log


function template
<valarray> 
template<class T> valarray<T> log (const valarray<T>& x);

Compute natural logarithm of valarray elements

Returns a valarray object containing the natural logarithm (base-e logarithm) of all the elements of x.

This function overloads cmath's log function.

Parameters

x
valarray containing elements of a type for which the unary function log is defined.


Return value

A valarray object with the natural logarithms of the elements of x.

Example

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// log valarray example
#include <iostream>
#include <cmath>
#include <valarray>
using namespace std;

int main ()
{
  double val[] = {5.0, 6.6, 8.0, 9.9};
  valarray<double> foo (val,4);

  valarray<double> bar = log (foo);

  cout << "foo: ";
  for (size_t i=0; i<foo.size(); ++i)
	  cout << foo[i] << ' ';
  cout << endl;

  cout << "bar: ";
  for (size_t i=0; i<bar.size(); ++i)
	  cout << bar[i] << ' ';
  cout << endl;

  return 0;
}


Output:

foo: 5 6.6 8 9.9
bar: 1.60944 1.88707 2.07944 2.29253


See also

log (cmath) Compute natural logarithm (function)
log10 Compute common logarithm of valarray elements (function template)
exp Compute exponential of valarray elements (function template)
pow Compute power of valarray elements (function template)