C++

Reference

<valarray>

function template
<valarray>

std::pow

template<class T> valarray<T> pow (const valarray<T>& x, const valarray<T>& y);template<class T> valarray<T> pow (const valarray<T>& x, const T& y);template<class T> valarray<T> pow (const T& x, const valarray<T>& y);
Compute power of valarray elements
Returns a valarray containing the results of the power operation on all the elements, in the same order. The results calculated are x raised to the power y (xy).

The function calls pow (unqualified) once for each element in both x and y; If either is a single T value, it is used for all calls.

This function overloads cmath's pow.

Parameters

x
valarray or element with the bases for the power operations.
y
valarray or element with the exponents for the power operations.
If both arguments are valarray objects and their sizes don't match, the behavior is undefined.

Return value

A valarray object with the values of x to the power of y.

Example

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// pow valarray example
#include <iostream>     // std::cout
#include <cstddef>      // std::size_t
#include <cmath>        // std::pow
#include <valarray>     // std::valarray, std::pow

int main ()
{
  std::valarray<double> val (5);
  std::valarray<double> results;

  for (int i=0; i<5; ++i) val[i]=i+1;
  std::cout << "val:";
  for (std::size_t i=0; i<val.size(); ++i) std::cout << ' ' << val[i];
  std::cout << '\n';

  results = std::pow (val,val);
  std::cout << "val^val:";
  for (std::size_t i=0; i<results.size(); ++i) std::cout << ' ' << results[i];
  std::cout << '\n';

  results = std::pow (val,2.0);
  std::cout << "val^2:";
  for (std::size_t i=0; i<results.size(); ++i) std::cout << ' ' << results[i];
  std::cout << '\n';

  results = std::pow (2.0,val);
  std::cout << "2^val:";
  for (std::size_t i=0; i<results.size(); ++i) std::cout << ' ' << results[i];
  std::cout << '\n';

  return 0;
}

Output:

val: 1 2 3 4 5
val^val: 1 4 27 256 3125
val^2: 1 4 9 16 25
2^val: 2 4 8 16 32


See also

pow (cmath)
Raise to power (function)
log
Compute natural logarithm of valarray elements (function template)
exp
Compute exponential of valarray elements (function template)
sqrt
Compute square root of valarray elements (function template)