#include <FieldIOHdf5.h>

Inheritance diagram for Nektar::LibUtilities::FieldIOHdf5:

Classes
struct	OffsetHelper

Public Member Functions
	FieldIOHdf5 (LibUtilities::CommSharedPtr pComm, bool sharedFilesystem)
	Construct the FieldIO object for HDF5 output. More...

	~FieldIOHdf5 () override

Public Member Functions inherited from Nektar::LibUtilities::FieldIO
	FieldIO (LibUtilities::CommSharedPtr pComm, bool sharedFilesystem)
	Constructor for FieldIO base class. More...

virtual	~FieldIO ()

void	Write (const std::string &outFile, std::vector< FieldDefinitionsSharedPtr > &fielddefs, std::vector< std::vector< NekDouble > > &fielddata, const FieldMetaDataMap &fieldinfomap=NullFieldMetaDataMap, const bool backup=false)
	Write out the field information to the file `outFile`. More...

void	Import (const std::string &infilename, std::vector< FieldDefinitionsSharedPtr > &fielddefs, std::vector< std::vector< NekDouble > > &fielddata=NullVectorNekDoubleVector, FieldMetaDataMap &fieldinfomap=NullFieldMetaDataMap, const Array< OneD, int > &ElementIDs=NullInt1DArray)
	Read field information from the file `infilename`. More...

DataSourceSharedPtr	ImportFieldMetaData (const std::string &filename, FieldMetaDataMap &fieldmetadatamap)
	Import the metadata from a field file. More...

const std::string &	GetClassName () const

std::string	GetFileEnding () const
	Helper function that determines default file extension. More...

Static Public Member Functions
static FieldIOSharedPtr	create (LibUtilities::CommSharedPtr pComm, bool sharedFilesystem)
	Creates an instance of this class. More...

Static Public Member Functions inherited from Nektar::LibUtilities::FieldIO
static const std::string	GetFileType (const std::string &filename, CommSharedPtr comm)
	Determine file type of given input file. More...

static std::shared_ptr< FieldIO >	CreateDefault (const LibUtilities::SessionReaderSharedPtr session)
	Returns an object for the default FieldIO method. More...

static std::shared_ptr< FieldIO >	CreateForFile (const LibUtilities::SessionReaderSharedPtr session, const std::string &filename)
	Construct a FieldIO object for a given input filename. More...

static void	AddInfoTag (TagWriterSharedPtr root, const FieldMetaDataMap &fieldmetadatamap)
	Add provenance information to the field metadata map. More...

Static Public Attributes
static const unsigned int	FORMAT_VERSION = 1
	Version of the Nektar++ HDF5 format, which is embedded into the main NEKTAR group as an attribute. More...

static const unsigned int	ELEM_DCMP_IDX = 0
	A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of elements in decomposition (i.e. field definition). More...

static const unsigned int	VAL_DCMP_IDX = 1
	A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of data points in decomposition (i.e. field definition). More...

static const unsigned int	ORDER_DCMP_IDX = 2
	A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of elements multiplied by the dimension of the element, giving number of modes when variable polynomial order is defined. More...

static const unsigned int	HOMY_DCMP_IDX = 3
	A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of the number of y-planes for homogeneous simulations. More...

static const unsigned int	HOMZ_DCMP_IDX = 4
	A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of the number of z-planes for homogeneous simulations. More...

static const unsigned int	HOMS_DCMP_IDX = 5
	A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of the number of strips for homogeneous simulations. More...

static const unsigned int	HASH_DCMP_IDX = 6
	The hash of the field definition information, which defines the name of the attribute containing the field definition itself. More...

static const unsigned int	MAX_DCMPS = FieldIOHdf5::HASH_DCMP_IDX + 1
	A helper for FieldIOHdf5::v_Write. Describes the maximum number of items in the decomposition per field definition. More...

static const unsigned int	ELEM_CNT_IDX = 0
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of elements in the cnt array. More...

static const unsigned int	VAL_CNT_IDX = 1
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of data points in the cnt array. More...

static const unsigned int	ORDER_CNT_IDX = 2
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of order points in the cnt array. More...

static const unsigned int	HOMY_CNT_IDX = 3
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous y-planes in the cnt array. More...

static const unsigned int	HOMZ_CNT_IDX = 4
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous z-planes in the cnt array. More...

static const unsigned int	HOMS_CNT_IDX = 5
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous strips in the cnt array. More...

static const unsigned int	MAX_CNTS = FieldIOHdf5::HOMS_CNT_IDX + 1
	A helper for FieldIOHdf5::v_Write. Describes the maximum number of items in the cnt array per field definition. More...

static const unsigned int	IDS_IDX_IDX = 0
	A helper for FieldIOHdf5::v_Write. Describes the position of the element IDs within the indexing set. More...

static const unsigned int	DATA_IDX_IDX = 1
	A helper for FieldIOHdf5::v_Write. Describes the position of the data size within the indexing set. More...

static const unsigned int	ORDER_IDX_IDX = 2
	A helper for FieldIOHdf5::v_Write. Describes the position of the element order within the indexing set. More...

static const unsigned int	HOMY_IDX_IDX = 3
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of y-planes within the indexing set. More...

static const unsigned int	HOMZ_IDX_IDX = 4
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of z-planes within the indexing set. More...

static const unsigned int	HOMS_IDX_IDX = 5
	A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous strips within the indexing set. More...

static const unsigned int	MAX_IDXS = FieldIOHdf5::HOMS_IDX_IDX + 1
	A helper for FieldIOHdf5::v_Write. Describes the maximum number of items in the indexing set. More...

static std::string	className
	Name of class. More...

Protected Member Functions
void	v_Write (const std::string &outFile, std::vector< FieldDefinitionsSharedPtr > &fielddefs, std::vector< std::vector< NekDouble > > &fielddata, const FieldMetaDataMap &fieldinfomap=NullFieldMetaDataMap, const bool backup=false) override
	Write a HDF5 file to `outFile` given the field definitions `fielddefs`, field data `fielddata` and metadata `fieldmetadatamap`. More...

void	v_Import (const std::string &infilename, std::vector< FieldDefinitionsSharedPtr > &fielddefs, std::vector< std::vector< NekDouble > > &fielddata=NullVectorNekDoubleVector, FieldMetaDataMap &fieldinfomap=NullFieldMetaDataMap, const Array< OneD, int > &ElementIDs=NullInt1DArray) override
	Import a HDF5 format file. More...

DataSourceSharedPtr	v_ImportFieldMetaData (const std::string &filename, FieldMetaDataMap &fieldmetadatamap) override
	Import field metadata from `filename` and return the data source which wraps `filename`. More...

const std::string &	v_GetClassName () const override
	Get class name. More...

Protected Member Functions inherited from Nektar::LibUtilities::FieldIO
int	CheckFieldDefinition (const FieldDefinitionsSharedPtr &fielddefs)
	Check field definitions for correctness and return storage size. More...

std::vector< unsigned int >	GetNumberOfCoeffsPerElement (const FieldDefinitionsSharedPtr &fielddefs)
	Compute number of data points needed to store expansion inside each element. More...

std::string	SetUpOutput (const std::string outname, bool perRank, bool backup=false)
	Set up the filesystem ready for output. More...

virtual void	v_Write (const std::string &outFile, std::vector< FieldDefinitionsSharedPtr > &fielddefs, std::vector< std::vector< NekDouble > > &fielddata, const FieldMetaDataMap &fieldinfomap, const bool backup=false)=0
	Write out the field information to the file `outFile`. More...

virtual void	v_Import (const std::string &infilename, std::vector< FieldDefinitionsSharedPtr > &fielddefs, std::vector< std::vector< NekDouble > > &fielddata=NullVectorNekDoubleVector, FieldMetaDataMap &fieldinfomap=NullFieldMetaDataMap, const Array< OneD, int > &ElementIDs=NullInt1DArray)=0
	Read field information from the file `infilename`. More...

virtual DataSourceSharedPtr	v_ImportFieldMetaData (const std::string &filename, FieldMetaDataMap &fieldmetadatamap)=0
	Import the metadata from a field file. More...

virtual std::string	v_GetFileEnding () const

virtual const std::string &	v_GetClassName () const =0

Private Member Functions
void	ImportHDF5FieldMetaData (DataSourceSharedPtr dataSource, FieldMetaDataMap &fieldmetadatamap)
	Import field metadata from `dataSource`. More...

void	ImportFieldDef (H5::PListSharedPtr readPL, H5::GroupSharedPtr root, std::vector< uint64_t > &decomps, uint64_t decomp, OffsetHelper offset, std::string group, FieldDefinitionsSharedPtr def)
	Import field definitions from a HDF5 document. More...

