Nektar::StdRegions::VarCoeffEntry Struct Reference

Representation of a variable coefficient. More...

#include <StdRegions.hpp>

Public Member Functions
	VarCoeffEntry ()=default
	Default constructor.
	VarCoeffEntry (const Array< OneD, const NekDouble > &input)
	Copy an array of values into this entry.
const NekDouble &	operator[] (std::size_t idx) const
	Access an entry idx within m_coeffs.
void	operator= (const Array< OneD, const NekDouble > &rhs)
	Assignment operator given an array rhs.
const Array< OneD, const NekDouble > &	GetValue () const
	Returns a const reference to the coefficients.
std::size_t	GetHash () const
	Returns the hash of this entry.
VarCoeffEntry	restrict (size_t offset, size_t size) const

Protected Member Functions
void	ComputeHash ()
	Computes the hash of this entry using hash_range.

Protected Attributes
std::size_t	m_hash = 0
	Hash of the entries inside m_coeffs.
Array< OneD, NekDouble >	m_coeffs
	Storage for the variable coefficient entries.

Detailed Description

Representation of a variable coefficient.

Variable coefficients are entries stored inside a VarCoeffMap which are defined at each quadrature/solution point within an element. This class wraps that concept, storing the values in m_coeffs, but also stores alongside this a hash of the data in m_hash. This is then used within MultiRegions::GlobalMatrixKey to efficiently distinguish between matrix keys that have variable coefficients defined, but whose entries are different.

For that reason the entries here are deliberately protected by const references; i.e. the entries inside of m_coeffs should not be modified in-place, but a new array copied in so that the hash can be recalculated.

Definition at line 321 of file StdRegions.hpp.

Constructor & Destructor Documentation

VarCoeffEntry() [1/2]

Nektar::StdRegions::VarCoeffEntry::VarCoeffEntry ( )

default

Default constructor.

VarCoeffEntry() [2/2]

Nektar::StdRegions::VarCoeffEntry::VarCoeffEntry ( const Array< OneD, const NekDouble > &  input )

inline

Copy an array of values into this entry.

Upon copy into m_coeffs, compute the hash of this entry using ComputeHash.

Parameters

input

Variable coefficients to be defined at each solution point.

Definition at line 335 of file StdRegions.hpp.

                                                             : m_coeffs(input)
    {
        ComputeHash();
    }

References ComputeHash().

Member Function Documentation

ComputeHash()

void Nektar::StdRegions::VarCoeffEntry::ComputeHash ( )

inlineprotected

Computes the hash of this entry using hash_range.

Definition at line 414 of file StdRegions.hpp.

    {
        if (m_coeffs.size() == 0)
        {
            m_hash = 0;
            return;
        }
 
        m_hash = hash_range(m_coeffs.begin(), m_coeffs.end());
    }

References Nektar::hash_range(), m_coeffs, and m_hash.

Referenced by operator=(), and VarCoeffEntry().

GetHash()

std::size_t Nektar::StdRegions::VarCoeffEntry::GetHash ( ) const

inline

Returns the hash of this entry.

Definition at line 376 of file StdRegions.hpp.

    {
        return m_hash;
    }

References m_hash.

GetValue()

const Array< OneD, const NekDouble > & Nektar::StdRegions::VarCoeffEntry::GetValue ( ) const

inline

Returns a const reference to the coefficients.

Definition at line 368 of file StdRegions.hpp.

    {
        return m_coeffs;
    }

References m_coeffs.

Referenced by pybind11::detail::type_caster< VarCoeffEntry >::cast().

operator=()

void Nektar::StdRegions::VarCoeffEntry::operator= ( const Array< OneD, const NekDouble > &  rhs )

inline

Assignment operator given an array rhs.

Upon copy into m_coeffs, compute the hash of this entry using ComputeHash.

Parameters

rhs	Variable coefficients to be defined at each solution point.

Definition at line 359 of file StdRegions.hpp.

    {
        m_coeffs = rhs;
        ComputeHash();
    }

References ComputeHash(), and m_coeffs.

operator[]()

const NekDouble & Nektar::StdRegions::VarCoeffEntry::operator[] ( std::size_t  idx ) const

inline

Access an entry idx within m_coeffs.

Parameters

idx	Index of the entry to access.

Definition at line 345 of file StdRegions.hpp.

    {
        return m_coeffs[idx];
    }

References m_coeffs.

restrict()

VarCoeffEntry Nektar::StdRegions::VarCoeffEntry::restrict ( size_t  offset, size_t  size  ) const

inline

Definition at line 391 of file StdRegions.hpp.

    {
        VarCoeffEntry tmp;
 
        // This avoids copy of Array
        tmp.m_coeffs = Array<OneD, NekDouble>(size, m_coeffs + offset);
 
        // The logic is that since we are using a 'window' into the original
        // data we should preserve the original hash of that data.
        // Giving just m_hash will result in the same hash for all collections.
        // This is sufficient, because if we only need to update once every time
        // step. For possible future changes, we could combine it with the
        // offset and size to make it different enough to the original hash, if
        // necessary.
        tmp.m_hash = m_hash;
 
        return tmp;
    }

References m_coeffs, and m_hash.

Member Data Documentation

m_coeffs

Array<OneD, NekDouble> Nektar::StdRegions::VarCoeffEntry::m_coeffs

protected

Storage for the variable coefficient entries.

Definition at line 429 of file StdRegions.hpp.

Referenced by ComputeHash(), GetValue(), operator=(), operator[](), and restrict().

m_hash

std::size_t Nektar::StdRegions::VarCoeffEntry::m_hash = 0

protected

Hash of the entries inside m_coeffs.

Definition at line 426 of file StdRegions.hpp.

Referenced by ComputeHash(), GetHash(), and restrict().