Reference documentation for deal.II version Git 9297d75edf 20201126 18:52:14 +0100

Namespaces  
CUDA  
LinearAlgebra  
MPI  
System  
Trilinos  
Classes  
class  MutableBind 
Functions  
IndexSet  create_evenly_distributed_partitioning (const unsigned int my_partition_id, const unsigned int n_partitions, const IndexSet::size_type total_size) 
template<typename ReturnType , class... FunctionArgs>  
MutableBind< ReturnType, FunctionArgs... >  mutable_bind (ReturnType(*function)(FunctionArgs...), typename identity< FunctionArgs >::type &&... arguments) 
template<typename ReturnType , class... FunctionArgs>  
MutableBind< ReturnType, FunctionArgs... >  mutable_bind (std::function< ReturnType(FunctionArgs...)>, typename identity< FunctionArgs >::type &&... arguments) 
template<typename ReturnType , class... FunctionArgs>  
MutableBind< ReturnType, FunctionArgs... >  mutable_bind (ReturnType(*function)(FunctionArgs...)) 
template<typename ReturnType , class... FunctionArgs>  
MutableBind< ReturnType, FunctionArgs... >  mutable_bind (std::function< ReturnType(FunctionArgs...)>) 
std::string  dealii_version_string () 
template<int dim, typename Number >  
std::vector< std::array< std::uint64_t, dim > >  inverse_Hilbert_space_filling_curve (const std::vector< Point< dim, Number >> &points, const int bits_per_dim=64) 
template<int dim>  
std::vector< std::array< std::uint64_t, dim > >  inverse_Hilbert_space_filling_curve (const std::vector< std::array< std::uint64_t, dim >> &points, const int bits_per_dim=64) 
template<int dim>  
std::uint64_t  pack_integers (const std::array< std::uint64_t, dim > &index, const int bits_per_dim) 
std::string  compress (const std::string &input) 
std::string  decompress (const std::string &compressed_input) 
std::string  encode_base64 (const std::vector< unsigned char > &binary_input) 
std::vector< unsigned char >  decode_base64 (const std::string &base64_input) 
std::string  int_to_string (const unsigned int value, const unsigned int digits=numbers::invalid_unsigned_int) 
template<typename number >  
std::string  to_string (const number value, const unsigned int digits=numbers::invalid_unsigned_int) 
unsigned int  needed_digits (const unsigned int max_number) 
template<typename Number >  
Number  truncate_to_n_digits (const Number number, const unsigned int n_digits) 
int  string_to_int (const std::string &s) 
std::string  dim_string (const int dim, const int spacedim) 
std::vector< int >  string_to_int (const std::vector< std::string > &s) 
double  string_to_double (const std::string &s) 
std::vector< double >  string_to_double (const std::vector< std::string > &s) 
std::vector< std::string >  split_string_list (const std::string &s, const std::string &delimiter=",") 
std::vector< std::string >  split_string_list (const std::string &s, const char delimiter) 
std::vector< std::string >  break_text_into_lines (const std::string &original_text, const unsigned int width, const char delimiter=' ') 
bool  match_at_string_start (const std::string &name, const std::string &pattern) 
std::pair< int, unsigned int >  get_integer_at_position (const std::string &name, const unsigned int position) 
std::string  replace_in_string (const std::string &input, const std::string &from, const std::string &to) 
std::string  trim (const std::string &input) 
double  generate_normal_random_number (const double a, const double sigma) 
template<class T >  
std::string  type_to_string (const T &t) 
template<int N, typename T >  
T  fixed_power (const T t) 
template<typename T >  
constexpr T  pow (const T base, const int iexp) 
template<typename Iterator , typename T >  
Iterator  lower_bound (Iterator first, Iterator last, const T &val) 
template<typename Iterator , typename T , typename Comp >  
Iterator  lower_bound (Iterator first, Iterator last, const T &val, const Comp comp) 
template<typename Integer >  
std::vector< Integer >  reverse_permutation (const std::vector< Integer > &permutation) 