Additional Inherited Members
Protected Attributes inherited from Nektar::LibUtilities::FieldIO
LibUtilities::CommSharedPtr	m_comm
	Communicator to use when writing parallel format. More...

bool	m_sharedFilesystem
	Boolean dictating whether we are on a shared filesystem. More...

Detailed Description

Definition at line 173 of file FieldIOHdf5.h.

Constructor & Destructor Documentation

◆ FieldIOHdf5()

Nektar::LibUtilities::FieldIOHdf5::FieldIOHdf5	(	LibUtilities::CommSharedPtr	pComm,
		bool	sharedFilesystem
	)

Construct the FieldIO object for HDF5 output.

Parameters

pComm	Communicator object.
sharedFilesystem	True if this system has a shared filesystem.

Definition at line 143 of file FieldIOHdf5.cpp.

    : FieldIO(pComm, sharedFilesystem)
{
}

◆ ~FieldIOHdf5()

Nektar::LibUtilities::FieldIOHdf5::~FieldIOHdf5 ( )

inlineoverride

Definition at line 217 of file FieldIOHdf5.h.

218 {

219 }

Member Function Documentation

◆ create()

static FieldIOSharedPtr Nektar::LibUtilities::FieldIOHdf5::create	(	LibUtilities::CommSharedPtr	pComm,
		bool	sharedFilesystem
	)

inlinestatic

Creates an instance of this class.

Definition at line 204 of file FieldIOHdf5.h.

    {
        return MemoryManager<FieldIOHdf5>::AllocateSharedPtr(pComm,
                                                             sharedFilesystem);
    }

References Nektar::MemoryManager< DataType >::AllocateSharedPtr().

◆ ImportFieldDef()

void Nektar::LibUtilities::FieldIOHdf5::ImportFieldDef	(	H5::PListSharedPtr	readPL,
		H5::GroupSharedPtr	root,
		std::vector< uint64_t > &	decomps,
		uint64_t	decomp,
		OffsetHelper	offset,
		std::string	group,
		FieldDefinitionsSharedPtr	def
	)

private

Import field definitions from a HDF5 document.

Parameters

readPL	Reading parameter list.
root	Root group containing field definitions.
group	Group name to process.
def	On output contains field definitions.

Definition at line 1191 of file FieldIOHdf5.cpp.

{
    std::stringstream prfx;
    prfx << m_comm->GetRank() << ": FieldIOHdf5::ImportFieldDefsHdf5(): ";
 
    H5::GroupSharedPtr field = root->OpenGroup(group);
    ASSERTL1(field, prfx.str() + "cannot open field group, " + group + '.');
 
    def->m_uniOrder = false;
 
    H5::Group::AttrIterator attrIt  = field->attr_begin();
    H5::Group::AttrIterator attrEnd = field->attr_end();
    for (; attrIt != attrEnd; ++attrIt)
    {
        const std::string &attrName = *attrIt;
        if (attrName == "FIELDS")
        {
            field->GetAttribute(attrName, def->m_fields);
        }
        else if (attrName == "SHAPE")
        {
            std::string shapeString;
            field->GetAttribute(attrName, shapeString);
 
            // check to see if homogeneous expansion and if so
            // strip down the shapeString definition
            size_t loc;
            //---> this finds the first location of 'n'!
            if (shapeString.find("Strips") != std::string::npos)
            {
                def->m_homoStrips = true;
            }
 
            if ((loc = shapeString.find_first_of("-")) != std::string::npos)
            {
                if (shapeString.find("Exp1D") != std::string::npos)
                {
                    def->m_numHomogeneousDir = 1;
                }
                else // HomogeneousExp1D
                {
                    def->m_numHomogeneousDir = 2;
                }
 
                shapeString.erase(loc, shapeString.length());
            }
 
            // get the geometrical shape
            bool valid = false;
            for (unsigned int j = 0; j < SIZE_ShapeType; j++)
            {
                if (ShapeTypeMap[j] == shapeString)
                {
                    def->m_shapeType = (ShapeType)j;
                    valid            = true;
                    break;
                }
            }
 
            ASSERTL0(
                valid,
                prfx.str() +
                    std::string("unable to correctly parse the shape type: ")
                        .append(shapeString)
                        .c_str());
        }
        else if (attrName == "BASIS")
        {
            field->GetAttribute(attrName, def->m_basis);
            // check the basis is in range
            for (auto &bIt : def->m_basis)
            {
                BasisType bt = bIt;
                ASSERTL0(bt >= 0 && bt < SIZE_BasisType,
                         prfx.str() +
                             "unable to correctly parse the basis types.");
            }
        }
        else if (attrName == "HOMOGENEOUSLENGTHS")
        {
            field->GetAttribute(attrName, def->m_homogeneousLengths);
        }
        else if (attrName == "NUMMODESPERDIR")
        {
            std::string numModesPerDir;
            field->GetAttribute(attrName, numModesPerDir);
 
            if (strstr(numModesPerDir.c_str(), "UNIORDER:"))
            {
                def->m_uniOrder = true;
                bool valid      = ParseUtils::GenerateVector(
                    numModesPerDir.substr(9), def->m_numModes);
                ASSERTL0(valid,
                         prfx.str() +
                             "unable to correctly parse the number of modes.");
            }
        }
        else if (attrName == "POINTSTYPE")
        {
            std::string pointsString;
            field->GetAttribute(attrName, pointsString);
            def->m_pointsDef = true;
 
            std::vector<std::string> pointsStrings;
            bool valid =
                ParseUtils::GenerateVector(pointsString, pointsStrings);
            ASSERTL0(valid, prfx.str() +
                                "unable to correctly parse the points types.");
            for (size_t i = 0; i < pointsStrings.size(); i++)
            {
                valid = false;
                for (unsigned int j = 0; j < SIZE_PointsType; j++)
                {
                    if (kPointsTypeStr[j] == pointsStrings[i])
                    {
                        def->m_points.push_back((PointsType)j);
                        valid = true;
                        break;
                    }
                }
 
                ASSERTL0(valid,
                         prfx.str() +
                             std::string(
                                 "unable to correctly parse the points type: ")
                                 .append(pointsStrings[i])
                                 .c_str());
            }
        }
        else if (attrName == "NUMPOINTSPERDIR")
        {
            std::string numPointsPerDir;
            field->GetAttribute(attrName, numPointsPerDir);
            def->m_numPointsDef = true;
 
            bool valid =
                ParseUtils::GenerateVector(numPointsPerDir, def->m_numPoints);
            ASSERTL0(valid,
                     prfx.str() +
                         "unable to correctly parse the number of points.");
        }
        else
        {
            std::string errstr("unknown attribute: ");
            errstr += attrName;
            ASSERTL1(false, prfx.str() + errstr.c_str());
        }
    }
 
    if (def->m_numHomogeneousDir >= 1)
    {
        H5::DataSetSharedPtr homz_dset = root->OpenDataSet("HOMOGENEOUSZIDS");
        H5::DataSpaceSharedPtr homz_fspace = homz_dset->GetSpace();
        uint64_t dsize = decomps[decomp * MAX_DCMPS + HOMZ_DCMP_IDX];
        homz_fspace->SelectRange(offset.homz, dsize);
        homz_dset->Read(def->m_homogeneousZIDs, homz_fspace, readPL);
    }
 
    if (def->m_numHomogeneousDir >= 2)
    {
        H5::DataSetSharedPtr homy_dset = root->OpenDataSet("HOMOGENEOUSYIDS");
        H5::DataSpaceSharedPtr homy_fspace = homy_dset->GetSpace();
        uint64_t dsize = decomps[decomp * MAX_DCMPS + HOMY_DCMP_IDX];
        homy_fspace->SelectRange(offset.homy, dsize);
        homy_dset->Read(def->m_homogeneousYIDs, homy_fspace, readPL);
    }
 
    if (def->m_homoStrips)
    {
        H5::DataSetSharedPtr homs_dset = root->OpenDataSet("HOMOGENEOUSSIDS");
        H5::DataSpaceSharedPtr homs_fspace = homs_dset->GetSpace();
        uint64_t dsize = decomps[decomp * MAX_DCMPS + HOMS_DCMP_IDX];
        homs_fspace->SelectRange(offset.homs, dsize);
        homs_dset->Read(def->m_homogeneousSIDs, homs_fspace, readPL);
    }
 
    if (!def->m_uniOrder)
    {
        H5::DataSetSharedPtr order_dset     = root->OpenDataSet("POLYORDERS");
        H5::DataSpaceSharedPtr order_fspace = order_dset->GetSpace();
        uint64_t dsize = decomps[decomp * MAX_DCMPS + ORDER_DCMP_IDX];
        order_fspace->SelectRange(offset.order, dsize);
        order_dset->Read(def->m_numModes, order_fspace, readPL);
    }
}

Referenced by v_Import().

