Difference between revisions of "cpp/numeric/valarray/cos"
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m (impl) |
Andreas Krug (Talk | contribs) m (fmt, {{c}}) |
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{{cpp/title|cos{{small|(std::valarray)}}}} | {{cpp/title|cos{{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> cos( const valarray<T>& va ); | valarray<T> cos( const valarray<T>& va ); | ||
}} | }} | ||
| − | For each element in {{ | + | For each element in {{c|va}} computes cosine 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 cosines of the values in {{ | + | Value array containing cosines of the values in {{c|va}}. |
===Notes=== | ===Notes=== | ||
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===Example=== | ===Example=== | ||
| − | {{example | + | {{example |
| − | + | |code= | |
#include <cmath> | #include <cmath> | ||
#include <iomanip> | #include <iomanip> | ||
| Line 34: | Line 34: | ||
void show(const char* title, const std::valarray<float>& data) | void show(const char* title, const std::valarray<float>& data) | ||
{ | { | ||
| − | const int w { 9 }; | + | const int w{9}; |
std::cout << std::setw(w) << title << " {{!}} "; | std::cout << std::setw(w) << title << " {{!}} "; | ||
for (float x : data) | for (float x : data) | ||
| Line 43: | Line 43: | ||
int main() | int main() | ||
{ | { | ||
| − | const std::valarray<float> x { .1, .2, .3, .4 }; | + | const std::valarray<float> x{.1, .2, .3, .4}; |
const auto sin = std::sin(x); | const auto sin = std::sin(x); | ||
const auto cos = std::cos(x); | const auto cos = std::cos(x); | ||
const auto z = (sin * sin) + (cos * cos); | const auto z = (sin * sin) + (cos * cos); | ||
| − | show("x" | + | show("x", x); |
show("sin(x)", sin); | show("sin(x)", sin); | ||
show("cos(x)", cos); | show("cos(x)", cos); | ||
| − | show("z" | + | show("z", z); |
} | } | ||
| − | + | |output=<nowiki/> | |
x {{!}} 0.1 {{!}} 0.2 {{!}} 0.3 {{!}} 0.4 {{!}} | x {{!}} 0.1 {{!}} 0.2 {{!}} 0.3 {{!}} 0.4 {{!}} | ||
sin(x) {{!}} 0.0998334 {{!}} 0.198669 {{!}} 0.29552 {{!}} 0.389418 {{!}} | sin(x) {{!}} 0.0998334 {{!}} 0.198669 {{!}} 0.29552 {{!}} 0.389418 {{!}} | ||
| Line 62: | Line 62: | ||
===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/numeric/valarray/dsc sin}} | + | {{dsc inc|cpp/numeric/valarray/dsc sin}} |
| − | {{dsc inc | cpp/numeric/valarray/dsc tan}} | + | {{dsc inc|cpp/numeric/valarray/dsc tan}} |
| − | {{dsc inc | cpp/numeric/valarray/dsc acos}} | + | {{dsc inc|cpp/numeric/valarray/dsc acos}} |
| − | {{dsc inc | cpp/numeric/math/dsc cos}} | + | {{dsc inc|cpp/numeric/math/dsc cos}} |
| − | {{dsc inc | cpp/numeric/complex/dsc cos}} | + | {{dsc inc|cpp/numeric/complex/dsc cos}} |
{{dsc end}} | {{dsc end}} | ||
{{langlinks|de|es|fr|it|ja|pt|ru|zh}} | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | ||
Latest revision as of 00:42, 17 October 2023
| Defined in header <valarray>
|
||
| template< class T > valarray<T> cos( const valarray<T>& va ); |
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For each element in va computes cosine of the value of the element.
Contents |
[edit] Parameters
| va | - | value array to apply the operation to |
[edit] Return value
Value array containing cosines of the values in va.
[edit] Notes
Unqualified function (cos) is used to perform the computation. If such function is not available, std::cos 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> cos(const valarray<T>& va) { valarray<T> other = va; for (T& i : other) i = cos(i); return other; // proxy object may be returned } |
[edit] Example
Run this code
#include <cmath> #include <iomanip> #include <iostream> #include <valarray> void show(const char* title, const std::valarray<float>& data) { const int w{9}; std::cout << std::setw(w) << title << " | "; for (float x : data) std::cout << std::setw(w) << x << " | "; std::cout << '\n'; } int main() { const std::valarray<float> x{.1, .2, .3, .4}; const auto sin = std::sin(x); const auto cos = std::cos(x); const auto z = (sin * sin) + (cos * cos); show("x", x); show("sin(x)", sin); show("cos(x)", cos); show("z", z); }
Output:
x | 0.1 | 0.2 | 0.3 | 0.4 |
sin(x) | 0.0998334 | 0.198669 | 0.29552 | 0.389418 |
cos(x) | 0.995004 | 0.980067 | 0.955337 | 0.921061 |
z | 1 | 1 | 1 | 1 |[edit] See also
| applies the function std::sin to each element of valarray (function template) | |
| applies the function std::tan to each element of valarray (function template) | |
| applies the function std::acos to each element of valarray (function template) | |
| (C++11)(C++11) |
computes cosine (cos(x)) (function) |
| computes cosine of a complex number (cos(z)) (function template) |
