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

Madatory typedef for result of magnitude.

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Member Function Documentation

template<class T> magnitudeType Teuchos::ScalarTraits< T >::eps (   )  [inline, static]

Returns relative machine precision.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::sfmin (   )  [inline, static]

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

template<class T> magnitudeType Teuchos::ScalarTraits< T >::base (   )  [inline, static]

Returns the base of the machine.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::prec (   )  [inline, static]

Returns eps*base.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::t (   )  [inline, static]

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

template<class T> magnitudeType Teuchos::ScalarTraits< T >::rnd (   )  [inline, static]

Returns 1.0 when rounding occurs in addition, 0.0 otherwise.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::emin (   )  [inline, static]

Returns the minimum exponent before (gradual) underflow.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::rmin (   )  [inline, static]

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

template<class T> magnitudeType Teuchos::ScalarTraits< T >::emax (   )  [inline, static]

Returns the largest exponent before overflow.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::rmax (   )  [inline, static]

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

template<class T> magnitudeType Teuchos::ScalarTraits< T >::magnitude (  T  a  )  [inline, static]

Returns the magnitudeType of the scalar type a.

template<class T> T Teuchos::ScalarTraits< T >::zero (   )  [inline, static]

Returns representation of zero for this scalar type.

template<class T> T Teuchos::ScalarTraits< T >::one (   )  [inline, static]

Returns representation of one for this scalar type.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::real (  T  a  )  [inline, static]

Returns the real part of the scalar type a.

template<class T> magnitudeType Teuchos::ScalarTraits< T >::imag (  T  a  )  [inline, static]

Returns the imaginary part of the scalar type a.

template<class T> T Teuchos::ScalarTraits< T >::conjugate (  T  a  )  [inline, static]

Returns the conjugate of the scalar type a.

template<class T> T Teuchos::ScalarTraits< T >::nan (   )  [inline, static]

Returns a number that represents NaN.

template<class T> bool Teuchos::ScalarTraits< T >::isnaninf (  const T &  x  )  [inline, static]

Returns true if x is NaN or Inf.

template<class T> void Teuchos::ScalarTraits< T >::seedrandom (  unsigned int  s  )  [inline, static]

Seed the random number generator returned by random().

template<class T> T Teuchos::ScalarTraits< T >::random (   )  [inline, static]

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

template<class T> std::string Teuchos::ScalarTraits< T >::name (   )  [inline, static]

Returns the name of this scalar type.

template<class T> 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> 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 >::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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