Reference documentation for deal.II version Git ab1cc5b 2017-03-24 06:23:49 -0600
numbers Namespace Reference

## Classes

struct  NumberTraits

struct  NumberTraits< std::complex< number > >

## Functions

bool is_nan (const double x)

bool is_finite (const double x)

bool is_finite (const std::complex< double > &x)

bool is_finite (const std::complex< float > &x)

bool is_finite (const std::complex< long double > &x)

template<class T >
signaling_nan ()

## Variables

static const double E = 2.7182818284590452354

static const double LOG2E = 1.4426950408889634074

static const double LOG10E = 0.43429448190325182765

static const double LN2 = 0.69314718055994530942

static const double LN10 = 2.30258509299404568402

static const double PI = 3.14159265358979323846

static const double PI_2 = 1.57079632679489661923

static const double PI_4 = 0.78539816339744830962

static const double SQRT2 = 1.41421356237309504880

static const double SQRT1_2 = 0.70710678118654752440

static const unsigned int invalid_unsigned_int = static_cast<unsigned int> (-1)

const types::global_dof_index invalid_size_type = static_cast<types::global_dof_index> (-1)

const types::global_dof_index invalid_dof_index = static_cast<types::global_dof_index>(-1)

const types::material_id invalid_material_id = static_cast<types::material_id>(-1)

const types::boundary_id invalid_boundary_id = static_cast<types::boundary_id>(-1)

const types::boundary_id internal_face_boundary_id = static_cast<types::boundary_id>(-1)

const types::manifold_id invalid_manifold_id = static_cast<types::manifold_id>(-1)

const types::manifold_id flat_manifold_id = static_cast<types::manifold_id>(-1)

const types::subdomain_id invalid_subdomain_id = static_cast<types::subdomain_id>(-1)

const types::subdomain_id artificial_subdomain_id = static_cast<types::subdomain_id>(-2)

## Detailed Description

Namespace for the declaration of universal constants. Since the availability in math.h is not always guaranteed, we put them here. Since this file is included by base/config.h, they are available to the whole library.

The constants defined here are a subset of the M_XXX constants sometimes declared in the system include file math.h, but without the prefix M_.

In addition to that, we declare invalid_unsigned_int to be the largest unsigned integer representable; this value is widely used in the library as a marker for an invalid index, an invalid size of an array, and similar purposes.

## Function Documentation

 bool numbers::is_nan ( const double x )
inline

Check whether a value is not a number.

This function uses either std::isnan, isnan, or _isnan, whichever is available on the system and returns the result.

If none of the functions detecting NaN is available, this function returns false.

Definition at line 262 of file numbers.h.

 bool numbers::is_finite ( const double x )
inline

Return true if the given value is a finite floating point number, i.e. is neither plus or minus infinity nor NaN (not a number).

Note that the argument type of this function is double. In other words, if you give a very large number of type long double, this function may return false even if the number is finite with respect to type long double.

Definition at line 275 of file numbers.h.

 bool numbers::is_finite ( const std::complex< double > & x )
inline

Return true if real and imaginary parts of the given complex number are finite.

Definition at line 291 of file numbers.h.

 bool numbers::is_finite ( const std::complex< float > & x )
inline

Return true if real and imaginary parts of the given complex number are finite.

Definition at line 302 of file numbers.h.

 bool numbers::is_finite ( const std::complex< long double > & x )
inline

Return true if real and imaginary parts of the given complex number are finite.

Again may not work correctly if real or imaginary parts are very large numbers that are infinite in terms of double, but finite with respect to long double.

Definition at line 313 of file numbers.h.

template<class T >
 T numbers::signaling_nan ( )

Provide an object of type T filled with a signaling NaN that will cause an exception when used in a computation. The content of these objects is a "signaling NaN" ("NaN" stands for "not a number", and "signaling" implies that at least on platforms where this is supported, any arithmetic operation using them terminates the program). The purpose of such objects is to use them as markers for uninitialized objects and arrays that are required to be filled in other places, and to trigger an error when this later initialization does not happen before the first use.

