {}",
                     Logger::matrixToString(mVariableSystemMatrix));
  /* TODO: find replacement for flush() */
  mSLog->flush();
 
  // Calculate factorization of current matrix
  mDirectLinearSolverVariableSystemMatrix->preprocessing(
      mVariableSystemMatrix, mListVariableSystemMatrixEntries);
 
  auto start = std::chrono::steady_clock::now();
  mDirectLinearSolverVariableSystemMatrix->factorize(mVariableSystemMatrix);
  auto end = std::chrono::steady_clock::now();
  std::chrono::duration<Real> diff = end - start;
  mFactorizeTimes.push_back(diff.count());
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::solveWithSystemMatrixRecomputation(
    Real time, Int timeStepCount) {
  // Reset source vector
  mRightSideVector.setZero();
 
  // Add together the right side vector (computed by the components'
  // pre-step tasks)
  for (auto stamp : mRightVectorStamps)
    mRightSideVector += *stamp;
 
  // Get switch and variable comp status and update system matrix and lu factorization accordingly
  mVariableComponentChanged = hasVariableComponentChanged();
  if (mVariableComponentChanged)
    recomputeSystemMatrix(time);
 
  // Calculate new solution vector
  auto start = std::chrono::steady_clock::now();
  **mLeftSideVector =
      mDirectLinearSolverVariableSystemMatrix->solve(mRightSideVector);
  auto end = std::chrono::steady_clock::now();
  std::chrono::duration<Real> diff = end - start;
  mSolveTimes.push_back(diff.count());
 
  // TODO split into separate task? (dependent on x, updating all v attributes)
  for (UInt nodeIdx = 0; nodeIdx < mNumNetNodes; ++nodeIdx)
    mNodes[nodeIdx]->mnaUpdateVoltage(**mLeftSideVector);
 
  // Components' states will be updated by the post-step tasks
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::recomputeSystemMatrix(Real time) {
  // Start from base matrix
  mVariableSystemMatrix = mBaseSystemMatrix;
 
  // Now stamp variable elements and switches into matrix
  for (auto comp : mMNAIntfVariableComps)
    comp->mnaApplySystemMatrixStamp(mVariableSystemMatrix);
 
  // Refactorization of matrix assuming that structure remained
  // constant by omitting analyzePattern
  auto start = std::chrono::steady_clock::now();
  mDirectLinearSolverVariableSystemMatrix->partialRefactorize(
      mVariableSystemMatrix, mListVariableSystemMatrixEntries);
  auto end = std::chrono::steady_clock::now();
  std::chrono::duration<Real> diff = end - start;
  mRecomputationTimes.push_back(diff.count());
  ++mNumRecomputations;
}
 
template <typename VarType> void MnaSolverDirect<VarType>::extractStateSpace() {
  if (!mStateSpaceExtractor)
    return;
 
  if (mSystemMatrixRecomputation) {
    mStateSpaceExtractor->extract(*mDirectLinearSolverVariableSystemMatrix,
                                  mVariableComponentChanged,
                                  mVariableComponentChanged);
  } else {
    mStateSpaceExtractor->extract(
        *mDirectLinearSolvers[mCurrentSwitchStatus][0], false,
        mSystemMatrixChanged);
  }
}
 
template <> void MnaSolverDirect<Real>::createEmptySystemMatrix() {
  if (mSwitches.size() > SWITCH_NUM)
    throw SystemError("Too many Switches.");
 
  if (mSystemMatrixRecomputation) {
    mBaseSystemMatrix =
        SparseMatrix(mNumMatrixNodeIndices, mNumMatrixNodeIndices);
    mVariableSystemMatrix =
        SparseMatrix(mNumMatrixNodeIndices, mNumMatrixNodeIndices);
  } else {
    for (std::size_t i = 0; i < (1ULL << mSwitches.size()); i++) {
      auto bit = std::bitset<SWITCH_NUM>(i);
      mSwitchedMatrices[bit].push_back(
          SparseMatrix(mNumMatrixNodeIndices, mNumMatrixNodeIndices));
      mDirectLinearSolvers[bit].push_back(
          createDirectSolverImplementation(mSLog));
    }
  }
}
 