template<typename Integer >  
std::vector< Integer >  invert_permutation (const std::vector< Integer > &permutation) 
template<typename T >  
size_t  pack (const T &object, std::vector< char > &dest_buffer, const bool allow_compression=true) 
template<typename T >  
std::vector< char >  pack (const T &object, const bool allow_compression=true) 
template<typename T >  
T  unpack (const std::vector< char > &buffer, const bool allow_compression=true) 
template<typename T >  
T  unpack (const std::vector< char >::const_iterator &cbegin, const std::vector< char >::const_iterator &cend, const bool allow_compression=true) 
template<typename T , int N>  
void  unpack (const std::vector< char > &buffer, T(&unpacked_object)[N], const bool allow_compression=true) 
template<typename T , int N>  
void  unpack (const std::vector< char >::const_iterator &cbegin, const std::vector< char >::const_iterator &cend, T(&unpacked_object)[N], const bool allow_compression=true) 
template<typename To , typename From >  
std::unique_ptr< To >  dynamic_unique_cast (std::unique_ptr< From > &&p) 
static ::ExceptionBase &  ExcInvalidNumber2StringConversersion (unsigned int arg1, unsigned int arg2) 
static ::ExceptionBase &  ExcInvalidNumber (unsigned int arg1) 
static ::ExceptionBase &  ExcCantConvertString (std::string arg1) 
A namespace for utility functions that are not particularly specific to finite element computing or numerical programs, but nevertheless are needed in various contexts when writing applications.
IndexSet Utilities::create_evenly_distributed_partitioning  (  const unsigned int  my_partition_id, 
const unsigned int  n_partitions,  
const IndexSet::size_type  total_size  
) 
Given the total number of elements total_size
, create an evenly distributed 1:1 partitioning of the elements for across n_partitions
. The local sizes will be equal to the total_size
divided by the number of partitions plus the remainder being divided amongst the first processes. Each process will store a contiguous subset of indices, and the index set on process p+1 starts at the index one larger than the last one stored on process p. For example, a total_size
of 11 with 3 processes will result in the IndexSets { [0,4), [4,8), [8,11)] }, and this function will return the my_partition_id
's IndexSet.
MutableBind<ReturnType, FunctionArgs...> Utilities::mutable_bind  (  ReturnType(*)(FunctionArgs...)  function, 
typename identity< FunctionArgs >::type &&...  arguments  
) 
Create a MutableBind object from a function pointer and a list of arguments.
An example usage is given by:
MutableBind<ReturnType, FunctionArgs...> Utilities::mutable_bind  (  std::function< ReturnType(FunctionArgs...)>  , 
typename identity< FunctionArgs >::type &&...  arguments  
) 
Same as above, using a std::function object.
MutableBind<ReturnType, FunctionArgs...> Utilities::mutable_bind  (  ReturnType(*)(FunctionArgs...)  function  ) 
Create a MutableBind object from a function pointer, with uninitialized arguments.
Notice that if you do not call one of the MutableBind::set_arguments() methods, or the MutableBind::parse_arguments() function on the returned object, then the arguments passed to the function object will be initialized with the values coming from each of the arguments' default constructors.
MutableBind<ReturnType, FunctionArgs...> Utilities::mutable_bind  (  std::function< ReturnType(FunctionArgs...)>  ) 
Same as above, using a std::function object.
std::string Utilities::dealii_version_string  (  ) 
Return a string of the form "deal.II version x.y.z" where "x.y.z" identifies the version of deal.II you are using. This information is also provided by the DEAL_II_PACKAGE_NAME and DEAL_II_PACKAGE_VERSION preprocessor variables.
Definition at line 97 of file utilities.cc.
std::vector< std::array< std::uint64_t, dim > > Utilities::inverse_Hilbert_space_filling_curve  (  const std::vector< Point< dim, Number >> &  points, 
const int  bits_per_dim = 64 

