Reference documentation for deal.II version 9.1.1
\(\newcommand{\dealcoloneq}{\mathrel{\vcenter{:}}=}\)
Public Types | Private Member Functions | Private Attributes | Friends | Related Functions | List of all members
Vector< Number > Class Template Reference

#include <deal.II/lac/vector.h>

Inheritance diagram for Vector< Number >:
[legend]

Public Types

using value_type = Number
 
using real_type = typename numbers::NumberTraits< Number >::real_type
 

Public Member Functions

Basic object handling
 Vector ()
 
 Vector (const Vector< Number > &v)
 
 Vector (Vector< Number > &&v) noexcept=default
 
template<typename OtherNumber >
 Vector (const Vector< OtherNumber > &v)
 
template<typename OtherNumber >
 Vector (const std::initializer_list< OtherNumber > &v)
 
 Vector (const PETScWrappers::VectorBase &v)
 
 Vector (const TrilinosWrappers::MPI::Vector &v)
 
 Vector (const size_type n)
 
template<typename InputIterator >
 Vector (const InputIterator first, const InputIterator last)
 
virtual ~Vector () override=default
 
void compress (::VectorOperation::values operation=::VectorOperation::unknown) const
 
virtual void reinit (const size_type N, const bool omit_zeroing_entries=false)
 
void grow_or_shrink (const size_type N)
 
void apply_givens_rotation (const std::array< Number, 3 > &csr, const size_type i, const size_type k)
 
template<typename Number2 >
void reinit (const Vector< Number2 > &V, const bool omit_zeroing_entries=false)
 
virtual void swap (Vector< Number > &v)
 
Vector< Number > & operator= (const Number s)
 
Vector< Number > & operator= (const Vector< Number > &v)
 
Vector< Number > & operator= (Vector< Number > &&v) noexcept=default
 
template<typename Number2 >
Vector< Number > & operator= (const Vector< Number2 > &v)
 
Vector< Number > & operator= (const BlockVector< Number > &v)
 
Vector< Number > & operator= (const PETScWrappers::VectorBase &v)
 
Vector< Number > & operator= (const TrilinosWrappers::MPI::Vector &v)
 
template<typename Number2 >
bool operator== (const Vector< Number2 > &v) const
 
template<typename Number2 >
bool operator!= (const Vector< Number2 > &v) const
 
Scalar products, norms and related operations
template<typename Number2 >
Number operator* (const Vector< Number2 > &V) const
 
real_type norm_sqr () const
 
Number mean_value () const
 
real_type l1_norm () const
 
real_type l2_norm () const
 
real_type lp_norm (const real_type p) const
 
real_type linfty_norm () const
 
Number add_and_dot (const Number a, const Vector< Number > &V, const Vector< Number > &W)
 
Data access
pointer data ()
 
const_pointer data () const
 
iterator begin ()
 
const_iterator begin () const
 
iterator end ()
 
const_iterator end () const
 
Number operator() (const size_type i) const
 
Number & operator() (const size_type i)
 
Number operator[] (const size_type i) const
 
Number & operator[] (const size_type i)
 
template<typename OtherNumber >
void extract_subvector_to (const std::vector< size_type > &indices, std::vector< OtherNumber > &values) const
 
template<typename ForwardIterator , typename OutputIterator >
void extract_subvector_to (ForwardIterator indices_begin, const ForwardIterator indices_end, OutputIterator values_begin) const
 
Modification of vectors
Vector< Number > & operator+= (const Vector< Number > &V)
 
Vector< Number > & operator-= (const Vector< Number > &V)
 
template<typename OtherNumber >
void add (const std::vector< size_type > &indices, const std::vector< OtherNumber > &values)
 
template<typename OtherNumber >
void add (const std::vector< size_type > &indices, const Vector< OtherNumber > &values)
 
template<typename OtherNumber >
void add (const size_type n_elements, const size_type *indices, const OtherNumber *values)
 
void add (const Number s)
 
void add (const Number a, const Vector< Number > &V, const Number b, const Vector< Number > &W)
 
void add (const Number a, const Vector< Number > &V)
 
void sadd (const Number s, const Vector< Number > &V)
 
void sadd (const Number s, const Number a, const Vector< Number > &V)
 
Vector< Number > & operator*= (const Number factor)
 
Vector< Number > & operator/= (const Number factor)
 
void scale (const Vector< Number > &scaling_factors)
 
template<typename Number2 >
void scale (const Vector< Number2 > &scaling_factors)
 
void equ (const Number a, const Vector< Number > &u)
 
template<typename Number2 >
void equ (const Number a, const Vector< Number2 > &u)
 
void ratio (const Vector< Number > &a, const Vector< Number > &b)
 
void update_ghost_values () const
 
Input and output
void print (const char *format=nullptr) const
 
void print (std::ostream &out, const unsigned int precision=3, const bool scientific=true, const bool across=true) const
 
void print (LogStream &out, const unsigned int width=6, const bool across=true) const
 
void block_write (std::ostream &out) const
 
void block_read (std::istream &in)
 
template<class Archive >
void save (Archive &ar, const unsigned int version) const
 
template<class Archive >
void load (Archive &ar, const unsigned int version)
 
