Difference between revisions of "cpp/numeric/valarray/atan"
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{{cpp/title|atan{{small|(std::valarray)}}}} | {{cpp/title|atan{{small|(std::valarray)}}}} | ||
{{cpp/numeric/valarray/navbar}} | {{cpp/numeric/valarray/navbar}} | ||
| − | {{ddcl | header=valarray | 1= | + | {{ddcl|header=valarray|1= |
template< class T > | template< class T > | ||
valarray<T> atan( const valarray<T>& va ); | valarray<T> atan( const valarray<T>& va ); | ||
}} | }} | ||
| − | For each element in {{ | + | For each element in {{c|va}} computes arc tangent of the value of the element. |
===Parameters=== | ===Parameters=== | ||
{{par begin}} | {{par begin}} | ||
| − | {{par | va | value array to apply the operation to}} | + | {{par|va|value array to apply the operation to}} |
{{par end}} | {{par end}} | ||
===Return value=== | ===Return value=== | ||
| − | Value array containing arc tangents of the values in {{ | + | Value array containing arc tangents of the values in {{c|va}}. |
===Notes=== | ===Notes=== | ||
| Line 22: | Line 22: | ||
===Possible implementation=== | ===Possible implementation=== | ||
| − | {{ | + | {{cpp/numeric/valarray/impl|atan}} |
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| − | + | ||
| − | + | ||
| − | + | ||
| − | }} | + | |
===Example=== | ===Example=== | ||
{{example | {{example | ||
|code= | |code= | ||
| + | #include <algorithm> | ||
| + | #include <cmath> | ||
| + | #include <iostream> | ||
| + | #include <valarray> | ||
| + | |||
| + | auto show = [](char const* title, const std::valarray<float>& va) | ||
| + | { | ||
| + | std::cout << title << " :"; | ||
| + | std::for_each(std::begin(va), std::end(va), | ||
| + | [](const float x) { std::cout << " " << std::fixed << x; }); | ||
| + | std::cout << '\n'; | ||
| + | }; | ||
| + | |||
| + | int main() | ||
| + | { | ||
| + | const std::valarray<float> x = {.1f, .3f, .6f, .9f}; | ||
| + | const std::valarray<float> f = std::atan(x); | ||
| + | const std::valarray<float> g = std::tan(f); | ||
| + | |||
| + | show("x ", x); | ||
| + | show("f = atan(x)", f); | ||
| + | show("g = tan(f) ", g); | ||
| + | } | ||
|output= | |output= | ||
| + | x : 0.100000 0.300000 0.600000 0.900000 | ||
| + | f = atan(x) : 0.099669 0.291457 0.540420 0.732815 | ||
| + | g = tan(f) : 0.100000 0.300000 0.600000 0.900000 | ||
}} | }} | ||
===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/numeric/valarray/dsc asin}} | + | {{dsc inc|cpp/numeric/valarray/dsc asin}} |
| − | {{dsc inc | cpp/numeric/valarray/dsc acos}} | + | {{dsc inc|cpp/numeric/valarray/dsc acos}} |
| − | {{dsc inc | cpp/numeric/valarray/dsc atan2}} | + | {{dsc inc|cpp/numeric/valarray/dsc atan2}} |
| − | {{dsc inc | cpp/numeric/valarray/dsc tan}} | + | {{dsc inc|cpp/numeric/valarray/dsc tan}} |
| − | {{dsc inc | cpp/numeric/math/dsc atan}} | + | {{dsc inc|cpp/numeric/math/dsc atan}} |
| − | {{dsc inc | cpp/numeric/complex/dsc atan}} | + | {{dsc inc|cpp/numeric/complex/dsc atan}} |
{{dsc end}} | {{dsc end}} | ||
| − | + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | |
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Latest revision as of 00:19, 17 October 2023
| Defined in header <valarray>
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| template< class T > valarray<T> atan( const valarray<T>& va ); |
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For each element in va computes arc tangent of the value of the element.
Contents |
[edit] Parameters
| va | - | value array to apply the operation to |
[edit] Return value
Value array containing arc tangents of the values in va.
[edit] Notes
Unqualified function (atan) is used to perform the computation. If such function is not available, std::atan 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.
[edit] Possible implementation
template<class T> valarray<T> atan(const valarray<T>& va) { valarray<T> other = va; for (T& i : other) i = atan(i); return other; // proxy object may be returned } |
[edit] Example
Run this code
#include <algorithm> #include <cmath> #include <iostream> #include <valarray> auto show = [](char const* title, const std::valarray<float>& va) { std::cout << title << " :"; std::for_each(std::begin(va), std::end(va), [](const float x) { std::cout << " " << std::fixed << x; }); std::cout << '\n'; }; int main() { const std::valarray<float> x = {.1f, .3f, .6f, .9f}; const std::valarray<float> f = std::atan(x); const std::valarray<float> g = std::tan(f); show("x ", x); show("f = atan(x)", f); show("g = tan(f) ", g); }
Output:
x : 0.100000 0.300000 0.600000 0.900000 f = atan(x) : 0.099669 0.291457 0.540420 0.732815 g = tan(f) : 0.100000 0.300000 0.600000 0.900000
[edit] See also
| applies the function std::asin to each element of valarray (function template) | |
| applies the function std::acos to each element of valarray (function template) | |
| applies the function std::atan2 to a valarray and a value (function template) | |
| applies the function std::tan to each element of valarray (function template) | |
| (C++11)(C++11) |
computes arc tangent (arctan(x)) (function) |
| (C++11) |
computes arc tangent of a complex number (arctan(z)) (function template) |