template <> void MnaSolverDirect<Complex>::createEmptySystemMatrix() {
  if (mSwitches.size() > SWITCH_NUM)
    throw SystemError("Too many Switches.");
 
  if (mFrequencyParallel) {
    for (UInt i = 0; i < std::pow(2, mSwitches.size()); ++i) {
      for (Int freq = 0; freq < mSystem.mFrequencies.size(); ++freq) {
        auto bit = std::bitset<SWITCH_NUM>(i);
        mSwitchedMatrices[bit].push_back(SparseMatrix(
            2 * (mNumMatrixNodeIndices), 2 * (mNumMatrixNodeIndices)));
        mDirectLinearSolvers[bit].push_back(
            createDirectSolverImplementation(mSLog));
      }
    }
  } else if (mSystemMatrixRecomputation) {
    mBaseSystemMatrix =
        SparseMatrix(2 * (mNumMatrixNodeIndices), 2 * (mNumMatrixNodeIndices));
    mVariableSystemMatrix =
        SparseMatrix(2 * (mNumMatrixNodeIndices), 2 * (mNumMatrixNodeIndices));
  } else {
    for (std::size_t i = 0; i < (1ULL << mSwitches.size()); i++) {
      auto bit = std::bitset<SWITCH_NUM>(i);
      mSwitchedMatrices[bit].push_back(SparseMatrix(
          2 * (mNumTotalMatrixNodeIndices), 2 * (mNumTotalMatrixNodeIndices)));
      mDirectLinearSolvers[bit].push_back(
          createDirectSolverImplementation(mSLog));
    }
  }
}
 
template <typename VarType>
std::shared_ptr<CPS::Task> MnaSolverDirect<VarType>::createSolveTask() {
  return std::make_shared<MnaSolverDirect<VarType>::SolveTask>(*this);
}
 
template <typename VarType>
std::shared_ptr<CPS::Task> MnaSolverDirect<VarType>::createSolveTaskRecomp() {
  return std::make_shared<MnaSolverDirect<VarType>::SolveTaskRecomp>(*this);
}
 
template <typename VarType>
std::shared_ptr<CPS::Task>
MnaSolverDirect<VarType>::createSolveTaskHarm(UInt freqIdx) {
  return std::make_shared<MnaSolverDirect<VarType>::SolveTaskHarm>(*this,
                                                                   freqIdx);
}
 
template <typename VarType>
std::shared_ptr<CPS::Task>
MnaSolverDirect<VarType>::createStateSpaceExtractionTask() {
  return std::make_shared<
      typename MnaSolverDirect<VarType>::StateSpaceExtractionTask>(*this);
}
 
template <typename VarType>
std::shared_ptr<CPS::Task> MnaSolverDirect<VarType>::createLogTask() {
  return std::make_shared<MnaSolverDirect<VarType>::LogTask>(*this);
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::solve(Real time, Int timeStepCount) {
  const auto previousSwitchStatus = mCurrentSwitchStatus;
  // Reset source vector
  mRightSideVector.setZero();
 
  // Add together the right side vector (computed by the components' pre-step tasks)
  for (auto stamp : mRightVectorStamps)
    mRightSideVector += *stamp;
 
  if (!mIsInInitialization)
    MnaSolver<VarType>::updateSwitchStatus();
 
  if (mSwitchedMatrices.size() > 0) {
    std::chrono::steady_clock::time_point start;
    if (Solver::mLogSolveTimes)
      start = std::chrono::steady_clock::now();
 
    **mLeftSideVector =
        mDirectLinearSolvers[mCurrentSwitchStatus][0]->solve(mRightSideVector);
 
    if (Solver::mLogSolveTimes) {
      auto end = std::chrono::steady_clock::now();
      std::chrono::duration<Real> diff = end - start;
      mSolveTimes.push_back(diff.count());
    }
  }
 
  // CHECK: Is this really required? Or can operations actually become part of
  // correctorStep and mnaPostStep?
  for (auto syncGen : mSyncGen)
    syncGen->updateVoltage(**mLeftSideVector);
 
  // Reset number of iterations
  mIter = 0;
 
