function template
<valarray>
std::log
template<class T> valarray<T> log (const valarray<T>& x);
Compute natural logarithm of valarray elements
Returns a valarray containing the natural logarithm (base-e logarithm) of all the elements of x, in the same order.
The function calls log (unqualified) once for each element.
This function overloads cmath's log.
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> // std::cout #include <cstddef> // std::size_t #include <cmath> // std::log(double) #include <valarray> // std::valarray, std::log(valarray) int main () { double val[] = {5.0, 6.6, 8.0, 9.9}; std::valarray<double> foo (val,4); std::valarray<double> bar = log (foo); std::cout << "foo:"; for (std::size_t i=0; i<foo.size(); ++i) std::cout << ' ' << foo[i]; std::cout << '\n'; std::cout << "bar:"; for (std::size_t i=0; i<bar.size(); ++i) std::cout << ' ' << bar[i]; std::cout << '\n'; 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)