) 
Assign to each point in points
an index using the Hilbert space filling curve. To that end, a bounding box for points
will be determined, based on which their integer coordinates are calculated. The linear index is given as a dimcollection of bits, from high to low. This is done in order to keep the maximum resolution in terms of bit depth along each axis. Note that this diminteger index can still be easily used for sorting and ordering, for example using the lexicographic ordering of tuples of integers.
The depth of the Hilbert curve (i.e. the number of bits per dimension) by default is equal to 64
.
Definition at line 148 of file utilities.cc.
std::vector< std::array< std::uint64_t, dim > > Utilities::inverse_Hilbert_space_filling_curve  (  const std::vector< std::array< std::uint64_t, dim >> &  points, 
const int  bits_per_dim = 64 

) 
Same as above, but for points in integer coordinates.
Definition at line 257 of file utilities.cc.
std::uint64_t Utilities::pack_integers  (  const std::array< std::uint64_t, dim > &  index, 
const int  bits_per_dim  
) 
Pack the least significant bits_per_dim
bits from each element of index
(starting from last) into a single unsigned integer. The last element of index
will be used to set the first bits_per_dim
bits in the resulting integer, the second to last element is used to set the next bits_per_dim
bits, etc.. To fit all the data into the output, the following should hold bits_per_dim * dim <= 64
.
The function is useful in debugging and visualization of indices returned by inverse_Hilbert_space_filling_curve().
std::lexicographical_compare()
. Definition at line 369 of file utilities.cc.
std::string Utilities::compress  (  const std::string &  input  ) 
If the library is configured with ZLIB, then this function compresses the input string and returns a nonzero terminated string containing the compressed input.
If the library was not configured with ZLIB enabled, the returned string is identical to the input string.
[in]  input  The string to compress 
Definition at line 392 of file utilities.cc.
std::string Utilities::decompress  (  const std::string &  compressed_input  ) 
If the library is configured with ZLIB, then this function assumes that the input string has been compressed using the compress() function, and returns the original decompressed string.
If the library was not configured with ZLIB enabled, the returned string is identical to the input string.
[in]  compressed_input  A compressed string, as returned by the function compress() 
Definition at line 415 of file utilities.cc.
std::string Utilities::encode_base64  (  const std::vector< unsigned char > &  binary_input  ) 
Encodes the binary input as a base64 string.
Base64 is a group of binarytotext encoding schemes that represent binary data in an ASCII string format by translating it into a radix64 representation. Base64 is designed to carry data stored in binary formats across channels that only reliably support text content. It is used also to store binary formats in a machine independent way.
binary_input  A vector of characters, representing your input as binary data. 
Definition at line 437 of file utilities.cc.
std::vector< unsigned char > Utilities::decode_base64  (  const std::string &  base64_input  ) 
Decodes a base64 string into a binary output.
This is the inverse of the encode_base64() function above.
base64_input  A string that contains the input in base64 format. 
Definition at line 450 of file utilities.cc.
std::string Utilities::int_to_string  (  const unsigned int  value, 
const unsigned int  digits = numbers::invalid_unsigned_int 

) 
Convert a number value
to a string, with as many digits as given to fill with leading zeros.
If the second parameter is left at its default value, the number is not padded with leading zeros. The result is then the same as if the standard C++ std::to_string
(or the older C function itoa()
) had been called.
This function takes an unsigned int
as argument. As a consequence, if you call it with a signed int
(which is of course the same type as int
), the argument is implicitly converted to unsigned integers and negative numbers may not be printed as you had hoped. Similarly, if you call the function with a long int
, the printed result might show the effects of an overflow upon conversion to unsigned int
.
Utilities::to_string()
instead. In its current implementation the function simply calls to_string<unsigned int>()
. Definition at line 474 of file utilities.cc.
std::string Utilities::to_string  (  const number  value, 
const unsigned int  digits = numbers::invalid_unsigned_int 