  // Additional solve steps for iterative models
  if (mSyncGen.size() > 0) {
    UInt numCompsRequireIter;
    do {
      // count synchronous generators that require iteration
      numCompsRequireIter = 0;
      for (auto syncGen : mSyncGen)
        if (syncGen->requiresIteration())
          numCompsRequireIter++;
 
      // recompute solve step if at least one component demands iteration
      if (numCompsRequireIter > 0) {
        mIter++;
 
        // Reset source vector
        mRightSideVector.setZero();
 
        if (!mIsInInitialization)
          MnaSolver<VarType>::updateSwitchStatus();
 
        for (auto syncGen : mSyncGen)
          syncGen->correctorStep();
 
        // Add together the right side vector (computed by the components' pre-step tasks)
        for (auto stamp : mRightVectorStamps)
          mRightSideVector += *stamp;
 
        if (mSwitchedMatrices.size() > 0) {
          auto start = std::chrono::steady_clock::now();
          **mLeftSideVector =
              mDirectLinearSolvers[mCurrentSwitchStatus][0]->solve(
                  mRightSideVector);
          auto end = std::chrono::steady_clock::now();
          std::chrono::duration<Real> diff = end - start;
          mSolveTimes.push_back(diff.count());
        }
 
        // CHECK: Is this really required? Or can operations actually become part of
        // correctorStep and mnaPostStep?
        for (auto syncGen : mSyncGen)
          syncGen->updateVoltage(**mLeftSideVector);
      }
    } while (numCompsRequireIter > 0);
  }
 
  mSystemMatrixChanged = (mCurrentSwitchStatus != previousSwitchStatus);
 
  // TODO split into separate task? (dependent on x, updating all v attributes)
  for (UInt nodeIdx = 0; nodeIdx < mNumNetNodes; ++nodeIdx)
    mNodes[nodeIdx]->mnaUpdateVoltage(**mLeftSideVector);
 
  // Components' states will be updated by the post-step tasks
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::solveWithHarmonics(Real time, Int timeStepCount,
                                                  Int freqIdx) {
  mRightSideVectorHarm[freqIdx].setZero();
 
  // Sum of right side vectors (computed by the components' pre-step tasks)
  for (auto stamp : mRightVectorStamps)
    mRightSideVectorHarm[freqIdx] += stamp->col(freqIdx);
 
  **mLeftSideVectorHarm[freqIdx] =
      mDirectLinearSolvers[mCurrentSwitchStatus][freqIdx]->solve(
          mRightSideVectorHarm[freqIdx]);
}
 
template <typename VarType> void MnaSolverDirect<VarType>::logSystemMatrices() {
  if (mFrequencyParallel) {
    for (UInt i = 0; i < mSwitchedMatrices[std::bitset<SWITCH_NUM>(0)].size();
         ++i) {
      SPDLOG_LOGGER_INFO(mSLog, "System matrix for frequency: {:d} \n{:s}", i,
                         Logger::matrixToString(
                             mSwitchedMatrices[std::bitset<SWITCH_NUM>(0)][i]));
    }
 
    for (UInt i = 0; i < mRightSideVectorHarm.size(); ++i) {
      SPDLOG_LOGGER_INFO(mSLog, "Right side vector for frequency: {:d} \n{:s}",
                         i, Logger::matrixToString(mRightSideVectorHarm[i]));
    }
 
  } else if (mSystemMatrixRecomputation) {
    SPDLOG_LOGGER_INFO(mSLog, "Summarizing matrices: ");
    SPDLOG_LOGGER_INFO(mSLog, "Base matrix with only static elements: {}",
                       Logger::matrixToString(mBaseSystemMatrix));
    SPDLOG_LOGGER_INFO(mSLog, "Initial system matrix with variable elements {}",
                       Logger::matrixToString(mVariableSystemMatrix));
    SPDLOG_LOGGER_INFO(mSLog, "Right side vector: {}",
                       Logger::matrixToString(mRightSideVector));
  } else {
    if (mSwitches.size() < 1) {
      SPDLOG_LOGGER_INFO(mSLog, "System matrix: \n{}",
                         mSwitchedMatrices[std::bitset<SWITCH_NUM>(0)][0]);
    } else {
      SPDLOG_LOGGER_INFO(mSLog, "Initial switch status: {:s}",
                         mCurrentSwitchStatus.to_string());
 