Information about the object
bool in_local_range (const size_type global_index) const
 
IndexSet locally_owned_elements () const
 
size_type size () const
 
bool all_zero () const
 
bool is_non_negative () const
 
std::size_t memory_consumption () const
 
- Public Member Functions inherited from Subscriptor
 Subscriptor ()
 
 Subscriptor (const Subscriptor &)
 
 Subscriptor (Subscriptor &&) noexcept
 
virtual ~Subscriptor ()
 
Subscriptoroperator= (const Subscriptor &)
 
Subscriptoroperator= (Subscriptor &&) noexcept
 
void subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
 
void unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
 
unsigned int n_subscriptions () const
 
template<typename StreamType >
void list_subscribers (StreamType &stream) const
 
void list_subscribers () const
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 

Private Member Functions

void maybe_reset_thread_partitioner ()
 
void do_reinit (const size_type new_size, const bool omit_zeroing_entries, const bool reset_partitioner)
 

Private Attributes

AlignedVector< Number > values
 
std::shared_ptr< parallel::internal::TBBPartitioner > thread_loop_partitioner
 

Friends

template<typename Number2 >
class Vector
 

Related Functions

(Note that these are not member functions.)

template<typename Number >
void swap (LinearAlgebra::CUDAWrappers::Vector< Number > &u, LinearAlgebra::CUDAWrappers::Vector< Number > &v)
 
template<typename Number , typename MemorySpace >
void swap (LinearAlgebra::distributed::Vector< Number, MemorySpace > &u, LinearAlgebra::distributed::Vector< Number, MemorySpace > &v)
 
template<typename Number >
void swap (LinearAlgebra::ReadWriteVector< Number > &u, LinearAlgebra::ReadWriteVector< Number > &v)
 
template<typename Number >
void swap (Vector< Number > &u, Vector< Number > &v)
 

Additional Inherited Members

- Static Public Member Functions inherited from Subscriptor
static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 

Detailed Description

template<typename Number>
class Vector< Number >

A class that represents a vector of numerical elements. As for the other classes, in the Vector classes group, this class has a substantial number of member functions. These include:

In contrast to the C++ standard library class std::vector, this class intends to implement not simply an array that allows access to its elements, but indeed a vector that is a member of the mathematical concept of a "vector space" suitable for numerical computations.

Note
Instantiations for this template are provided for <float>, <double>, <std::complex<float>>, <std::complex<double>>; others can be generated in application programs (see the section on Template instantiations in the manual).
Author
Guido Kanschat, Franz-Theo Suttmeier, Wolfgang Bangerth

Definition at line 36 of file function.h.

Member Typedef Documentation

◆ value_type

template<typename Number>
using Vector< Number >::value_type = Number

Declare standard types used in all containers. These types parallel those in the C++ standard libraries vector<...> class.

Definition at line 123 of file vector.h.

◆ real_type

template<typename Number>
using Vector< Number >::real_type = typename numbers::NumberTraits<Number>::real_type

Declare a type that has holds real-valued numbers with the same precision as the template argument to this class. If the template argument of this class is a real data type, then real_type equals the template argument. If the template argument is a std::complex type then real_type equals the type underlying the complex numbers.

This alias is used to represent the return type of norms.

Definition at line 141 of file vector.h.

Constructor & Destructor Documentation

◆ Vector() [1/9]

template<typename Number>
Vector< Number >::Vector ( )

Constructor. Create a vector of dimension zero.

◆ Vector() [2/9]

template<typename Number>
Vector< Number >::Vector ( const Vector< Number > &  v)

Copy constructor. Sets the dimension to that of the given vector, and copies all elements.

We would like to make this constructor explicit, but standard containers insist on using it implicitly.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ Vector() [3/9]

template<typename Number>
Vector< Number >::Vector ( Vector< Number > &&  v)
defaultnoexcept

Move constructor. Creates a new vector by stealing the internal data of the vector v.

◆ Vector() [4/9]

template<typename Number>
template<typename OtherNumber >
Vector< Number >::Vector ( const Vector< OtherNumber > &  v)
explicit

Copy constructor taking a vector of another data type.

This constructor will fail to compile if there is no conversion path from OtherNumber to Number. You may lose accuracy when copying to a vector with data elements with less accuracy.