◆ ImportHDF5FieldMetaData()

void Nektar::LibUtilities::FieldIOHdf5::ImportHDF5FieldMetaData	(	DataSourceSharedPtr	dataSource,
		FieldMetaDataMap &	fieldmetadatamap
	)

private

Import field metadata from dataSource.

Parameters

dataSource	Input datasource, which should be a H5DataSource.
fieldmetadatamap	Resulting field metadata from `dataSource`.

Definition at line 1410 of file FieldIOHdf5.cpp.

{
    H5DataSourceSharedPtr hdf =
        std::static_pointer_cast<H5DataSource>(dataSource);
    H5::GroupSharedPtr master   = hdf->Get()->OpenGroup("NEKTAR");
    H5::GroupSharedPtr metadata = master->OpenGroup("Metadata");
 
    if (metadata)
    {
        H5::Group::AttrIterator param = metadata->attr_begin(),
                                pEnd  = metadata->attr_end();
        for (; param != pEnd; ++param)
        {
            std::string paramString = *param;
            if (paramString != "Provenance")
            {
                std::string paramBodyStr;
                metadata->GetAttribute(paramString, paramBodyStr);
                fieldmetadatamap[paramString] = paramBodyStr;
            }
        }
    }
}

Referenced by v_Import(), and v_ImportFieldMetaData().

◆ v_GetClassName()

const std::string & Nektar::LibUtilities::FieldIOHdf5::v_GetClassName ( ) const

overrideprotectedvirtual

Get class name.

Implements Nektar::LibUtilities::FieldIO.

Definition at line 1399 of file FieldIOHdf5.cpp.

{
    return className;
}

References className.

◆ v_Import()

void Nektar::LibUtilities::FieldIOHdf5::v_Import	(	const std::string &	infilename,
		std::vector< FieldDefinitionsSharedPtr > &	fielddefs,
		std::vector< std::vector< NekDouble > > &	fielddata = `NullVectorNekDoubleVector`,
		FieldMetaDataMap &	fieldinfomap = `NullFieldMetaDataMap`,
		const Array< OneD, int > &	ElementIDs = `NullInt1DArray`
	)

overrideprotectedvirtual

Import a HDF5 format file.

Parameters

finfilename	Input filename
fielddefs	Field definitions of resulting field
fielddata	Field data of resulting field
fieldinfomap	Field metadata of resulting field
ElementIDs	If specified, contains the list of element IDs on this rank. The resulting field definitions will only contain data for the element IDs specified in this array.

Implements Nektar::LibUtilities::FieldIO.

Definition at line 885 of file FieldIOHdf5.cpp.

{
    std::stringstream prfx;
    int nprocs = m_comm->GetSpaceComm()->GetSize();
 
    // Set properties for parallel file access (if we're in parallel)
    H5::PListSharedPtr parallelProps = H5::PList::Default();
    H5::PListSharedPtr readPL        = H5::PList::Default();
    H5::PListSharedPtr readPLInd     = H5::PList::Default();
 
    if (nprocs > 1)
    {
        // Use MPI/O to access the file
        parallelProps = H5::PList::FileAccess();
        parallelProps->SetMpio(m_comm->GetSpaceComm());
        // Use collective IO
        readPL = H5::PList::DatasetXfer();
        readPL->SetDxMpioCollective();
        readPLInd = H5::PList::DatasetXfer();
        readPLInd->SetDxMpioIndependent();
    }
 
    DataSourceSharedPtr dataSource =
        H5DataSource::create(infilename, parallelProps);
 
    // Open the root group of the hdf5 file
    H5DataSourceSharedPtr h5 =
        std::static_pointer_cast<H5DataSource>(dataSource);
    ASSERTL1(h5, prfx.str() + "cannot open HDF5 file.");
    H5::GroupSharedPtr root = h5->Get()->OpenGroup("NEKTAR");
    ASSERTL1(root, prfx.str() + "cannot open root group.");
 
    // Check format version
    unsigned int formatVersion;
    H5::Group::AttrIterator attrIt  = root->attr_begin();
    H5::Group::AttrIterator attrEnd = root->attr_end();
    for (; attrIt != attrEnd; ++attrIt)
    {
        if (*attrIt == "FORMAT_VERSION")
        {
            break;
        }
    }
 
    ASSERTL0(attrIt != attrEnd,
             "Unable to determine Nektar++ HDF5 file version");
    root->GetAttribute("FORMAT_VERSION", formatVersion);
 
    ASSERTL0(formatVersion <= FORMAT_VERSION,
             "File format if " + infilename +
                 " is higher than supported in "
                 "this version of Nektar++");
 
    // Open the datasets
    H5::DataSetSharedPtr decomps_dset = root->OpenDataSet("DECOMPOSITION");
    ASSERTL1(decomps_dset, prfx.str() + "cannot open DECOMPOSITION dataset.");
 
    H5::DataSetSharedPtr ids_dset = root->OpenDataSet("ELEMENTIDS");
    ASSERTL1(ids_dset, prfx.str() + "cannot open ELEMENTIDS dataset.");
 
    H5::DataSetSharedPtr data_dset = root->OpenDataSet("DATA");
    ASSERTL1(data_dset, prfx.str() + "cannot open DATA dataset.");
 
    // Open the dataset file spaces
    H5::DataSpaceSharedPtr decomps_fspace = decomps_dset->GetSpace();
    ASSERTL1(decomps_fspace,
             prfx.str() + "cannot open DECOMPOSITION filespace.");
 
    H5::DataSpaceSharedPtr ids_fspace = ids_dset->GetSpace();
    ASSERTL1(ids_fspace, prfx.str() + "cannot open ELEMENTIDS filespace.");
 
    H5::DataSpaceSharedPtr data_fspace = data_dset->GetSpace();
    ASSERTL1(data_fspace, prfx.str() + "cannot open DATA filespace.");
 
    // Read entire IDS data set to get list of global IDs.
    std::vector<uint64_t> ids;
 
    ids_dset->Read(ids, ids_fspace, readPL);
 
    std::unordered_set<uint64_t> toread;
    if (ElementIDs != NullInt1DArray)
    {
        for (uint64_t i = 0; i < ElementIDs.size(); ++i)
        {
            toread.insert(ElementIDs[i]);
        }
    }
 
    std::vector<uint64_t> decomps;
    decomps_dset->Read(decomps, decomps_fspace, readPL);
 
    size_t nDecomps = decomps.size() / MAX_DCMPS;
 
    // Mapping from each decomposition to offsets in the data array.
    std::vector<OffsetHelper> decompsToOffsets(nDecomps);
 
    // Mapping from each decomposition to a vector of element IDs. Note this has
    // to be unsigned int, since that's what we use in FieldDefinitions.
    std::map<uint64_t, std::vector<unsigned int>> decompsToElmts;
 
    // Mapping from each group's hash to each of the decompositions.
    std::map<uint64_t, std::set<uint64_t>> groupsToDecomps;
 
    // True if we are pulling element IDs from ElementIDs.
    bool selective = toread.size() > 0;
 
    // Counters for data offsets
    OffsetHelper running;
 
    for (size_t i = 0, cnt = 0, cnt2 = 0; i < nDecomps; ++i, cnt += MAX_DCMPS)
    {
        uint64_t nElmt     = decomps[cnt + ELEM_DCMP_IDX];
        uint64_t groupHash = decomps[cnt + HASH_DCMP_IDX];
 
        // Number of elements in this decomposition that this process needs
        uint64_t nElmtSelective = 0;
 
        // Check if we should keep any elements in this decomposition
        if (selective)
        {
            for (size_t j = 0; j < nElmt; ++j)
            {
                uint64_t elmtId = ids[cnt2 + j];
                if (toread.find(elmtId) != toread.end())
                {
                    nElmtSelective += 1;
                }
            }
        }
        else
        {
            nElmtSelective = nElmt;
        }
 
        if (nElmtSelective > 0)
        {
            groupsToDecomps[groupHash].insert(i);
        }
 
        // All element IDs in this decomposition
        std::vector<unsigned int> tmp2(nElmt);
        for (size_t j = 0; j < nElmt; ++j)
        {
            tmp2[j] = ids[cnt2 + j];
        }
 
        cnt2 += nElmt;
 
        decompsToElmts[i]   = tmp2;
        decompsToOffsets[i] = running;
 
