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# std::log(std::valarray)

From cppreference.com
< cpp‎ | numeric‎ | valarray

Defined in header `<valarray>` |  |
template< class T > valarray<T> log( const valarray<T>& va ); |  |

For each element in `va` computes natural logarithm of the value of the element.

### [edit] Parameters

va | - | value array to apply the operation to

### [edit] Return value

Value array natural logarithms of the values in `va`.

### [edit] Notes

Unqualified function (log) is used to perform the computation. If such function is not available, std::log 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 a arguments of type const std::valarray& 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.

### [edit] Possible implementation

    template< class T >
    valarray<T> log( const valarray<T>& va )
    {
        valarray<T> other = va;
        for (T &i : other) {
            i = log(i);
        }
    }

### [edit] Example

| This section is incomplete Reason: no example

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