) 
Convert a number value
to a string, with digits
characters. The string is padded with leading zeros, after a possible minus sign. Therefore the total number of padding zeros is digits
minus any signs, decimal points and digits of value
.
If the second parameter is left at its default value, the number is not padded with leading zeros. The result is then the same as if the C++ function std::to_string()
had been called (for integral types), or if boost::lexical_cast()
had been called (for all other types).
Definition at line 483 of file utilities.cc.
Determine how many digits are needed to represent numbers at most as large as the given number.
Definition at line 569 of file utilities.cc.
Number Utilities::truncate_to_n_digits  (  const Number  number, 
const unsigned int  n_digits  
) 
This function allows to cut off a floating point number number
after n_digits
of accuracy, i.e., after n_digits
decimal places in scientific floating point notation. When interpreted as rounding operation, this function reduces the absolute value of a floating point number and always rounds towards zero, since decimal places are simply cut off.
Definition at line 582 of file utilities.cc.
int Utilities::string_to_int  (  const std::string &  s  ) 
Given a string, convert it to an integer. Throw an assertion if that is not possible.
Definition at line 609 of file utilities.cc.
Return a string describing the dimensions of the object. Often, functions in the deal.II library as well as in user codes need to define a string containing the template dimensions of some objects defined using two template parameters: dim (the topological dimension of the object) and spacedim (the dimension of the embedding Euclidean space). Since in all deal.II classes, by default spacedim is equal to dimension, the above string is usually contracted to "<dim>", instead of "<dim,spacedim>". This function returns a string containing "dim" if dim is equal to spacedim, otherwise it returns "dim,spacedim".
Definition at line 559 of file utilities.cc.
std::vector< int > Utilities::string_to_int  (  const std::vector< std::string > &  s  ) 
Given a list of strings, convert it to a list of integers. Throw an assertion if that is not possible.
Definition at line 646 of file utilities.cc.
double Utilities::string_to_double  (  const std::string &  s  ) 
Given a string, convert it to an double. Throw an assertion if that is not possible.
Definition at line 657 of file utilities.cc.
std::vector< double > Utilities::string_to_double  (  const std::vector< std::string > &  s  ) 
Given a list of strings, convert it to a list of doubles. Throw an assertion if that is not possible.
Definition at line 694 of file utilities.cc.
std::vector< std::string > Utilities::split_string_list  (  const std::string &  s, 
const std::string &  delimiter = "," 

) 
Given a string that contains text separated by a delimiter
, split it into its components; for each component, remove leading and trailing spaces. The default value of the delimiter is a comma, so that the function splits comma separated lists of strings.
To make data input from tables simpler, if the input string ends in a delimiter (possibly followed by an arbitrary amount of whitespace), then this last delimiter is ignored. For example,
yields the same 3element list of output {"abc","def","ghi"}
as you would get if the input had been
or
As a consequence of this rule, a call like
yields a oneelement list. Because of the trimming of whitespace, the single element is the empty string.
This function can digest the case that the delimiter is a space. In this case, it returns all words in the string. Combined with the rules above, this implies that
yields again the 3element list of output {"abc","def","ghi"}
from above despite the presence of space at the end of the string. Furthermore,
yields an empty list regardless of the number of spaces in the string.
Definition at line 705 of file utilities.cc.
std::vector< std::string > Utilities::split_string_list  (  const std::string &  s, 
const char  delimiter  
) 
Specialization of split_string_list() for the case where the delimiter is a single char.
Definition at line 750 of file utilities.cc.
std::vector< std::string > Utilities::break_text_into_lines  (  const std::string &  original_text, 
const unsigned int  width,  
const char  delimiter = ' ' 