        //
        // TODO: Will this update the OffsetHelper in decompsToOffsets? (copy
        // constructor?)
        //
        running.data += decomps[cnt + VAL_DCMP_IDX];
        running.order += decomps[cnt + ORDER_DCMP_IDX];
        running.homy += decomps[cnt + HOMY_DCMP_IDX];
        running.homz += decomps[cnt + HOMZ_DCMP_IDX];
        running.homs += decomps[cnt + HOMS_DCMP_IDX];
    }
 
    for (auto &gIt : groupsToDecomps)
    {
        // Select region from dataset for this decomposition.
        for (auto &sIt : gIt.second)
        {
            // Convert group name to string
            auto groupName = std::to_string(gIt.first);
 
            FieldDefinitionsSharedPtr fielddef =
                MemoryManager<FieldDefinitions>::AllocateSharedPtr();
            ImportFieldDef(readPLInd, root, decomps, sIt, decompsToOffsets[sIt],
                           groupName, fielddef);
 
            fielddef->m_elementIDs = decompsToElmts[sIt];
            //
            // TODO: Fix the case with 0 elements!
            //
            fielddefs.push_back(fielddef);
 
            if (fielddata != NullVectorNekDoubleVector)
            {
                if (selective)
                {
                    // Determine number of modes (coefficients) per element
                    std::vector<unsigned int> coeffsPerElmt{
                        GetNumberOfCoeffsPerElement(fielddef)};
 
                    // Selected element IDs
                    std::vector<unsigned int> newElementIDs;
                    std::vector<unsigned int> newNumModes;
                    std::vector<hsize_t> dataIdxToRead;
 
                    {
                        size_t offset   = 0;
                        size_t numbasis = fielddef->m_basis.size();
 
                        // Loop through all elements in this decomposition
 
                        for (size_t i = 0; i < fielddef->m_elementIDs.size();
                             ++i)
                        {
                            // Check if we need data for this element
                            if (toread.find(fielddef->m_elementIDs[i]) !=
                                toread.end())
                            {
                                newElementIDs.push_back(
                                    fielddef->m_elementIDs[i]);
 
                                for (size_t j = 0; j < coeffsPerElmt[i]; ++j)
                                {
                                    dataIdxToRead.push_back(
                                        decompsToOffsets[sIt].data + offset +
                                        j);
                                }
 
                                if (fielddef->m_uniOrder == false)
                                {
                                    for (size_t j = 0; j < numbasis; ++j)
                                    {
                                        newNumModes.push_back(
                                            fielddef
                                                ->m_numModes[i * numbasis + j]);
                                    }
                                }
                            }
 
                            offset += coeffsPerElmt[i];
                        }
 
                        // Add indices for all remaining fields (variables)
                        // We assume that all fields are stored with the same
                        // polynomial order
                        const size_t nDataPoints = dataIdxToRead.size();
 
                        for (size_t i = 1; i < fielddef->m_fields.size(); ++i)
                        {
                            for (size_t j = 0; j < nDataPoints; ++j)
                            {
                                dataIdxToRead.push_back(dataIdxToRead[j] +
                                                        i * offset);
                            }
                        }
                    }
 
                    fielddef->m_elementIDs = newElementIDs;
                    if (fielddef->m_uniOrder == false)
                    {
                        fielddef->m_numModes = newNumModes;
                    }
 
                    std::vector<NekDouble> decompFieldData;
 
                    data_fspace->ClearRange();
                    data_fspace->SetSelection(dataIdxToRead.size(),
                                              dataIdxToRead);
 
                    data_dset->Read(decompFieldData, data_fspace, readPLInd);
                    ASSERTL0(decompFieldData.size() ==
                                 CheckFieldDefinition(fielddef) *
                                     fielddef->m_fields.size(),
                             "FieldIOHdf5: input data is not the same length "
                             "as header information.");
                    fielddata.push_back(decompFieldData);
                }
                else
                {
                    std::vector<NekDouble> decompFieldData;
 
                    uint64_t nElemVals =
                        decomps[sIt * MAX_DCMPS + VAL_DCMP_IDX];
                    uint64_t nFieldVals = nElemVals;
 
                    data_fspace->ClearRange();
                    data_fspace->SelectRange(decompsToOffsets[sIt].data,
                                             nFieldVals);
 
                    data_dset->Read(decompFieldData, data_fspace, readPLInd);
                    ASSERTL0(decompFieldData.size() ==
                                 CheckFieldDefinition(fielddef) *
                                     fielddef->m_fields.size(),
                             "FieldIOHdf5: input data is not the same length "
                             "as header information.");
                    fielddata.push_back(decompFieldData);
                }
            }
        }
    }
 
    ImportHDF5FieldMetaData(dataSource, fieldinfomap);
    m_comm->GetSpaceComm()->Block();
}

◆ v_ImportFieldMetaData()

DataSourceSharedPtr Nektar::LibUtilities::FieldIOHdf5::v_ImportFieldMetaData	(	const std::string &	filename,
		FieldMetaDataMap &	fieldmetadatamap
	)

overrideprotectedvirtual

Import field metadata from filename and return the data source which wraps filename.

Parameters

filename	Input filename.
fieldmetadatamap	Resulting field metadata from `dataSource`.

Implements Nektar::LibUtilities::FieldIO.

Definition at line 1389 of file FieldIOHdf5.cpp.

{
    H5::PListSharedPtr parallelProps = H5::PList::Default();
    DataSourceSharedPtr ans = H5DataSource::create(filename, parallelProps);
    ImportHDF5FieldMetaData(ans, fieldmetadatamap);
    return ans;
}

References Nektar::LibUtilities::H5DataSource::create(), Nektar::LibUtilities::H5::PList::Default(), and ImportHDF5FieldMetaData().

◆ v_Write()

void Nektar::LibUtilities::FieldIOHdf5::v_Write	(	const std::string &	outFile,
		std::vector< FieldDefinitionsSharedPtr > &	fielddefs,
		std::vector< std::vector< NekDouble > > &	fielddata,
		const FieldMetaDataMap &	fieldmetadatamap = `NullFieldMetaDataMap`,
		const bool	backup = `false`
	)

overrideprotectedvirtual

Write a HDF5 file to outFile given the field definitions fielddefs, field data fielddata and metadata fieldmetadatamap.

The writing strategy for HDF5 output is as follows:

Each rank determines the amount of data needed to be written into each dataset.
Each rank communicates its decomposition information to the root process.
The root processor initialises the output structure, writes the decomposition dataset and all the field definition information.
Other ranks may have field definitions that do not belong to the root process, in which case they open the file and append this (since attributes cannot be written in parallel).
Each of the other ranks writes their data contributions to the rest of the set.

Parameters

outFile	Output filename.
fielddefs	Input field definitions.
fielddata	Input field data.
fieldmetadatamap	Field metadata.

Implements Nektar::LibUtilities::FieldIO.

Definition at line 171 of file FieldIOHdf5.cpp.

{
    std::stringstream prfx;
    prfx << m_comm->GetRank() << ": FieldIOHdf5::v_Write(): ";
    double tm0 = 0.0, tm1 = 0.0;
 
    if (m_comm->GetRank() == 0)
    {
        tm0 = m_comm->Wtime();
    }
 
    SetUpOutput(outFile, false, backup);
 
    // We make a number of assumptions in this code:
    //   1. All element ids have the same type: unsigned int
    //   2. All elements within a given field have the same number of values
    //   3. All element values have the same type, NekDouble
 
