cprojf, cproj, cprojl

From cppreference.com
< c‎ | numeric‎ | complex
Defined in header <complex.h>
float complex       cprojf( float complex z ) ;
(1) (since C99)
double complex      cproj( double complex z ) ;
(2) (since C99)
long double complex cprojl( long double complex z ) ;
(3) (since C99)
Defined in header <tgmath.h>
#define cproj( z )
(4) (since C99)
1-3) Computes the projection of z on the Riemann sphere.
4) Type-generic macro: if z has type long double complex, long double imaginary, or long double, cprojl is called. If z has type float complex, float imaginary, or float, cprojf is called. If z has type double complex, double imaginary, double, or any integer type, cproj

For most z, cproj(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*I or INFINITY-0.0*I. The sign of the imaginary (zero) component is the sign of cimag(z)

Parameters

z - complex argument

Return value

The projection of z on the Riemann sphere.

This function is fully specified for all possible inputs and is not subject to any errors described in math_errhandling

Notes

The cproj

Example

#include <stdio.h>
#include <complex.h>
#include <math.h>
 
int main(void)
{
    double complex z1 = cproj(1 + 2*I);
    printf("cproj(1+2i) = %.1f%+.1fi\n", creal(z1),cimag(z1));
 
    double complex z2 = cproj(INFINITY+2.0*I);
    printf("cproj(Inf+2i) = %.1f%+.1fi\n", creal(z2),cimag(z2));
 
    double complex z3 = cproj(INFINITY-2.0*I);
    printf("cproj(Inf-2i) = %.1f%+.1fi\n", creal(z3),cimag(z3));
}

Output:

cproj(1+2i) = 1.0+2.0i
cproj(Inf+2i) = inf+0.0i
cproj(Inf-2i) = inf-0.0i

References

  • C11 standard (ISO/IEC 9899:2011):
  • 7.3.9.5 The cproj functions (p: 198)
  • 7.25 Type-generic math <tgmath.h> (p: 373-375)
  • G.7 Type-generic math <tgmath.h> (p: 545)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.3.9.4 The cproj functions (p: 179)
  • 7.22 Type-generic math <tgmath.h> (p: 335-337)
  • G.7 Type-generic math <tgmath.h> (p: 480)

See also