) 
Take a text, usually a documentation or something, and try to break it into individual lines of text at most width
characters wide, by breaking at positions marked by delimiter
in the text. If this is not possible, return the shortest lines that are longer than width
. The default value of the delimiter is a space character. If original_text contains newline characters (
), the string is split at these locations, too.
Definition at line 759 of file utilities.cc.
bool Utilities::match_at_string_start  (  const std::string &  name, 
const std::string &  pattern  
) 
Return true if the given pattern string appears in the first position of the string.
Definition at line 839 of file utilities.cc.
std::pair< int, unsigned int > Utilities::get_integer_at_position  (  const std::string &  name, 
const unsigned int  position  
) 
Read a (signed) integer starting at the position in name
indicated by the second argument, and return this integer as a pair together with how many characters it takes up in the string.
If no integer can be read at the indicated position, return (1,numbers::invalid_unsigned_int)
Definition at line 854 of file utilities.cc.
std::string Utilities::replace_in_string  (  const std::string &  input, 
const std::string &  from,  
const std::string &  to  
) 
Return a string with all occurrences of from
in input
replaced by to
.
Definition at line 513 of file utilities.cc.
std::string Utilities::trim  (  const std::string &  input  ) 
Return a string with all standard whitespace characters (including '\t
', '\n
', and '\r
') at the beginning and end of input
removed.
Definition at line 532 of file utilities.cc.
Generate a random number from a normalized Gaussian probability distribution centered around a
and with standard deviation sigma
. The returned number will be different every time the function is called.
This function is reentrant, i.e., it can safely be called from multiple threads at the same time. In addition, each thread will get the same sequence of numbers every time. On the other hand, if you run Threads::Task objects via the Threading Building Blocks, then tasks will be assigned to mostly random threads, and may get a different sequence of random numbers in different runs of the program, since a previous task may already have consumed the first few random numbers generated for the thread you're on. If this is a problem, you need to create your own random number generator objects every time you want to start from a defined point.
rand()
, you can call srand()
to "seed" the random number generator to get different sequences of random numbers every time a program is called. However, this function does not allow seeding the random number generator. If you need this, as above, use one of the C++ or BOOST facilities. Definition at line 896 of file utilities.cc.

inline 
Return a string description of the type of the variable t
.
In general, C++ uses mangled names to identify types. This function uses boost::core::demangle to return a human readable string describing the type of the variable passed as argument.
Definition at line 1066 of file utilities.h.

inline 
Calculate a fixed power, provided as a template argument, of a number.
This function provides an efficient way to calculate things like t^N
where N
is a known number at compile time.
Use this function as in fixed_power<dim> (n)
.
Definition at line 1045 of file utilities.h.
constexpr T Utilities::pow  (  const T  base, 
const int  iexp  
) 
A replacement for std::pow
that allows compiletime calculations for constant expression arguments. The base
must be an integer type and the exponent iexp
must not be negative.
Definition at line 461 of file utilities.h.

inline 
Optimized replacement for std::lower_bound
for searching within the range of column indices. Slashes execution time by approximately one half for the present application, partly because the binary search is replaced by a linear search for small loop lengths.
Another reason for this function is rather obscure: when using the GCC libstdc++ function std::lower_bound, complexity is O(log(N)) as required. However, when using the debug version of the GCC libstdc++ as we do when running the testsuite, then std::lower_bound tests whether the sequence is in fact partitioned with respect to the pivot 'value' (i.e. in essence that the sequence is sorted as required for binary search to work). However, verifying this means that the complexity of std::lower_bound jumps to O(N); we call this function O(N) times below, making the overall complexity O(N**2). The consequence is that a few tests with big meshes completely run off the wall time limit for tests and fail with the libstdc++ debug mode
This function simply makes the assumption that the sequence is sorted, and we simply don't do the additional check.
Definition at line 1075 of file utilities.h.

inline 
The same function as above, but taking an argument that is used to compare individual elements of the sequence of objects pointed to by the iterators.
Definition at line 1084 of file utilities.h.
std::vector< Integer > Utilities::reverse_permutation  (  const std::vector< Integer > &  permutation  ) 
Given a permutation vector (i.e. a vector \(p_0\ldots p_{N1}\) where each \(p_i\in [0,N)\) and \(p_i\neq p_j\) for \(i\neq j\)), produce the reverse permutation \(q_i=N1p_i\).
Definition at line 1404 of file utilities.h.
std::vector< Integer > Utilities::invert_permutation  (  const std::vector< Integer > &  permutation  ) 
Given a permutation vector (i.e. a vector \(p_0\ldots p_{N1}\) where each \(p_i\in [0,N)\) and \(p_i\neq p_j\) for \(i\neq j\)), produce the inverse permutation \(q_0\ldots q_{N1}\) so that \(q_{p_i}=p_{q_i}=i\).
Definition at line 1419 of file utilities.h.
size_t Utilities::pack  (  const T &  object, 
std::vector< char > &  dest_buffer,  
const bool  allow_compression = true 