    // Determine the root MPI process, i.e., the lowest ranked process handling
    // nMaxFields fields, that will be responsible for writing our file.
    ASSERTL1(fielddefs.size() == fielddata.size(),
             prfx.str() + "fielddefs and fielddata have incompatible lengths.");
 
    size_t nFields    = fielddefs.size();
    size_t nMaxFields = nFields;
    m_comm->GetSpaceComm()->AllReduce(nMaxFields, LibUtilities::ReduceMax);
 
    int root_rank = -1;
    int nprocs    = m_comm->GetSpaceComm()->GetSize();
    bool amRoot   = false;
    LibUtilities::CommSharedPtr max_fields_comm;
 
    if (nprocs > 1)
    {
        max_fields_comm = m_comm->GetSpaceComm()->CommCreateIf(
            (nFields == nMaxFields) ? 1 : 0);
    }
    else
    {
        max_fields_comm = m_comm->GetSpaceComm();
    }
 
    if (max_fields_comm)
    {
        int rank  = m_comm->GetSpaceComm()->GetRank();
        root_rank = rank;
        max_fields_comm->AllReduce(root_rank, LibUtilities::ReduceMin);
        amRoot = (rank == root_rank);
        if (!amRoot)
        {
            root_rank = -1;
        }
    }
 
    m_comm->GetSpaceComm()->AllReduce(root_rank, LibUtilities::ReduceMax);
    ASSERTL1(root_rank >= 0 && root_rank < nprocs,
             prfx.str() + "invalid root rank.");
 
    std::vector<uint64_t> decomps(nMaxFields * MAX_DCMPS, 0);
    std::vector<uint64_t> all_hashes(nMaxFields * nprocs, 0);
    std::vector<uint64_t> cnts(MAX_CNTS, 0);
    std::vector<std::string> fieldNames(nFields);
    std::vector<std::string> shapeStrings(nFields);
    std::vector<std::vector<NekDouble>> homoLengths(nFields);
    std::vector<std::vector<unsigned int>> homoSIDs(nFields), homoYIDs(nFields),
        homoZIDs(nFields);
    std::vector<std::vector<unsigned int>> numModesPerDirVar(nFields);
    std::vector<std::string> numModesPerDirUni(nFields);
 
    int homDim   = -1;
    int varOrder = 0;
 
    for (int f = 0; f < nFields; ++f)
    {
        if (!fielddefs[f]->m_uniOrder)
        {
            varOrder = 1;
            break;
        }
    }
 
    m_comm->GetSpaceComm()->AllReduce(varOrder, LibUtilities::ReduceMax);
 
    // Calculate the total number of elements handled by this MPI process and
    // the total number of bytes required to store the elements. Base the name
    // of each field on the hash of the field definition.
    for (int f = 0; f < nFields; ++f)
    {
        ASSERTL1(fielddata[f].size() > 0,
                 prfx.str() +
                     "fielddata vector must contain at least one value.");
        ASSERTL1(fielddata[f].size() == fielddefs[f]->m_fields.size() *
                                            CheckFieldDefinition(fielddefs[f]),
                 prfx.str() + "fielddata vector has invalid size.");
 
        std::size_t nFieldElems = fielddefs[f]->m_elementIDs.size();
        std::size_t nElemVals   = fielddata[f].size();
 
        decomps[f * MAX_DCMPS + ELEM_DCMP_IDX] = nFieldElems;
        decomps[f * MAX_DCMPS + VAL_DCMP_IDX]  = nElemVals;
 
        cnts[ELEM_CNT_IDX] += nFieldElems;
        cnts[VAL_CNT_IDX] += nElemVals;
 
        // Hash the field specification
        std::stringstream hashStream;
        size_t nSubFields = fielddefs[f]->m_fields.size();
        for (size_t sf = 0; sf < nSubFields; ++sf)
        {
            hashStream << fielddefs[f]->m_fields[sf];
        }
 
        nSubFields = fielddefs[f]->m_basis.size();
        for (size_t sf = 0; sf < nSubFields; ++sf)
        {
            hashStream << fielddefs[f]->m_basis[sf];
        }
 
        // Determine SHAPE attribute
        std::stringstream shapeStringStream;
        shapeStringStream << ShapeTypeMap[fielddefs[f]->m_shapeType];
 
        if (fielddefs[f]->m_numHomogeneousDir > 0)
        {
            if (homDim == -1)
            {
                homDim = fielddefs[f]->m_numHomogeneousDir;
            }
 
            ASSERTL1(homDim == fielddefs[f]->m_numHomogeneousDir,
                     "HDF5 does not support variable homogeneous directions in "
                     "the same file.");
 
            shapeStringStream << "-HomogenousExp"
                              << fielddefs[f]->m_numHomogeneousDir << "D";
        }
 
        if (fielddefs[f]->m_homoStrips)
        {
            shapeStringStream << "-Strips";
        }
 
        shapeStrings[f] = shapeStringStream.str();
        hashStream << shapeStringStream.str();
 
        // Determine HOMOGENEOUS attributes
        if (fielddefs[f]->m_numHomogeneousDir)
        {
            nSubFields = fielddefs[f]->m_homogeneousLengths.size();
            homoLengths[f].resize(nSubFields);
            for (size_t sf = 0; sf < nSubFields; ++sf)
            {
                NekDouble len = fielddefs[f]->m_homogeneousLengths[sf];
                hashStream << len;
                homoLengths[f][sf] = len;
            }
 
            nSubFields = fielddefs[f]->m_homogeneousYIDs.size();
            if (nSubFields > 0)
            {
                homoYIDs[f].resize(nSubFields);
                decomps[f * MAX_DCMPS + HOMY_DCMP_IDX] = nSubFields;
                cnts[HOMY_CNT_IDX] += nSubFields;
                for (size_t sf = 0; sf < nSubFields; ++sf)
                {
                    homoYIDs[f][sf] = fielddefs[f]->m_homogeneousYIDs[sf];
                }
            }
 
            nSubFields = fielddefs[f]->m_homogeneousZIDs.size();
            if (nSubFields > 0)
            {
                homoZIDs[f].resize(nSubFields);
                decomps[f * MAX_DCMPS + HOMZ_DCMP_IDX] = nSubFields;
                cnts[HOMZ_CNT_IDX] += nSubFields;
                for (size_t sf = 0; sf < nSubFields; ++sf)
                {
                    homoZIDs[f][sf] = fielddefs[f]->m_homogeneousZIDs[sf];
                }
            }
 
            nSubFields = fielddefs[f]->m_homogeneousSIDs.size();
            if (nSubFields > 0)
            {
                homoSIDs[f].resize(nSubFields);
                decomps[f * MAX_DCMPS + HOMS_DCMP_IDX] = nSubFields;
                cnts[HOMS_CNT_IDX] += nSubFields;
                for (size_t sf = 0; sf < nSubFields; ++sf)
                {
                    homoSIDs[f][sf] = fielddefs[f]->m_homogeneousSIDs[sf];
                }
            }
        }
 
        if (fielddefs[f]->m_uniOrder)
        {
            std::vector<unsigned int> elemModes(fielddefs[f]->m_basis.size());
 
            for (size_t i = 0; i < fielddefs[f]->m_basis.size(); ++i)
            {
                elemModes[i] = fielddefs[f]->m_numModes[i];
            }
 
            if (varOrder)
            {
                for (size_t i = 0; i < nFieldElems; ++i)
                {
                    std::copy(elemModes.begin(), elemModes.end(),
                              std::back_inserter(numModesPerDirVar[f]));
                }
                decomps[f * MAX_DCMPS + ORDER_DCMP_IDX] =
                    nFieldElems * elemModes.size();
                cnts[ORDER_CNT_IDX] += nFieldElems * elemModes.size();
            }
            else
            {
                std::stringstream numModesStringStream;
                numModesStringStream << "UNIORDER:";
                for (size_t i = 0; i < elemModes.size(); i++)
                {
                    if (i > 0)
                    {
                        numModesStringStream << ",";
                    }
                    numModesStringStream << elemModes[i];
                }
 
                numModesPerDirUni[f] = numModesStringStream.str();
                hashStream << numModesPerDirUni[f];
            }
        }
        else
        {
            numModesPerDirVar[f] = fielddefs[f]->m_numModes;
            decomps[f * MAX_DCMPS + ORDER_DCMP_IDX] =
                fielddefs[f]->m_numModes.size();
            cnts[ORDER_CNT_IDX] += fielddefs[f]->m_numModes.size();
        }
 
        std::hash<std::string> string_hasher;
        std::stringstream fieldNameStream;
        uint64_t fieldDefHash = string_hasher(hashStream.str());
 
        decomps[f * MAX_DCMPS + HASH_DCMP_IDX] = fieldDefHash;
        all_hashes[m_comm->GetSpaceComm()->GetRank() * nMaxFields + f] =
            fieldDefHash;
 
        fieldNameStream << fieldDefHash;
        fieldNames[f] = fieldNameStream.str();
    }
 
    // Gather information from all MPI processes
    std::vector<uint64_t> all_cnts =
        m_comm->GetSpaceComm()->Gather(root_rank, cnts);
    std::vector<uint64_t> all_idxs(nprocs * MAX_IDXS, 0);
    std::vector<uint64_t> all_decomps =
        m_comm->GetSpaceComm()->Gather(root_rank, decomps);
    std::vector<uint64_t> all_dsetsize(MAX_CNTS, 0);
 
    // The root rank creates the file layout from scratch
    if (amRoot)
    {
        H5::FileSharedPtr outfile = H5::File::Create(outFile, H5F_ACC_TRUNC);
        ASSERTL1(outfile, prfx.str() + "cannot create HDF5 file.");
        H5::GroupSharedPtr root = outfile->CreateGroup("NEKTAR");
        ASSERTL1(root, prfx.str() + "cannot create root group.");
        TagWriterSharedPtr info_writer(new H5TagWriter(root));
        AddInfoTag(info_writer, fieldmetadatamap);
 
