Difference between revisions of "cpp/numeric/valarray/log"
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Revision as of 23:33, 12 October 2017
| Defined in header <valarray>
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| template< class T > valarray<T> log( const valarray<T>& va ); |
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For each element in va computes natural logarithm of the value of the element.
Contents |
Parameters
| va | - | value array to apply the operation to |
Return value
Value array containing natural logarithms of the values in va.
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.
- For every function taking a const std::valarray<T>& except begin() and end()(since C++11), identical functions taking the replacement types shall be added;
- For every function taking two const std::valarray<T>& arguments, identical functions taking every combination of const std::valarray<T>& and replacement types shall be added.
- The return type does not add more than two levels of template nesting over the most deeply-nested argument type.
Possible implementation
template< class T > valarray<T> log( const valarray<T>& va ) { valarray<T> other = va; for (T &i : other) { i = log(i); } return other; } |
Example
| This section is incomplete Reason: no example |
See also
| applies the function std::log10 to each element of valarray (function template) | |
| applies the function std::exp to each element of valarray (function template) | |
| (C++11)(C++11) |
computes natural (base e) logarithm (ln(x)) (function) |
| complex natural logarithm with the branch cuts along the negative real axis (function template) |