) 
Given an arbitrary object of type T, use boost::serialization utilities to pack the object into a vector of characters and append it to the given buffer. The number of elements that have been added to the buffer will be returned. The object can be unpacked using the Utilities::unpack function below.
If the library has been compiled with ZLIB enabled, then the output buffer can be compressed. This can be triggered with the parameter allow_compression
, and is only of effect if ZLIB is enabled.
If many consecutive calls with the same buffer are considered, it is recommended for reasons of performance to ensure that its capacity is sufficient.
Definition at line 1182 of file utilities.h.
std::vector< char > Utilities::pack  (  const T &  object, 
const bool  allow_compression = true 

) 
Creates and returns a buffer solely for the given object, using the above mentioned pack function.
If the library has been compiled with ZLIB enabled, then the output buffer can be compressed. This can be triggered with the parameter allow_compression
, and is only of effect if ZLIB is enabled.
Definition at line 1254 of file utilities.h.
T Utilities::unpack  (  const std::vector< char > &  buffer, 
const bool  allow_compression = true 

) 
Given a vector of characters, obtained through a call to the function Utilities::pack, restore its content in an object of type T.
This function uses boost::serialization utilities to unpack the object from a vector of characters, and it is the inverse of the function Utilities::pack().
The allow_compression
parameter denotes if the buffer to read from could have been previously compressed with ZLIB, and is only of effect if ZLIB is enabled.
T
, you must manually specify the template argument when calling this function.Definition at line 1326 of file utilities.h.
T Utilities::unpack  (  const std::vector< char >::const_iterator &  cbegin, 
const std::vector< char >::const_iterator &  cend,  
const bool  allow_compression = true 

) 
Same unpack function as above, but takes constant iterators on (a fraction of) a given packed buffer of type std::vector<char> instead.
The allow_compression
parameter denotes if the buffer to read from could have been previously compressed with ZLIB, and is only of effect if ZLIB is enabled.
Definition at line 1264 of file utilities.h.
void Utilities::unpack  (  const std::vector< char > &  buffer, 
T(&)  unpacked_object[N],  
const bool  allow_compression = true 

) 
Given a vector of characters, obtained through a call to the function Utilities::pack, restore its content in an array of type T.
This function uses boost::serialization utilities to unpack the object from a vector of characters, and it is the inverse of the function Utilities::pack().
The allow_compression
parameter denotes if the buffer to read from could have been previously compressed with ZLIB, and is only of effect if ZLIB is enabled.
Definition at line 1390 of file utilities.h.
void Utilities::unpack  (  const std::vector< char >::const_iterator &  cbegin, 
const std::vector< char >::const_iterator &  cend,  
T(&)  unpacked_object[N],  
const bool  allow_compression = true 

) 
Same unpack function as above, but takes constant iterators on (a fraction of) a given packed buffer of type std::vector<char> instead.
The allow_compression
parameter denotes if the buffer to read from could have been previously compressed with ZLIB, and is only of effect if ZLIB is enabled.
Definition at line 1334 of file utilities.h.
std::unique_ptr<To> Utilities::dynamic_unique_cast  (  std::unique_ptr< From > &&  p  ) 
Convert an object of type std::unique_ptr<From>
to an object of type std::unique_ptr<To>
, where it is assumed that we can cast the pointer to From
to a pointer to To
using a dynamic_cast
– in other words, we assume that From
and To
are connected through a class hierarchy, and that the object pointed to is in fact of a type that contains both a From
and a To
. An example is if either To
is derived from From
or the other way around.
The function throws an exception of type std::bad_cast
if the dynamic_cast
does not succeed. This is the same exception you would get if a regular dynamic_cast
between object types (but not pointer types) does not succeed.
An example of how this function works is as follows:
Deleter
objects stored by std::unique_ptr
objects. The function therefore only works if the deleter objects are at their defaults, i.e., if they are of type std::default_delete<To>
and std::default_delete<From>
. Definition at line 752 of file utilities.h.