◆ Vector() [5/9]

template<typename Number>
template<typename OtherNumber >
Vector< Number >::Vector ( const std::initializer_list< OtherNumber > &  v)
explicit

Copy constructor taking an object of type std::initializer_list. This constructor can be used to initialize a vector using a brace-enclosed list of numbers, such as in the following example:

Vector<double> v({1,2,3});

This creates a vector of size 3, whose (double precision) elements have values 1.0, 2.0, and 3.0.

This constructor will fail to compile if there is no conversion path from OtherNumber to Number. You may lose accuracy when copying to a vector with data elements with less accuracy.

◆ Vector() [6/9]

template<typename Number>
Vector< Number >::Vector ( const PETScWrappers::VectorBase v)
explicit

Another copy constructor: copy the values from a PETSc vector class. This copy constructor is only available if PETSc was detected during configuration time.

Note that due to the communication model used in MPI, this operation can only succeed if all processes do it at the same time when v is a distributed vector: It is not possible for only one process to obtain a copy of a parallel vector while the other jobs do something else.

◆ Vector() [7/9]

template<typename Number>
Vector< Number >::Vector ( const TrilinosWrappers::MPI::Vector< Number > &  v)
explicit

Another copy constructor: copy the values from a Trilinos wrapper vector. This copy constructor is only available if Trilinos was detected during configuration time.

Note
Due to the communication model used in MPI, this operation can only succeed if all processes that have knowledge of v (i.e. those given by v.get_mpi_communicator()) do it at the same time. This means that unless you use a split MPI communicator then it is not normally possible for only one or a subset of processes to obtain a copy of a parallel vector while the other jobs do something else. In other words, calling this function is a 'collective operation' that needs to be executed by all MPI processes that jointly share v.

◆ Vector() [8/9]

template<typename Number>
Vector< Number >::Vector ( const size_type  n)
explicit

Constructor. Set dimension to n and initialize all elements with zero.

The constructor is made explicit to avoid accidents like this: v=0;. Presumably, the user wants to set every element of the vector to zero, but instead, what happens is this call: v=Vector<number>(0);, i.e. the vector is replaced by one of length zero.

◆ Vector() [9/9]

template<typename Number>
template<typename InputIterator >
Vector< Number >::Vector ( const InputIterator  first,
const InputIterator  last 
)

Initialize the vector with a given range of values pointed to by the iterators. This function is there in analogy to the std::vector class.

◆ ~Vector()

template<typename Number>
virtual Vector< Number >::~Vector ( )
overridevirtualdefault

Destructor, deallocates memory. Made virtual to allow for derived classes to behave properly.

Member Function Documentation

◆ compress()

template<typename Number>
void Vector< Number >::compress ( ::VectorOperation::values  operation = ::VectorOperation::unknown) const

This function does nothing but exists for compatibility with the parallel vector classes.

For the parallel vector wrapper class, this function compresses the underlying representation of the vector, i.e. flushes the buffers of the vector object if it has any. This function is necessary after writing into a vector element-by-element and before anything else can be done on it.

However, for the implementation of this class, it is immaterial and thus an empty function.

◆ reinit() [1/2]

template<typename Number>
virtual void Vector< Number >::reinit ( const size_type  N,
const bool  omit_zeroing_entries = false 
)
virtual

Change the dimension of the vector to N. The reserved memory for this vector remains unchanged if possible, to make things faster; this may waste some memory, so keep this in mind. However, if N==0 all memory is freed, i.e. if you want to resize the vector and release the memory not needed, you have to first call reinit(0) and then reinit(N). This cited behaviour is analogous to that of the standard library containers.

If omit_zeroing_entries is false, the vector is filled by zeros. Otherwise, the elements are left an unspecified state.

This function is virtual in order to allow for derived classes to handle memory separately.

◆ grow_or_shrink()

template<typename Number>
void Vector< Number >::grow_or_shrink ( const size_type  N)

Same as above, but will preserve the values of vector upon resizing. If we new size is bigger, we will have

\[ \mathbf V \rightarrow \left( \begin{array}{c} \mathbf V \\ \mathbf 0 \end{array} \right) \]

whereas if the desired size is smaller, then

\[ \left( \begin{array}{c} \mathbf V_1 \\ \mathbf V_2 \end{array} \right) \rightarrow \mathbf V_1 \]

◆ apply_givens_rotation()

template<typename Number>
void Vector< Number >::apply_givens_rotation ( const std::array< Number, 3 > &  csr,
const size_type  i,
const size_type  k 
)

Apply Givens rotation csr (a triplet of cosine, sine and radius, see Utilities::LinearAlgebra::givens_rotation()) to the vector in the plane spanned by the i'th and k'th unit vectors.

◆ reinit() [2/2]

template<typename Number>
template<typename Number2 >
void Vector< Number >::reinit ( const Vector< Number2 > &  V,
const bool  omit_zeroing_entries = false 
)

Change the dimension to that of the vector V. The same applies as for the other reinit function.