        // Record file format version as attribute in main group.
        root->SetAttribute("FORMAT_VERSION", FORMAT_VERSION);
 
        // Calculate the indexes to be used by each MPI process when reading the
        // IDS and DATA datasets
        size_t nTotElems = 0, nTotVals = 0, nTotOrder = 0;
        size_t nTotHomY = 0, nTotHomZ = 0, nTotHomS = 0;
        for (int r = 0; r < nprocs; ++r)
        {
            all_idxs[r * MAX_IDXS + IDS_IDX_IDX]   = nTotElems;
            all_idxs[r * MAX_IDXS + DATA_IDX_IDX]  = nTotVals;
            all_idxs[r * MAX_IDXS + ORDER_IDX_IDX] = nTotOrder;
            all_idxs[r * MAX_IDXS + HOMY_IDX_IDX]  = nTotHomY;
            all_idxs[r * MAX_IDXS + HOMZ_IDX_IDX]  = nTotHomZ;
            all_idxs[r * MAX_IDXS + HOMS_IDX_IDX]  = nTotHomS;
 
            nTotElems += all_cnts[r * MAX_CNTS + ELEM_CNT_IDX];
            nTotVals += all_cnts[r * MAX_CNTS + VAL_CNT_IDX];
            nTotOrder += all_cnts[r * MAX_CNTS + ORDER_CNT_IDX];
            nTotHomY += all_cnts[r * MAX_CNTS + HOMY_CNT_IDX];
            nTotHomZ += all_cnts[r * MAX_CNTS + HOMZ_CNT_IDX];
            nTotHomS += all_cnts[r * MAX_CNTS + HOMS_CNT_IDX];
        }
 
        all_dsetsize[ELEM_CNT_IDX]  = nTotElems;
        all_dsetsize[VAL_CNT_IDX]   = nTotVals;
        all_dsetsize[ORDER_CNT_IDX] = nTotOrder;
        all_dsetsize[HOMY_CNT_IDX]  = nTotHomY;
        all_dsetsize[HOMZ_CNT_IDX]  = nTotHomZ;
        all_dsetsize[HOMS_CNT_IDX]  = nTotHomS;
 
        // Create DECOMPOSITION dataset: basic field info for each MPI process
        H5::DataTypeSharedPtr decomps_type =
            H5::DataType::OfObject(all_decomps[0]);
        H5::DataSpaceSharedPtr decomps_space =
            H5::DataSpace::OneD(all_decomps.size());
        H5::DataSetSharedPtr decomps_dset =
            root->CreateDataSet("DECOMPOSITION", decomps_type, decomps_space);
        ASSERTL1(decomps_dset,
                 prfx.str() + "cannot create DECOMPOSITION dataset.");
 
        // Create IDS dataset: element ids
        H5::DataTypeSharedPtr ids_type =
            H5::DataType::OfObject(fielddefs[0]->m_elementIDs[0]);
        H5::DataSpaceSharedPtr ids_space = H5::DataSpace::OneD(nTotElems);
        H5::DataSetSharedPtr ids_dset =
            root->CreateDataSet("ELEMENTIDS", ids_type, ids_space);
        ASSERTL1(ids_dset, prfx.str() + "cannot create ELEMENTIDS dataset.");
 
        // Create DATA dataset: element data
        H5::DataTypeSharedPtr data_type =
            H5::DataType::OfObject(fielddata[0][0]);
        H5::DataSpaceSharedPtr data_space = H5::DataSpace::OneD(nTotVals);
        H5::DataSetSharedPtr data_dset =
            root->CreateDataSet("DATA", data_type, data_space);
        ASSERTL1(data_dset, prfx.str() + "cannot create DATA dataset.");
 
        // Create HOMOGENEOUSYIDS dataset: homogeneous y-plane IDs
        if (nTotHomY > 0)
        {
            H5::DataTypeSharedPtr homy_type =
                H5::DataType::OfObject(homoYIDs[0][0]);
            H5::DataSpaceSharedPtr homy_space = H5::DataSpace::OneD(nTotHomY);
            H5::DataSetSharedPtr homy_dset =
                root->CreateDataSet("HOMOGENEOUSYIDS", homy_type, homy_space);
            ASSERTL1(homy_dset,
                     prfx.str() + "cannot create HOMOGENEOUSYIDS dataset.");
        }
 
        // Create HOMOGENEOUSYIDS dataset: homogeneous z-plane IDs
        if (nTotHomZ > 0)
        {
            H5::DataTypeSharedPtr homz_type =
                H5::DataType::OfObject(homoZIDs[0][0]);
            H5::DataSpaceSharedPtr homz_space = H5::DataSpace::OneD(nTotHomZ);
            H5::DataSetSharedPtr homz_dset =
                root->CreateDataSet("HOMOGENEOUSZIDS", homz_type, homz_space);
            ASSERTL1(homz_dset,
                     prfx.str() + "cannot create HOMOGENEOUSZIDS dataset.");
        }
 
        // Create HOMOGENEOUSSIDS dataset: homogeneous strip IDs
        if (nTotHomS > 0)
        {
            H5::DataTypeSharedPtr homs_type =
                H5::DataType::OfObject(homoSIDs[0][0]);
            H5::DataSpaceSharedPtr homs_space = H5::DataSpace::OneD(nTotHomS);
            H5::DataSetSharedPtr homs_dset =
                root->CreateDataSet("HOMOGENEOUSSIDS", homs_type, homs_space);
            ASSERTL1(homs_dset,
                     prfx.str() + "cannot create HOMOGENEOUSSIDS dataset.");
        }
 
        // Create POLYORDERS dataset: elemental polynomial orders
        if (varOrder)
        {
            H5::DataTypeSharedPtr order_type =
                H5::DataType::OfObject(numModesPerDirVar[0][0]);
            H5::DataSpaceSharedPtr order_space = H5::DataSpace::OneD(nTotOrder);
            H5::DataSetSharedPtr order_dset =
                root->CreateDataSet("POLYORDERS", order_type, order_space);
            ASSERTL1(order_dset,
                     prfx.str() + "cannot create POLYORDERS dataset.");
        }
    }
 
    m_comm->GetSpaceComm()->Bcast(all_dsetsize, root_rank);
 
    // Datasets, root group and HDF5 file are all closed automatically since
    // they are now out of scope. Now we need to determine which process will
    // write the group representing the field description in the HDF5 file. This
    // next block of code performs this by finding all unique hashes and then
    // determining one process that will create (possibly more than one) group
    // for that hash. An alternative would be to communicate the field
    // information to the root processor, but this is a bit convoluted.
 
    // This set stores the unique hashes.
    std::set<uint64_t> hashToProc;
 
    // This map takes ranks to hashes this process will write.
    std::map<int, std::vector<uint64_t>> writingProcs;
 
    // Gather all field hashes to every processor.
    m_comm->GetSpaceComm()->AllReduce(all_hashes, LibUtilities::ReduceMax);
 
    for (int n = 0; n < nprocs; ++n)
    {
        for (int i = 0; i < nMaxFields; ++i)
        {
            uint64_t hash = all_hashes[n * nMaxFields + i];
 
            // Note hash can be zero if, on this process, nFields < nMaxFields.
            if (hashToProc.find(hash) != hashToProc.end() || hash == 0)
            {
                continue;
            }
            hashToProc.insert(hash);
            writingProcs[n].push_back(hash);
        }
    }
 
    // Having constructed the map, go ahead and write the attributes out.
    for (auto &sIt : writingProcs)
    {
        int rank = sIt.first;
 
        // Write out this rank's groups.
        if (m_comm->GetSpaceComm()->GetRank() == rank)
        {
            H5::PListSharedPtr serialProps = H5::PList::Default();
            H5::PListSharedPtr writeSR     = H5::PList::Default();
 
            // Reopen the file
            H5::FileSharedPtr outfile =
                H5::File::Open(outFile, H5F_ACC_RDWR, serialProps);
            ASSERTL1(outfile, prfx.str() + "cannot open HDF5 file.");
            H5::GroupSharedPtr root = outfile->OpenGroup("NEKTAR");
            ASSERTL1(root, prfx.str() + "cannot open root group.");
 
            // Write a HDF5 group for each field
            hashToProc.clear();
            for (int i = 0; i < sIt.second.size(); ++i)
            {
                for (int f = 0; f < nFields; ++f)
                {
                    if (sIt.second[i] !=
                            all_hashes[m_comm->GetSpaceComm()->GetRank() *
                                           nMaxFields +
                                       f] ||
                        hashToProc.find(sIt.second[i]) != hashToProc.end())
                    {
                        continue;
                    }
 
                    hashToProc.insert(sIt.second[i]);
 
