blaze::SubTrait< T1, T2, typename > Struct Template Reference

Base template for the SubTrait class. More...

#include <SubTrait.h>

Detailed Description

template<typename T1, typename T2, typename>
struct blaze::SubTrait< T1, T2, typename >

Base template for the SubTrait class.

General

The SubTrait class template offers the possibility to select the resulting data type of a generic subtraction operation between the two given types T1 and T2. SubTrait defines the nested type Type, which represents the resulting data type of the subtraction. In case the two types T1 and T2 cannot be subtracted, a compilation error is created. Note that const and volatile qualifiers and reference modifiers are generally ignored.


Creating custom specializations

SubTrait is guaranteed to work for all built-in data types, complex numbers, all vector and matrix types of the Blaze library (including views and adaptors) and all data types that provide a subtraction operator (i.e. operator-). In order to add support for user-defined data types that either don't provide a subtraction operator or whose subtraction operator returns a proxy object instead of a concrete type (as it is for instance common in expression template libraries) it is possible to specialize the SubTrait template. The following example shows the according specialization for the subtraction between two dynamic column vectors:

template< typename T1, typename T2 >
struct SubTrait< DynamicVector<T1,columnVector>, DynamicVector<T2,columnVector> >
{
using Type = DynamicVector< typename SubTrait<T1,T2>::Type, columnVector >;
};


Examples

The following example demonstrates the use of the SubTrait template, where depending on the two given data types the resulting data type is selected:

template< typename T1, typename T2 > // The two generic types
typename SubTrait<T1,T2>::Type // The resulting generic return type
sub( const T1& t1, const T2& t2 ) //
{ // The function 'sub' returns the
return t1 - t2; // difference of the two given values
} //

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