The elements of V are not copied, i.e. this function is the same as calling reinit (V.size(), omit_zeroing_entries).

◆ swap()

template<typename Number>
virtual void Vector< Number >::swap ( Vector< Number > &  v)
virtual

Swap the contents of this vector and the other vector v. One could do this operation with a temporary variable and copying over the data elements, but this function is significantly more efficient since it only swaps the pointers to the data of the two vectors and therefore does not need to allocate temporary storage and move data around.

This function is analogous to the swap function of all C++ standard containers. Also, there is a global function swap(u,v) that simply calls u.swap(v), again in analogy to standard functions.

This function is virtual in order to allow for derived classes to handle memory separately.

◆ operator=() [1/7]

template<typename Number>
Vector<Number>& Vector< Number >::operator= ( const Number  s)

Set all components of the vector to the given number s.

Since the semantics of assigning a scalar to a vector are not immediately clear, this operator should really only be used if you want to set the entire vector to zero. This allows the intuitive notation v=0. Assigning other values is deprecated and may be disallowed in the future.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ operator=() [2/7]

template<typename Number>
Vector<Number>& Vector< Number >::operator= ( const Vector< Number > &  v)

Copy the given vector. Resize the present vector if necessary.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ operator=() [3/7]

template<typename Number>
Vector<Number>& Vector< Number >::operator= ( Vector< Number > &&  v)
defaultnoexcept

Move the given vector. This operator replaces the present vector with the internal data of the vector v and resets v to the state it would have after being newly default-constructed.

◆ operator=() [4/7]

template<typename Number>
template<typename Number2 >
Vector<Number>& Vector< Number >::operator= ( const Vector< Number2 > &  v)

Copy the given vector. Resize the present vector if necessary.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ operator=() [5/7]

template<typename Number>
Vector<Number>& Vector< Number >::operator= ( const BlockVector< Number > &  v)

Copy operator for assigning a block vector to a regular vector.

◆ operator=() [6/7]

template<typename Number>
Vector<Number>& Vector< Number >::operator= ( const PETScWrappers::VectorBase v)

Another copy operator: copy the values from a PETSc wrapper vector class. This operator is only available if PETSc was detected during configuration time.

Note that due to the communication model used in MPI, this operation can only succeed if all processes do it at the same time when v is a distributed vector: It is not possible for only one process to obtain a copy of a parallel vector while the other jobs do something else.

◆ operator=() [7/7]

template<typename Number>
Vector<Number>& Vector< Number >::operator= ( const TrilinosWrappers::MPI::Vector< Number > &  v)

Another copy operator: copy the values from a (sequential or parallel, depending on the underlying compiler) Trilinos wrapper vector class. This operator is only available if Trilinos was detected during configuration time.

Note
Due to the communication model used in MPI, this operation can only succeed if all processes that have knowledge of v (i.e. those given by v.get_mpi_communicator()) do it at the same time. This means that unless you use a split MPI communicator then it is not normally possible for only one or a subset of processes to obtain a copy of a parallel vector while the other jobs do something else. In other words, calling this function is a 'collective operation' that needs to be executed by all MPI processes that jointly share v.

◆ operator==()

template<typename Number>
template<typename Number2 >
bool Vector< Number >::operator== ( const Vector< Number2 > &  v) const

Test for equality. This function assumes that the present vector and the one to compare with have the same size already, since comparing vectors of different sizes makes not much sense anyway.

◆ operator!=()

template<typename Number>
template<typename Number2 >
bool Vector< Number >::operator!= ( const Vector< Number2 > &  v) const

Test for inequality. This function assumes that the present vector and the one to compare with have the same size already, since comparing vectors of different sizes makes not much sense anyway.

◆ operator*()

template<typename Number>
template<typename Number2 >
Number Vector< Number >::operator* ( const Vector< Number2 > &  V) const

Return the scalar product of two vectors. The return type is the underlying type of this vector, so the return type and the accuracy with which it the result is computed depend on the order of the arguments of this vector.

For complex vectors, the scalar product is implemented as \(\left<v,w\right>=\sum_i v_i \bar{w_i}\).

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile). The algorithm uses pairwise summation with the same order of summation in every run, which gives fully repeatable results from one run to another.

◆ norm_sqr()

template<typename Number>
real_type Vector< Number >::norm_sqr ( ) const

Return the square of the \(l_2\)-norm.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile). The algorithm uses pairwise summation with the same order of summation in every run, which gives fully repeatable results from one run to another.

◆ mean_value()

template<typename Number>
Number Vector< Number >::mean_value ( ) const

Mean value of the elements of this vector.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile). The algorithm uses pairwise summation with the same order of summation in every run, which gives fully repeatable results from one run to another.

◆ l1_norm()

template<typename Number>
real_type Vector< Number >::l1_norm ( ) const

\(l_1\)-norm of the vector. The sum of the absolute values.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile). The algorithm uses pairwise summation with the same order of summation in every run, which gives fully repeatable results from one run to another.