                    // Just in case we've already written this
                    H5::GroupSharedPtr field_group =
                        root->CreateGroup(fieldNames[f]);
                    ASSERTL1(field_group,
                             prfx.str() + "cannot create field group.");
                    field_group->SetAttribute("FIELDS", fielddefs[f]->m_fields);
                    field_group->SetAttribute("BASIS", fielddefs[f]->m_basis);
                    field_group->SetAttribute("SHAPE", shapeStrings[f]);
 
                    if (homoLengths[f].size() > 0)
                    {
                        field_group->SetAttribute("HOMOGENEOUSLENGTHS",
                                                  homoLengths[f]);
                    }
 
                    // If the field has only uniform order, we write the order
                    // into the NUMMODESPERDIR attribute. Otherwise, we'll go
                    // ahead and assume everything is mixed and fix this in the
                    // read later if required.
                    if (!varOrder)
                    {
                        field_group->SetAttribute("NUMMODESPERDIR",
                                                  numModesPerDirUni[f]);
                    }
                    else
                    {
                        std::string numModesPerDir = "MIXORDER";
                        field_group->SetAttribute("NUMMODESPERDIR",
                                                  numModesPerDir);
                    }
                }
            }
        }
 
        // We block to avoid more than one processor opening the file at a time.
        m_comm->GetSpaceComm()->Block();
    }
 
    // Write the DECOMPOSITION dataset
    if (amRoot)
    {
        H5::PListSharedPtr serialProps = H5::PList::Default();
        H5::PListSharedPtr writeSR     = H5::PList::Default();
 
        // Reopen the file
        H5::FileSharedPtr outfile =
            H5::File::Open(outFile, H5F_ACC_RDWR, serialProps);
        ASSERTL1(outfile, prfx.str() + "cannot open HDF5 file.");
        H5::GroupSharedPtr root = outfile->OpenGroup("NEKTAR");
        ASSERTL1(root, prfx.str() + "cannot open root group.");
 
        // Write the DECOMPOSITION dataset
        H5::DataSetSharedPtr decomps_dset = root->OpenDataSet("DECOMPOSITION");
        ASSERTL1(decomps_dset,
                 prfx.str() + "cannot open DECOMPOSITION dataset.");
 
        H5::DataSpaceSharedPtr decomps_fspace = decomps_dset->GetSpace();
        ASSERTL1(decomps_fspace,
                 prfx.str() + "cannot open DECOMPOSITION filespace.");
 
        decomps_fspace->SelectRange(0, all_decomps.size());
        decomps_dset->Write(all_decomps, decomps_fspace, writeSR);
    }
 
    // Initialise the dataset indexes for all MPI processes
    std::vector<uint64_t> idx =
        m_comm->GetSpaceComm()->Scatter(root_rank, all_idxs);
    uint64_t ids_i   = idx[IDS_IDX_IDX];
    uint64_t data_i  = idx[DATA_IDX_IDX];
    uint64_t order_i = idx[ORDER_IDX_IDX];
    uint64_t homy_i  = idx[HOMY_IDX_IDX];
    uint64_t homz_i  = idx[HOMZ_IDX_IDX];
    uint64_t homs_i  = idx[HOMS_IDX_IDX];
 
    // Set properties for parallel file access (if we're in parallel)
    H5::PListSharedPtr parallelProps = H5::PList::Default();
    H5::PListSharedPtr writePL       = H5::PList::Default();
    if (nprocs > 1)
    {
        // Use MPI/O to access the file
        parallelProps = H5::PList::FileAccess();
        parallelProps->SetMpio(m_comm->GetSpaceComm());
        // Use collective IO
        writePL = H5::PList::DatasetXfer();
        writePL->SetDxMpioCollective();
    }
 
    // Reopen the file
    H5::FileSharedPtr outfile =
        H5::File::Open(outFile, H5F_ACC_RDWR, parallelProps);
    ASSERTL1(outfile, prfx.str() + "cannot open HDF5 file.");
    H5::GroupSharedPtr root = outfile->OpenGroup("NEKTAR");
    ASSERTL1(root, prfx.str() + "cannot open root group.");
 
    m_comm->GetSpaceComm()->Block();
 
    // all HDF5 groups have now been created. Open the IDS dataset and
    // associated data space
    H5::DataSetSharedPtr ids_dset = root->OpenDataSet("ELEMENTIDS");
    ASSERTL1(ids_dset, prfx.str() + "cannot open ELEMENTIDS dataset.");
    H5::DataSpaceSharedPtr ids_fspace = ids_dset->GetSpace();
    ASSERTL1(ids_fspace, prfx.str() + "cannot open ELEMENTIDS filespace.");
 
    // Open the DATA dataset and associated data space
    H5::DataSetSharedPtr data_dset = root->OpenDataSet("DATA");
    ASSERTL1(data_dset, prfx.str() + "cannot open DATA dataset.");
    H5::DataSpaceSharedPtr data_fspace = data_dset->GetSpace();
    ASSERTL1(data_fspace, prfx.str() + "cannot open DATA filespace.");
 
    // Open the optional datasets and data spaces.
    H5::DataSetSharedPtr order_dset, homy_dset, homz_dset, homs_dset;
    H5::DataSpaceSharedPtr order_fspace, homy_fspace, homz_fspace, homs_fspace;
 
    if (all_dsetsize[ORDER_CNT_IDX])
    {
        order_dset = root->OpenDataSet("POLYORDERS");
        ASSERTL1(order_dset, prfx.str() + "cannot open POLYORDERS dataset.");
        order_fspace = order_dset->GetSpace();
        ASSERTL1(order_fspace,
                 prfx.str() + "cannot open POLYORDERS filespace.");
    }
 
    if (all_dsetsize[HOMY_CNT_IDX])
    {
        homy_dset = root->OpenDataSet("HOMOGENEOUSYIDS");
        ASSERTL1(homy_dset,
                 prfx.str() + "cannot open HOMOGENEOUSYIDS dataset.");
        homy_fspace = homy_dset->GetSpace();
        ASSERTL1(homy_fspace,
                 prfx.str() + "cannot open HOMOGENEOUSYIDS filespace.");
    }
 
    if (all_dsetsize[HOMZ_CNT_IDX])
    {
        homz_dset = root->OpenDataSet("HOMOGENEOUSZIDS");
        ASSERTL1(homz_dset,
                 prfx.str() + "cannot open HOMOGENEOUSZIDS dataset.");
        homz_fspace = homz_dset->GetSpace();
        ASSERTL1(homz_fspace,
                 prfx.str() + "cannot open HOMOGENEOUSZIDS filespace.");
    }
 
    if (all_dsetsize[HOMS_CNT_IDX])
    {
        homs_dset = root->OpenDataSet("HOMOGENEOUSSIDS");
        ASSERTL1(homs_dset,
                 prfx.str() + "cannot open HOMOGENEOUSSIDS dataset.");
        homs_fspace = homs_dset->GetSpace();
        ASSERTL1(homs_fspace,
                 prfx.str() + "cannot open HOMOGENEOUSSIDS filespace.");
    }
 
    // Write the data
    for (int f = 0; f < nFields; ++f)
    {
        // write the element ids
        std::size_t nFieldElems = fielddefs[f]->m_elementIDs.size();
        ids_fspace->SelectRange(ids_i, nFieldElems);
        ids_dset->Write(fielddefs[f]->m_elementIDs, ids_fspace, writePL);
        ids_i += nFieldElems;
 
