std::abs(std::valarray)

 

C++

Language

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Technical Specifications

 

Numerics library

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std::valarray

Member functions
valarray::valarray valarray::~valarray valarray::operator= valarray::operator[] valarray::swap valarray::size valarray::resize valarray::sum valarray::min valarray::max valarray::shift valarray::cshift valarray::apply	valarray::operator+valarray::operator-valarray::operator~valarray::operator! valarray::operator+=valarray::operator-=valarray::operator*=valarray::operator/=valarray::operator%=valarray::operator&=valarray::operator|=valarray::operator^=valarray::operator<<=valarray::operator>>=
Non-member functions
swap (C++11) begin (C++11) end (C++11) abs exp log log10 pow sqrt sin cos tan asin acos atan atan2 sinh cosh tanh	operator*operator/operator%operator+operator-operator^operator&operator|operator<<operator>>operator&&operator|| operator==operator!=operator<operator>operator<=operator>=
Helper classes
slice_array gslice_array indirect_array	slice gslice mask_array

 

Defined in header <valarray>
template< class T > valarray<T> abs( const valarray<T>& va );

Computes absolute value of each element in the value array.

Parameters

va

-

value array to apply the operation to

Return value

Value array containing absolute values of the values in va.

Notes

Unqualified function (abs) is used to perform the computation. If such function is not available, std::abs is used due to argument dependent lookup.

The function can be implemented with the return type different from std::valarray. In this case, the replacement type has the following properties:

• All const member functions of std::valarray are provided.
• std::valarray, std::slice_array, std::gslice_array, std::mask_array and std::indirect_array can be constructed from the replacement type.
• All functions accepting an argument of type const std::valarray& except begin() and end() (since C++14) should also accept the replacement type.
• All functions accepting two arguments of type const std::valarray& should accept every combination of const std::valarray& and the replacement type.
• The return type does not add more than two levels of template nesting over the most deeply-nested argument type.

Possible implementation

template< class T > valarray<T> abs( const valarray<T>& va ) { valarray<T> other = va; for (T &i : other) { i = abs(i); } return other; // proxy object may be returned }

Example

Run this code

#include <valarray>
#include <iostream>
 
int main()
{
    std::valarray<int> v{1, -2, 3, -4, 5, -6, 7, -8};
    std::valarray<int> v2 = std::abs(v);
    for(auto n : v2) {
        std::cout << n << ' ';
    }
    std::cout << '\n';
}

Output:

1 2 3 4 5 6 7 8

See also

abs(int)labsllabs (C++11)	computes absolute value of an integral value (|x|) (function)
abs(float) fabs	absolute value of a floating point value (|x|) (function)
abs(std::complex)	returns the magnitude of a complex number (function template)