◆ l2_norm()

template<typename Number>
real_type Vector< Number >::l2_norm ( ) const

\(l_2\)-norm of the vector. The square root of the sum of the squares of the elements.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile). The algorithm uses pairwise summation with the same order of summation in every run, which gives fully repeatable results from one run to another.

◆ lp_norm()

template<typename Number>
real_type Vector< Number >::lp_norm ( const real_type  p) const

\(l_p\)-norm of the vector. The pth root of the sum of the pth powers of the absolute values of the elements.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile). The algorithm uses pairwise summation with the same order of summation in every run, which gives fully repeatable results from one run to another.

◆ linfty_norm()

template<typename Number>
real_type Vector< Number >::linfty_norm ( ) const

Maximum absolute value of the elements.

◆ add_and_dot()

template<typename Number>
Number Vector< Number >::add_and_dot ( const Number  a,
const Vector< Number > &  V,
const Vector< Number > &  W 
)

Performs a combined operation of a vector addition and a subsequent inner product, returning the value of the inner product. In other words, the result of this function is the same as if the user called

this->add(a, V);
return_value = *this * W;

The reason this function exists is that this operation involves less memory transfer than calling the two functions separately. This method only needs to load three vectors, this, V, W, whereas calling separate methods means to load the calling vector this twice. Since most vector operations are memory transfer limited, this reduces the time by 25% (or 50% if W equals this).

For complex-valued vectors, the scalar product in the second step is implemented as \(\left<v,w\right>=\sum_i v_i \bar{w_i}\).

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile). The algorithm uses pairwise summation with the same order of summation in every run, which gives fully repeatable results from one run to another.

◆ data() [1/2]

template<typename Number>
pointer Vector< Number >::data ( )

Return a pointer to the underlying data buffer.

◆ data() [2/2]

template<typename Number>
const_pointer Vector< Number >::data ( ) const

Return a const pointer to the underlying data buffer.

◆ begin() [1/2]

template<typename Number>
iterator Vector< Number >::begin ( )

Make the Vector class a bit like the vector<> class of the C++ standard library by returning iterators to the start and end of the elements of this vector.

◆ begin() [2/2]

template<typename Number>
const_iterator Vector< Number >::begin ( ) const

Return constant iterator to the start of the vectors.

◆ end() [1/2]

template<typename Number>
iterator Vector< Number >::end ( )

Return an iterator pointing to the element past the end of the array.

◆ end() [2/2]

template<typename Number>
const_iterator Vector< Number >::end ( ) const

Return a constant iterator pointing to the element past the end of the array.

◆ operator()() [1/2]

template<typename Number>
Number Vector< Number >::operator() ( const size_type  i) const

Access the value of the ith component.

◆ operator()() [2/2]

template<typename Number>
Number& Vector< Number >::operator() ( const size_type  i)

Access the ith component as a writeable reference.

◆ operator[]() [1/2]

template<typename Number>
Number Vector< Number >::operator[] ( const size_type  i) const

Access the value of the ith component.

Exactly the same as operator().

◆ operator[]() [2/2]

template<typename Number>
Number& Vector< Number >::operator[] ( const size_type  i)

Access the ith component as a writeable reference.

Exactly the same as operator().

◆ extract_subvector_to() [1/2]

template<typename Number>
template<typename OtherNumber >
void Vector< Number >::extract_subvector_to ( const std::vector< size_type > &  indices,
std::vector< OtherNumber > &  values 
) const

Instead of getting individual elements of a vector via operator(), this function allows getting a whole set of elements at once. The indices of the elements to be read are stated in the first argument, the corresponding values are returned in the second.

If the current vector is called v, then this function is the equivalent to the code

for (unsigned int i = 0; i < indices.size(); ++i)
values[i] = v[indices[i]];
Precondition
The sizes of the indices and values arrays must be identical.

◆ extract_subvector_to() [2/2]

template<typename Number>
template<typename ForwardIterator , typename OutputIterator >
void Vector< Number >::extract_subvector_to ( ForwardIterator  indices_begin,
const ForwardIterator  indices_end,
OutputIterator  values_begin 
) const

Instead of getting individual elements of a vector via operator(), this function allows getting a whole set of elements at once. In contrast to the previous function, this function obtains the indices of the elements by dereferencing all elements of the iterator range provided by the first two arguments, and puts the vector values into memory locations obtained by dereferencing a range of iterators starting at the location pointed to by the third argument.

If the current vector is called v, then this function is the equivalent to the code

ForwardIterator indices_p = indices_begin;
OutputIterator values_p = values_begin;
while (indices_p != indices_end)
{
*values_p = v[*indices_p];
++indices_p;
++values_p;
}
Precondition
It must be possible to write into as many memory locations starting at values_begin as there are iterators between indices_begin and indices_end.