      for (auto sys : mSwitchedMatrices) {
        SPDLOG_LOGGER_INFO(mSLog, "Switching System matrix {:s} \n{:s}",
                           sys.first.to_string(),
                           Logger::matrixToString(sys.second[0]));
      }
    }
    SPDLOG_LOGGER_INFO(mSLog, "Right side vector: \n{}", mRightSideVector);
  }
}
 
template <typename VarType> void MnaSolverDirect<VarType>::logLUTimes() {
  logFactorizationTime();
  logRecomputationTime();
  logSolveTime();
}
 
template <typename VarType> void MnaSolverDirect<VarType>::logSolveTime() {
  Real solveSum = 0.0;
  Real solveMax = 0.0;
  for (auto meas : mSolveTimes) {
    solveSum += meas;
    if (meas > solveMax)
      solveMax = meas;
  }
  SPDLOG_LOGGER_INFO(mSLog, "Cumulative solve times: {:.12f}", solveSum);
  SPDLOG_LOGGER_INFO(mSLog, "Average solve time: {:.12f}",
                     solveSum / static_cast<double>(mSolveTimes.size()));
  SPDLOG_LOGGER_INFO(mSLog, "Maximum solve time: {:.12f}", solveMax);
  SPDLOG_LOGGER_INFO(mSLog, "Number of solves: {:d}", mSolveTimes.size());
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::logFactorizationTime() {
  for (auto meas : mFactorizeTimes) {
    SPDLOG_LOGGER_INFO(mSLog, "LU factorization time: {:.12f}", meas);
  }
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::logRecomputationTime() {
  Real recompSum = 0.0;
  Real recompMax = 0.0;
  for (auto meas : mRecomputationTimes) {
    recompSum += meas;
    if (meas > recompMax)
      recompMax = meas;
  }
  // Sometimes, refactorization is not used
  if (mRecomputationTimes.size() != 0) {
    SPDLOG_LOGGER_INFO(mSLog, "Cumulative refactorization times: {:.12f}",
                       recompSum);
    SPDLOG_LOGGER_INFO(mSLog, "Average refactorization time: {:.12f}",
                       recompSum / ((double)mRecomputationTimes.size()));
    SPDLOG_LOGGER_INFO(mSLog, "Maximum refactorization time: {:.12f}",
                       recompMax);
    SPDLOG_LOGGER_INFO(mSLog, "Number of refactorizations: {:d}",
                       mRecomputationTimes.size());
  }
}
 
template <typename VarType>
std::shared_ptr<DirectLinearSolver>
MnaSolverDirect<VarType>::createDirectSolverImplementation(
    CPS::Logger::Log mSLog) {
  switch (this->mImplementationInUse) {
  case DirectLinearSolverImpl::DenseLU:
    return std::make_shared<DenseLUAdapter>(mSLog);
  case DirectLinearSolverImpl::SparseLU:
    return std::make_shared<SparseLUAdapter>(mSLog);
#ifdef WITH_KLU
  case DirectLinearSolverImpl::KLU:
    return std::make_shared<KLUAdapter>(mSLog);
#endif
#ifdef WITH_CUDA
  case DirectLinearSolverImpl::CUDADense:
    return std::make_shared<GpuDenseAdapter>(mSLog);
#ifdef WITH_CUDA_SPARSE
  case DirectLinearSolverImpl::CUDASparse:
    return std::make_shared<GpuSparseAdapter>(mSLog);
#endif
#ifdef WITH_MAGMA
  case DirectLinearSolverImpl::CUDAMagma:
    return std::make_shared<GpuMagmaAdapter>(mSLog);
#endif
#endif
  default:
    throw CPS::SystemError("unsupported linear solver implementation.");
  }
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::setDirectLinearSolverImplementation(
    DirectLinearSolverImpl implementation) {
  this->mImplementationInUse = implementation;
}
 
template <typename VarType>
void MnaSolverDirect<VarType>::setDirectLinearSolverConfiguration(
    DirectLinearSolverConfiguration &configuration) {
  this->mConfigurationInUse = configuration;
}
 
} // namespace DPsim
 
template class DPsim::MnaSolverDirect<Real>;
template class DPsim::MnaSolverDirect<Complex>;