Template Parameters
 T The type of the returned invalid object. This type can either be a scalar, or of type Tensor, SymmetricTensor, or DerivativeForm. Other types may be supported if there is a corresponding specialization of the internal::SignalingNaN::NaNInitializer class for this type.
Note
Because the type T is not used as a function argument, the compiler cannot deduce it from the type of arguments. Consequently, you have to provide it explicitly. For example, the line
Tensor<1,dim> tensor = Utilities::signaling_nan<Tensor<1,dim> >();
initializes a tensor with invalid values.

Definition at line 219 of file signaling_nan.h.

## Variable Documentation

 const double numbers::E = 2.7182818284590452354
static

e

Definition at line 69 of file numbers.h.

 const double numbers::LOG2E = 1.4426950408889634074
static

log_2 e

Definition at line 74 of file numbers.h.

 const double numbers::LOG10E = 0.43429448190325182765
static

log_10 e

Definition at line 79 of file numbers.h.

 const double numbers::LN2 = 0.69314718055994530942
static

log_e 2

Definition at line 84 of file numbers.h.

 const double numbers::LN10 = 2.30258509299404568402
static

log_e 10

Definition at line 89 of file numbers.h.

 const double numbers::PI = 3.14159265358979323846
static

pi

Definition at line 94 of file numbers.h.

 const double numbers::PI_2 = 1.57079632679489661923
static

pi/2

Definition at line 99 of file numbers.h.

 const double numbers::PI_4 = 0.78539816339744830962
static

pi/4

Definition at line 104 of file numbers.h.

 const double numbers::SQRT2 = 1.41421356237309504880
static

sqrt(2)

Definition at line 109 of file numbers.h.

 const double numbers::SQRT1_2 = 0.70710678118654752440
static

1/sqrt(2)

Definition at line 114 of file numbers.h.

 const unsigned int numbers::invalid_unsigned_int = static_cast (-1)
static

Representation of the largest number that can be put into an unsigned integer. This value is widely used throughout the library as a marker for an invalid unsigned integer value, such as an invalid array index, an invalid array size, and the like.

Definition at line 170 of file types.h.

 const types::global_dof_index numbers::invalid_size_type = static_cast (-1)

Representation of the largest number that can be put into a size_type. This value is used throughout the library as a marker for an invalid size_type value, such as an invalid array index, an invalid array size, and the like. Invalid_size_type is equivalent to invalid_dof_index.

Definition at line 179 of file types.h.

 const types::global_dof_index numbers::invalid_dof_index = static_cast(-1)

An invalid value for indices of degrees of freedom.

Definition at line 184 of file types.h.

 const types::material_id numbers::invalid_material_id = static_cast(-1)

Invalid material_id which we need in several places as a default value. We assume that all material_ids lie in the range [0, invalid_material_id).

Definition at line 191 of file types.h.

 const types::boundary_id numbers::invalid_boundary_id = static_cast(-1)

Invalid boundary_id which we need in several places as a default value. We assume that all valid boundary_ids lie in the range [0, invalid_boundary_id).

Glossary entry on boundary indicators

Definition at line 201 of file types.h.

 const types::boundary_id numbers::internal_face_boundary_id = static_cast(-1)

A boundary indicator number that we reserve for internal faces. We assume that all valid boundary_ids lie in the range [0, internal_face_boundary_id).

This is an indicator that is used internally (by the library) to differentiate between faces that lie at the boundary of the domain and faces that lie in the interior of the domain. You should never try to assign this boundary indicator to anything in user code.

Glossary entry on boundary indicators

Definition at line 216 of file types.h.

 const types::manifold_id numbers::invalid_manifold_id = static_cast(-1)

Invalid manifold_id which we need in several places as a default value. We assume that all valid manifold_ids lie in the range [0, invalid_manifold_id).

Glossary entry on manifold indicators

Definition at line 226 of file types.h.

 const types::manifold_id numbers::flat_manifold_id = static_cast(-1)

A manifold_id we reserve for the default flat Cartesian manifold.

Glossary entry on manifold indicators

Definition at line 234 of file types.h.

 const types::subdomain_id numbers::invalid_subdomain_id = static_cast(-1)

A special id for an invalid subdomain id. This value may not be used as a valid id but is used, for example, for default arguments to indicate a subdomain id that is not to be used.