◆ operator+=()

template<typename Number>
Vector<Number>& Vector< Number >::operator+= ( const Vector< Number > &  V)

Add the given vector to the present one.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ operator-=()

template<typename Number>
Vector<Number>& Vector< Number >::operator-= ( const Vector< Number > &  V)

Subtract the given vector from the present one.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ add() [1/6]

template<typename Number>
template<typename OtherNumber >
void Vector< Number >::add ( const std::vector< size_type > &  indices,
const std::vector< OtherNumber > &  values 
)

A collective add operation: This function adds a whole set of values stored in values to the vector components specified by indices.

◆ add() [2/6]

template<typename Number>
template<typename OtherNumber >
void Vector< Number >::add ( const std::vector< size_type > &  indices,
const Vector< OtherNumber > &  values 
)

This is a second collective add operation. As a difference, this function takes a deal.II vector of values.

◆ add() [3/6]

template<typename Number>
template<typename OtherNumber >
void Vector< Number >::add ( const size_type  n_elements,
const size_type *  indices,
const OtherNumber *  values 
)

Take an address where n_elements are stored contiguously and add them into the vector. Handles all cases which are not covered by the other two add() functions above.

◆ add() [4/6]

template<typename Number>
void Vector< Number >::add ( const Number  s)

Addition of s to all components. Note that s is a scalar and not a vector.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ add() [5/6]

template<typename Number>
void Vector< Number >::add ( const Number  a,
const Vector< Number > &  V,
const Number  b,
const Vector< Number > &  W 
)

Multiple addition of scaled vectors, i.e. *this += a*V+b*W.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ add() [6/6]

template<typename Number>
void Vector< Number >::add ( const Number  a,
const Vector< Number > &  V 
)

Simple addition of a multiple of a vector, i.e. *this += a*V.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ sadd() [1/2]

template<typename Number>
void Vector< Number >::sadd ( const Number  s,
const Vector< Number > &  V 
)

Scaling and simple vector addition, i.e. *this = s*(*this)+V.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ sadd() [2/2]

template<typename Number>
void Vector< Number >::sadd ( const Number  s,
const Number  a,
const Vector< Number > &  V 
)

Scaling and simple addition, i.e. *this = s*(*this)+a*V.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ operator*=()

template<typename Number>
Vector<Number>& Vector< Number >::operator*= ( const Number  factor)

Scale each element of the vector by a constant value.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ operator/=()

template<typename Number>
Vector<Number>& Vector< Number >::operator/= ( const Number  factor)

Scale each element of the vector by the inverse of the given value.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ scale() [1/2]

template<typename Number>
void Vector< Number >::scale ( const Vector< Number > &  scaling_factors)

Scale each element of this vector by the corresponding element in the argument. This function is mostly meant to simulate multiplication (and immediate re-assignment) by a diagonal scaling matrix.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ scale() [2/2]

template<typename Number>
template<typename Number2 >
void Vector< Number >::scale ( const Vector< Number2 > &  scaling_factors)

Scale each element of this vector by the corresponding element in the argument. This function is mostly meant to simulate multiplication (and immediate re-assignment) by a diagonal scaling matrix.

◆ equ() [1/2]

template<typename Number>
void Vector< Number >::equ ( const Number  a,
const Vector< Number > &  u 
)

Assignment *this = a*u.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ equ() [2/2]

template<typename Number>
template<typename Number2 >
void Vector< Number >::equ ( const Number  a,
const Vector< Number2 > &  u 
)

Assignment *this = a*u.

◆ ratio()

template<typename Number>
void Vector< Number >::ratio ( const Vector< Number > &  a,
const Vector< Number > &  b 
)

Compute the elementwise ratio of the two given vectors, that is let this[i] = a[i]/b[i]. This is useful for example if you want to compute the cellwise ratio of true to estimated error.

This vector is appropriately scaled to hold the result.

If any of the b[i] is zero, the result is undefined. No attempt is made to catch such situations.

Note
If deal.II is configured with threads, this operation will run multi-threaded by splitting the work into smaller chunks (assuming there is enough work to make this worthwhile).

◆ update_ghost_values()

template<typename Number>
void Vector< Number >::update_ghost_values ( ) const

This function does nothing but exists for compatibility with the parallel vector classes (e.g., LinearAlgebra::distributed::Vector class).

◆ print() [1/3]

template<typename Number>
void Vector< Number >::print ( const char *  format = nullptr) const

Output of vector in user-defined format. For complex-valued vectors, the format should include specifiers for both the real and imaginary parts.

This function is deprecated.