        // write the element values
        std::size_t nFieldVals = fielddata[f].size();
        data_fspace->SelectRange(data_i, nFieldVals);
        data_dset->Write(fielddata[f], data_fspace, writePL);
        data_i += nFieldVals;
    }
 
    if (order_dset)
    {
        for (int f = 0; f < nFields; ++f)
        {
            std::size_t nOrders = numModesPerDirVar[f].size();
            order_fspace->SelectRange(order_i, nOrders);
            order_dset->Write(numModesPerDirVar[f], order_fspace, writePL);
            order_i += nOrders;
        }
    }
 
    if (homy_dset)
    {
        for (int f = 0; f < nFields; ++f)
        {
            std::size_t nYIDs = homoYIDs[f].size();
            homy_fspace->SelectRange(homy_i, nYIDs);
            homy_dset->Write(homoYIDs[f], homy_fspace, writePL);
            homy_i += nYIDs;
        }
    }
 
    if (homz_dset)
    {
        for (int f = 0; f < nFields; ++f)
        {
            std::size_t nZIDs = homoZIDs[f].size();
            homz_fspace->SelectRange(homz_i, nZIDs);
            homz_dset->Write(homoZIDs[f], homz_fspace, writePL);
            homz_i += nZIDs;
        }
    }
 
    if (homs_dset)
    {
        for (int f = 0; f < nFields; ++f)
        {
            std::size_t nSIDs = homoSIDs[f].size();
            homs_fspace->SelectRange(homs_i, nSIDs);
            homs_dset->Write(homoSIDs[f], homs_fspace, writePL);
            homs_i += nSIDs;
        }
    }
 
    for (int f = nFields; f < nMaxFields; ++f)
    {
        // this MPI process is handling fewer than nMaxFields fields
        // so, since this is a collective operation
        // just rewrite the element ids and values of the last field
        ids_dset->Write(fielddefs[nFields - 1]->m_elementIDs, ids_fspace,
                        writePL);
        data_dset->Write(fielddata[nFields - 1], data_fspace, writePL);
 
        if (order_dset)
        {
            order_dset->Write(numModesPerDirVar[nFields - 1], order_fspace,
                              writePL);
        }
 
        if (homy_dset)
        {
            homy_dset->Write(homoYIDs[nFields - 1], homy_fspace, writePL);
        }
 
        if (homz_dset)
        {
            homz_dset->Write(homoZIDs[nFields - 1], homz_fspace, writePL);
        }
 
        if (homs_dset)
        {
            homs_dset->Write(homoSIDs[nFields - 1], homs_fspace, writePL);
        }
    }
 
    m_comm->GetSpaceComm()->Block();
 
    // all data has been written
    if (m_comm->GetRank() == 0)
    {
        tm1 = m_comm->Wtime();
        std::cout << " (" << tm1 - tm0 << "s, HDF5)" << std::endl;
    }
}

Member Data Documentation

◆ className

std::string Nektar::LibUtilities::FieldIOHdf5::className

static

Initial value:

=
    GetFieldIOFactory().RegisterCreatorFunction(
        "Hdf5", FieldIOHdf5::create, "HDF5-based output of field data.")

Name of class.

Definition at line 212 of file FieldIOHdf5.h.

Referenced by v_GetClassName().

◆ DATA_IDX_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::DATA_IDX_IDX = 1

static

A helper for FieldIOHdf5::v_Write. Describes the position of the data size within the indexing set.

Definition at line 196 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ ELEM_CNT_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::ELEM_CNT_IDX = 0

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of elements in the cnt array.

Definition at line 187 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ ELEM_DCMP_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::ELEM_DCMP_IDX = 0

static

A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of elements in decomposition (i.e. field definition).

Definition at line 178 of file FieldIOHdf5.h.

Referenced by v_Import(), and v_Write().

◆ FORMAT_VERSION

const unsigned int Nektar::LibUtilities::FieldIOHdf5::FORMAT_VERSION = 1

static

Version of the Nektar++ HDF5 format, which is embedded into the main NEKTAR group as an attribute.

Definition at line 176 of file FieldIOHdf5.h.

Referenced by v_Import(), and v_Write().

◆ HASH_DCMP_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HASH_DCMP_IDX = 6

static

The hash of the field definition information, which defines the name of the attribute containing the field definition itself.

Definition at line 184 of file FieldIOHdf5.h.

Referenced by v_Import(), and v_Write().

◆ HOMS_CNT_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMS_CNT_IDX = 5

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous strips in the cnt array.

Definition at line 192 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ HOMS_DCMP_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMS_DCMP_IDX = 5

static

A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of the number of strips for homogeneous simulations.

Definition at line 183 of file FieldIOHdf5.h.

Referenced by ImportFieldDef(), v_Import(), and v_Write().

◆ HOMS_IDX_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMS_IDX_IDX = 5

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous strips within the indexing set.

Definition at line 200 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ HOMY_CNT_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMY_CNT_IDX = 3

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous y-planes in the cnt array.

Definition at line 190 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ HOMY_DCMP_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMY_DCMP_IDX = 3

static

A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of the number of y-planes for homogeneous simulations.

Definition at line 181 of file FieldIOHdf5.h.

Referenced by ImportFieldDef(), v_Import(), and v_Write().

◆ HOMY_IDX_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMY_IDX_IDX = 3

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of y-planes within the indexing set.

Definition at line 198 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ HOMZ_CNT_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMZ_CNT_IDX = 4

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of homogeneous z-planes in the cnt array.

Definition at line 191 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ HOMZ_DCMP_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMZ_DCMP_IDX = 4

static

A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of the number of z-planes for homogeneous simulations.

Definition at line 182 of file FieldIOHdf5.h.

Referenced by ImportFieldDef(), v_Import(), and v_Write().

◆ HOMZ_IDX_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::HOMZ_IDX_IDX = 4

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of z-planes within the indexing set.

Definition at line 199 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ IDS_IDX_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::IDS_IDX_IDX = 0

static

A helper for FieldIOHdf5::v_Write. Describes the position of the element IDs within the indexing set.

Definition at line 195 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ MAX_CNTS

const unsigned int Nektar::LibUtilities::FieldIOHdf5::MAX_CNTS = FieldIOHdf5::HOMS_CNT_IDX + 1

static

A helper for FieldIOHdf5::v_Write. Describes the maximum number of items in the cnt array per field definition.

Definition at line 193 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ MAX_DCMPS

const unsigned int Nektar::LibUtilities::FieldIOHdf5::MAX_DCMPS = FieldIOHdf5::HASH_DCMP_IDX + 1

static

A helper for FieldIOHdf5::v_Write. Describes the maximum number of items in the decomposition per field definition.

Definition at line 185 of file FieldIOHdf5.h.

Referenced by ImportFieldDef(), v_Import(), and v_Write().

◆ MAX_IDXS

const unsigned int Nektar::LibUtilities::FieldIOHdf5::MAX_IDXS = FieldIOHdf5::HOMS_IDX_IDX + 1

static

A helper for FieldIOHdf5::v_Write. Describes the maximum number of items in the indexing set.

Definition at line 201 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ ORDER_CNT_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::ORDER_CNT_IDX = 2

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of order points in the cnt array.

Definition at line 189 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ ORDER_DCMP_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::ORDER_DCMP_IDX = 2

static

A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of elements multiplied by the dimension of the element, giving number of modes when variable polynomial order is defined.

Definition at line 180 of file FieldIOHdf5.h.

Referenced by ImportFieldDef(), v_Import(), and v_Write().

◆ ORDER_IDX_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::ORDER_IDX_IDX = 2

static

A helper for FieldIOHdf5::v_Write. Describes the position of the element order within the indexing set.

Definition at line 197 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ VAL_CNT_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::VAL_CNT_IDX = 1

static

A helper for FieldIOHdf5::v_Write. Describes the position of the number of data points in the cnt array.

Definition at line 188 of file FieldIOHdf5.h.

Referenced by v_Write().

◆ VAL_DCMP_IDX

const unsigned int Nektar::LibUtilities::FieldIOHdf5::VAL_DCMP_IDX = 1

static

A helper for FieldIOHdf5::v_Write and FieldIOHdf5::v_Import. Describes the position of the number of data points in decomposition (i.e. field definition).

Definition at line 179 of file FieldIOHdf5.h.

Referenced by v_Import(), and v_Write().

Classes

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Private Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ FieldIOHdf5()

◆ ~FieldIOHdf5()

Member Function Documentation

◆ create()

◆ ImportFieldDef()

◆ ImportHDF5FieldMetaData()

◆ v_GetClassName()

◆ v_Import()

◆ v_ImportFieldMetaData()

◆ v_Write()

Member Data Documentation

◆ className

◆ DATA_IDX_IDX

◆ ELEM_CNT_IDX

◆ ELEM_DCMP_IDX

◆ FORMAT_VERSION

◆ HASH_DCMP_IDX

◆ HOMS_CNT_IDX

◆ HOMS_DCMP_IDX

◆ HOMS_IDX_IDX

◆ HOMY_CNT_IDX

◆ HOMY_DCMP_IDX

◆ HOMY_IDX_IDX

◆ HOMZ_CNT_IDX

◆ HOMZ_DCMP_IDX

◆ HOMZ_IDX_IDX

◆ IDS_IDX_IDX

◆ MAX_CNTS

◆ MAX_DCMPS

◆ MAX_IDXS

◆ ORDER_CNT_IDX

◆ ORDER_DCMP_IDX

◆ ORDER_IDX_IDX

◆ VAL_CNT_IDX

◆ VAL_DCMP_IDX