log (<valarray>)
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the natural logarithm of the elements of the input valarray.
template<class Type>
valarray<Type> log(
const valarray<Type>& _Left
);
Parameters
- _Left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the absolute value of the elements of the input valarray.
Example
// valarray_log.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
int i;
valarray<double> va1 ( 9 );
for (i = 0 ; i < 9 ; i++ )
va1 [ i ] = 10 * i;
valarray<double> va2 ( 9 );
cout << "Initial valarray:";
for ( i = 0 ; i < 9 ; i++ )
cout << " " << va1 [ i ];
cout << endl;
va2 = log ( va1 );
cout << "The natural logarithm of the initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
Initial valarray: 0 10 20 30 40 50 60 70 80 The natural logarithm of the initial valarray is: -1.#INF 2.30259 2.99573 3.4012 3.68888 3.91202 4.09434 4.2485 4.38203
Requirements
Header: <valarray>
Namespace: std