◆ print() [2/3]

template<typename Number>
void Vector< Number >::print ( std::ostream &  out,
const unsigned int  precision = 3,
const bool  scientific = true,
const bool  across = true 
) const

Print to a stream. precision denotes the desired precision with which values shall be printed, scientific whether scientific notation shall be used. If across is true then the vector is printed in a line, while if false then the elements are printed on a separate line each.

◆ print() [3/3]

template<typename Number>
void Vector< Number >::print ( LogStream out,
const unsigned int  width = 6,
const bool  across = true 
) const

Print to a LogStream. width is used as argument to the std::setw manipulator, if printing across. If across is true then the vector is printed in a line, while if false then the elements are printed on a separate line each.

This function is deprecated.

◆ block_write()

template<typename Number>
void Vector< Number >::block_write ( std::ostream &  out) const

Write the vector en bloc to a file. This is done in a binary mode, so the output is neither readable by humans nor (probably) by other computers using a different operating system or number format.

◆ block_read()

template<typename Number>
void Vector< Number >::block_read ( std::istream &  in)

Read a vector en block from a file. This is done using the inverse operations to the above function, so it is reasonably fast because the bitstream is not interpreted.

The vector is resized if necessary.

A primitive form of error checking is performed which will recognize the bluntest attempts to interpret some data as a vector stored bitwise to a file, but not more.

◆ save()

template<typename Number>
template<class Archive >
void Vector< Number >::save ( Archive &  ar,
const unsigned int  version 
) const

Write the data of this object to a stream for the purpose of serialization.

◆ load()

template<typename Number>
template<class Archive >
void Vector< Number >::load ( Archive &  ar,
const unsigned int  version 
)

Read the data of this object from a stream for the purpose of serialization.

◆ in_local_range()

template<typename Number>
bool Vector< Number >::in_local_range ( const size_type  global_index) const

Return true if the given global index is in the local range of this processor. Since this is not a distributed vector the method always returns true.

◆ locally_owned_elements()

template<typename Number>
IndexSet Vector< Number >::locally_owned_elements ( ) const

Return an index set that describes which elements of this vector are owned by the current processor. Note that this index set does not include elements this vector may store locally as ghost elements but that are in fact owned by another processor. As a consequence, the index sets returned on different processors if this is a distributed vector will form disjoint sets that add up to the complete index set. Obviously, if a vector is created on only one processor, then the result would satisfy

vec.locally_owned_elements() == complete_index_set (vec.size())

Since the current data type does not support parallel data storage across different processors, the returned index set is the complete index set.

◆ size()

template<typename Number>
size_type Vector< Number >::size ( ) const

Return dimension of the vector.

◆ all_zero()

template<typename Number>
bool Vector< Number >::all_zero ( ) const

Return whether the vector contains only elements with value zero. This function is mainly for internal consistency checks and should seldom be used when not in debug mode since it uses quite some time.

◆ is_non_negative()

template<typename Number>
bool Vector< Number >::is_non_negative ( ) const

Return true if the vector has no negative entries, i.e. all entries are zero or positive. This function is used, for example, to check whether refinement indicators are really all positive (or zero).

The function obviously only makes sense if the template argument of this class is a real type. If it is a complex type, then an exception is thrown.

◆ memory_consumption()

template<typename Number>
std::size_t Vector< Number >::memory_consumption ( ) const

Determine an estimate for the memory consumption (in bytes) of this object.

◆ maybe_reset_thread_partitioner()

template<typename Number>
void Vector< Number >::maybe_reset_thread_partitioner ( )
private

Convenience function used at the end of initialization or reinitialization. Resets (if necessary) the loop partitioner to the correct state, based on its current state and the length of the vector.

◆ do_reinit()

template<typename Number>
void Vector< Number >::do_reinit ( const size_type  new_size,
const bool  omit_zeroing_entries,
const bool  reset_partitioner 
)
private

Actual implementation of the reinit functions.

Friends And Related Function Documentation

◆ Vector

template<typename Number>
template<typename Number2 >
friend class Vector
friend

Make all other vector types friends.

Typedef for the vector type used

Typedef for the vector type used.

Implementation of a parallel vector class. The design of this class is similar to the standard Vector class in deal.II, with the exception that storage is distributed with MPI.

The vector is designed for the following scheme of parallel partitioning:

  • The indices held by individual processes (locally owned part) in the MPI parallelization form a contiguous range [my_first_index,my_last_index).
  • Ghost indices residing on arbitrary positions of other processors are allowed. It is in general more efficient if ghost indices are clustered, since they are stored as a set of intervals. The communication pattern of the ghost indices is determined when calling the function reinit (locally_owned, ghost_indices, communicator), and retained until the partitioning is changed. This allows for efficient parallel communication of indices. In particular, it stores the communication pattern, rather than having to compute it again for every communication. For more information on ghost vectors, see also the glossary entry on vectors with ghost elements.
  • Besides the usual global access operator() it is also possible to access vector entries in the local index space with the function local_element(). Locally owned indices are placed first, [0, local_size()), and then all ghost indices follow after them contiguously, [local_size(), local_size()+n_ghost_entries()).

