Teuchos::ScalarTraits< T > Struct Template Reference

This structure defines some basic traits for a scalar field type. More...

#include <Teuchos_ScalarTraits.hpp>

List of all members.

Public Types
typedef T	magnitudeType
	Mandatory typedef for result of magnitude.
typedef T	halfPrecision
	Typedef for half precision.
typedef T	doublePrecision
	Typedef for double precision.
Static Public Member Functions
static magnitudeType	eps ()
	Returns relative machine precision.
static magnitudeType	sfmin ()
	Returns safe minimum (sfmin), such that 1/sfmin does not overflow.
static magnitudeType	base ()
	Returns the base of the machine.
static magnitudeType	prec ()
	Returns eps*base.
static magnitudeType	t ()
	Returns the number of (base) digits in the mantissa.
static magnitudeType	rnd ()
	Returns 1.0 when rounding occurs in addition, 0.0 otherwise.
static magnitudeType	emin ()
	Returns the minimum exponent before (gradual) underflow.
static magnitudeType	rmin ()
	Returns the underflow threshold - base^(emin-1).
static magnitudeType	emax ()
	Returns the largest exponent before overflow.
static magnitudeType	rmax ()
	Overflow theshold - (base^emax)*(1-eps).
static magnitudeType	magnitude (T a)
	Returns the magnitudeType of the scalar type a.
static T	zero ()
	Returns representation of zero for this scalar type.
static T	one ()
	Returns representation of one for this scalar type.
static magnitudeType	real (T a)
	Returns the real part of the scalar type a.
static magnitudeType	imag (T a)
	Returns the imaginary part of the scalar type a.
static T	conjugate (T a)
	Returns the conjugate of the scalar type a.
static T	nan ()
	Returns a number that represents NaN.
static bool	isnaninf (const T &x)
	Returns true if x is NaN or Inf.
static void	seedrandom (unsigned int s)
	Seed the random number generator returned by random().
static T	random ()
	Returns a random number (between -one() and +one()) of this scalar type.
static std::string	name ()
	Returns the name of this scalar type.
static T	squareroot (T x)
	Returns a number of magnitudeType that is the square root of this scalar type x.
static T	pow (T x, T y)
	Returns the result of raising one scalar x to the power y.
Static Public Attributes
static const bool	isComplex = false
	Determines if scalar type is std::complex.
static const bool	isOrdinal = false
	Determines if scalar type is an ordinal type.
static const bool	isComparable = false
	Determines if scalar type supports relational operators such as <, >, <=, >=.
static const bool	hasMachineParameters = false
	Determines if scalar type have machine-specific parameters (i.e. eps(), sfmin(), base(), prec(), t(), rnd(), emin(), rmin(), emax(), rmax() are supported).

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Detailed Description

template<class T>
struct Teuchos::ScalarTraits< T >

This structure defines some basic traits for a scalar field type.

Scalar traits are an essential part of templated codes. This structure offers the basic traits of the templated scalar type, like defining zero and one, and basic functions on the templated scalar type, like performing a square root.

The functions in the templated base unspecialized struct are designed not to compile (giving a nice compile-time error message) and therefore specializations must be written for Scalar types actually used.

Note:

1. The default defined specializations are provided for int, float, and double.
2. ScalarTraits can be used with the Arbitrary Precision Library ( http://crd.lbl.gov/~dhbailey/mpdist/ ) by configuring Teuchos with --enable-teuchos-arprec and giving the appropriate paths to ARPREC. Then ScalarTraits has the specialization: mp_real.
3. If Teuchos is configured with --enable-teuchos-stdcomplex then ScalarTraits also has a parital specialization for all std::complex numbers of the form std::complex<T>.

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Member Typedef Documentation

template<class T>

typedef T Teuchos::ScalarTraits< T >::magnitudeType

Mandatory typedef for result of magnitude.

template<class T>

typedef T Teuchos::ScalarTraits< T >::halfPrecision

Typedef for half precision.

template<class T>

typedef T Teuchos::ScalarTraits< T >::doublePrecision

Typedef for double precision.

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Member Function Documentation

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::eps

(

)

[inline, static]

Returns relative machine precision.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::sfmin

(

)

[inline, static]

Returns safe minimum (sfmin), such that 1/sfmin does not overflow.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::base

(

)

[inline, static]

Returns the base of the machine.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::prec

(

)

[inline, static]

Returns eps*base.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::t

(

)

[inline, static]

Returns the number of (base) digits in the mantissa.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::rnd

(

)

[inline, static]

Returns 1.0 when rounding occurs in addition, 0.0 otherwise.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::emin

(

)

[inline, static]

Returns the minimum exponent before (gradual) underflow.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::rmin

(

)

[inline, static]

Returns the underflow threshold - base^(emin-1).

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::emax

(

)

[inline, static]

Returns the largest exponent before overflow.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::rmax

(

)

[inline, static]

Overflow theshold - (base^emax)*(1-eps).

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::magnitude

(

T

a

)

[inline, static]

Returns the magnitudeType of the scalar type a.

template<class T>

static T Teuchos::ScalarTraits< T >::zero

(

)

[inline, static]

Returns representation of zero for this scalar type.

template<class T>

static T Teuchos::ScalarTraits< T >::one

(

)

[inline, static]

Returns representation of one for this scalar type.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::real

(

T

a

)

[inline, static]

Returns the real part of the scalar type a.

template<class T>

static magnitudeType Teuchos::ScalarTraits< T >::imag

(

T

a

)

[inline, static]

Returns the imaginary part of the scalar type a.

template<class T>

static T Teuchos::ScalarTraits< T >::conjugate

(

T

a

)

[inline, static]

Returns the conjugate of the scalar type a.

template<class T>

static T Teuchos::ScalarTraits< T >::nan

(

)

[inline, static]

Returns a number that represents NaN.

template<class T>

static bool Teuchos::ScalarTraits< T >::isnaninf

(

const T &

x

)

[inline, static]

Returns true if x is NaN or Inf.

template<class T>

static void Teuchos::ScalarTraits< T >::seedrandom

(

unsigned int

s

)

[inline, static]

Seed the random number generator returned by random().

template<class T>

static T Teuchos::ScalarTraits< T >::random

(

)

[inline, static]

Returns a random number (between -one() and +one()) of this scalar type.

template<class T>

static std::string Teuchos::ScalarTraits< T >::name

(

)

[inline, static]

Returns the name of this scalar type.

template<class T>

static T Teuchos::ScalarTraits< T >::squareroot

(

T

x

)

[inline, static]

Returns a number of magnitudeType that is the square root of this scalar type x.

template<class T>

static T Teuchos::ScalarTraits< T >::pow	(	T	x,
		T	y
	)			[inline, static]

Returns the result of raising one scalar x to the power y.

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Member Data Documentation

template<class T>

const bool Teuchos::ScalarTraits< T >::isComplex = false [static]

Determines if scalar type is std::complex.

template<class T>

const bool Teuchos::ScalarTraits< T >::isOrdinal = false [static]

Determines if scalar type is an ordinal type.

template<class T>

const bool Teuchos::ScalarTraits< T >::isComparable = false [static]

Determines if scalar type supports relational operators such as <, >, <=, >=.

template<class T>

const bool Teuchos::ScalarTraits< T >::hasMachineParameters = false [static]

Determines if scalar type have machine-specific parameters (i.e. eps(), sfmin(), base(), prec(), t(), rnd(), emin(), rmin(), emax(), rmax() are supported).

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The documentation for this struct was generated from the following file:

• Teuchos_ScalarTraits.hpp

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