std::proj(std::complex)
From cppreference.com
Defined in header <complex>
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template
<
class T >
std::complex <T> proj( const std::complex <T> & z ) ; |
(1) | (since C++11) |
Additional overloads (since C++11) |
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Defined in header <complex>
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| (A) | ||
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std::complex
<
float
> proj(
float f )
;
std::complex
<
double
> proj(
double f )
;
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(until C++23) | |
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template
<
class FloatingPoint >
std::complex <FloatingPoint> proj( FloatingPoint f ) ; |
(since C++23) | |
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template
<
class Integer >
std::complex < double > proj( Integer i ) ; |
(B) | |
For most z,
std::proj(z) == z
, but all complex infinities, even the numbers where one component is infinite and the other is NaN, become positive real infinity, (INFINITY, 0.0) or
(INFINITY, -0.0)
. The sign of the imaginary (zero) component is the sign of std::imag(z)
A,B) Additional overloads are provided for all integer and floating-point types, which are treated as complex numbers with positive zero imaginary component.
Parameters
| z | - | complex value |
| f | - | floating-point value |
| i | - | integer value |
Return value
1) The projection of z onto the Riemann sphere.
A) The projection of std::complex(f)
B) The projection of
std::complex
<
double
>
(i)
Notes
The proj
The additional overloads are not required to be provided exactly as (A,B). They only need to be sufficient to ensure that for their argument num:
- If num has a standard(until C++23) floating-point type
T, then std::proj(num) has the same effect as std:: proj ( std::complex <T> (num) ) - Otherwise, if num has an integer type, then std::proj(num) has the same effect as std:: proj ( std::complex < double > (num) )
Example
Run this code
#include <complex> #include <iostream> int main() { std::complex<double> c1(1, 2); std::cout << "proj" << c1 << " = " << std::proj(c1) << '\n'; std::complex<double> c2(INFINITY, -1); std::cout << "proj" << c2 << " = " << std::proj(c2) << '\n'; std::complex<double> c3(0, -INFINITY); std::cout << "proj" << c3 << " = " << std::proj(c3) << '\n'; }
Output:
proj(1,2) = (1,2) proj(inf,-1) = (inf,-0) proj(0,-inf) = (inf,-0)
See also
| returns the magnitude of a complex number (function template) |
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| returns the squared magnitude (function template) |
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| constructs a complex number from magnitude and phase angle (function template) |
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C documentation for cproj
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