Functions related to parallel functionality:

  • The function compress() goes through the data associated with ghost indices and communicates it to the owner process, which can then add it to the correct position. This can be used e.g. after having run an assembly routine involving ghosts that fill this vector. Note that the insert mode of compress() does not set the elements included in ghost entries but simply discards them, assuming that the owning processor has set them to the desired value already (See also the glossary entry on compress).
  • The update_ghost_values() function imports the data from the owning processor to the ghost indices in order to provide read access to the data associated with ghosts.
  • It is possible to split the above functions into two phases, where the first initiates the communication and the second one finishes it. These functions can be used to overlap communication with computations in other parts of the code.
  • Of course, reduction operations (like norms) make use of collective all-to-all MPI communications.

This vector can take two different states with respect to ghost elements:

  • After creation and whenever zero_out_ghosts() is called (or operator= (0.)), the vector does only allow writing into ghost elements but not reading from ghost elements.
  • After a call to update_ghost_values(), the vector does not allow writing into ghost elements but only reading from them. This is to avoid undesired ghost data artifacts when calling compress() after modifying some vector entries. The current status of the ghost entries (read mode or write mode) can be queried by the method has_ghost_elements(), which returns true exactly when ghost elements have been updated and false otherwise, irrespective of the actual number of ghost entries in the vector layout (for that information, use n_ghost_entries() instead).

This vector uses the facilities of the class Vector<Number> for implementing the operations on the local range of the vector. In particular, it also inherits thread parallelism that splits most vector-vector operations into smaller chunks if the program uses multiple threads. This may or may not be desired when working also with MPI.

Limitations regarding the vector size

This vector class is based on two different number types for indexing. The so-called global index type encodes the overall size of the vector. Its type is types::global_dof_index. The largest possible value is 2^32-1 or approximately 4 billion in case 64 bit integers are disabled at configuration of deal.II (default case) or 2^64-1 or approximately 10^19 if 64 bit integers are enabled (see the glossary entry on When to use types::global_dof_index instead of unsigned int for further information).

The second relevant index type is the local index used within one MPI rank. As opposed to the global index, the implementation assumes 32-bit unsigned integers unconditionally. In other words, to actually use a vector with more than four billion entries, you need to use MPI with more than one rank (which in general is a safe assumption since four billion entries consume at least 16 GB of memory for floats or 32 GB of memory for doubles) and enable 64-bit indices. If more than 4 billion local elements are present, the implementation tries to detect that, which triggers an exception and aborts the code. Note, however, that the detection of overflow is tricky and the detection mechanism might fail in some circumstances. Therefore, it is strongly recommended to not rely on this class to automatically detect the unsupported case.

Author
Katharina Kormann, Martin Kronbichler, 2010, 2011
Deprecated:
Use LinearAlgebra::distributed::Vector instead.

Definition at line 1043 of file vector.h.

◆ swap() [1/3]

template<typename Number >
void swap ( LinearAlgebra::CUDAWrappers::Vector< Number > &  u,
LinearAlgebra::CUDAWrappers::Vector< Number > &  v 
)
related

Global function swap which overloads the default implementation of the C++ standard library which uses a temporary object. The function simply exchanges the data of the two vectors.

Author
Daniel Arndt, 2018

Definition at line 360 of file cuda_vector.h.

◆ swap() [2/3]

template<typename Number , typename MemorySpace >
void swap ( LinearAlgebra::distributed::Vector< Number, MemorySpace > &  u,
LinearAlgebra::distributed::Vector< Number, MemorySpace > &  v 
)
related

Global function swap which overloads the default implementation of the C++ standard library which uses a temporary object. The function simply exchanges the data of the two vectors.

Author
Katharina Kormann, Martin Kronbichler, 2011

Definition at line 1845 of file la_parallel_vector.h.

◆ swap() [3/3]

template<typename Number >
void swap ( LinearAlgebra::ReadWriteVector< Number > &  u,
LinearAlgebra::ReadWriteVector< Number > &  v 
)
related

Global function swap which overloads the default implementation of the C++ standard library which uses a temporary object. The function simply exchanges the data of the two vectors.

Definition at line 1046 of file read_write_vector.h.

Member Data Documentation

◆ values

template<typename Number>
AlignedVector<Number> Vector< Number >::values
private

Array of elements owned by this vector.

Definition at line 1014 of file vector.h.

◆ thread_loop_partitioner

template<typename Number>
std::shared_ptr<parallel::internal::TBBPartitioner> Vector< Number >::thread_loop_partitioner
mutableprivate

For parallel loops with TBB, this member variable stores the affinity information of loops.

Definition at line 1037 of file vector.h.


The documentation for this class was generated from the following files: