cpowf, cpow, cpowl

From cppreference.com
Defined in header <complex.h>
float complex cpowf ( float complex x, float complex y ) ;
(1) (since C99)
double complex cpow ( double complex x, double complex y ) ;
(2) (since C99)
long double complex cpowl ( long double complex x, long double complex y ) ;
(3) (since C99)
Defined in header <tgmath.h>
#define pow( x, y )
(4) (since C99)
1-3) Computes the complex power function x y , with branch cut for the first parameter along the negative real axis.
4) Type-generic macro: If any argument has type long double complex , cpowl is called. if any argument has type double complex , cpow is called, if any argument has type float complex , cpowf is called. If the arguments are real or integer, then the macro invokes the corresponding real function ( powf , pow , powl ). If any argument is imaginary, the corresponding complex number version is called.

Parameters

x, y - complex argument

Return value

If no errors occur, the complex power x y , is returned.

Errors and special cases are handled as if the operation is implemented by cexp ( y * clog ( x ) ) , except that the implementation is allowed to treat special cases more carefully.

Example

#include <stdio.h>
#include <complex.h>
 
int main(void)
{    
    double complex z = cpow(1.0+2.0*I, 2);
    printf("(1+2i)^2 = %.1f%+.1fi\n", creal(z), cimag(z));
 
    double complex z2 = cpow(-1, 0.5);
    printf("(-1+0i)^0.5 = %.1f%+.1fi\n", creal(z2), cimag(z2));
 
    double complex z3 = cpow(conj(-1), 0.5); // other side of the cut
    printf("(-1-0i)^0.5 = %.1f%+.1fi\n", creal(z3), cimag(z3));
 
    double complex z4 = cpow(I, I); // i^i = exp(-pi/2)
    printf("i^i = %f%+fi\n", creal(z4), cimag(z4));
}

Output:

(1+2i)^2 = -3.0+4.0i
(-1+0i)^0.5 = 0.0+1.0i
(-1-0i)^0.5 = 0.0-1.0i
i^i = 0.207880+0.000000i

References

  • C11 standard (ISO/IEC 9899:2011):
  • 7.3.8.2 The cpow functions (p: 195-196)
  • 7.25 Type-generic math <tgmath.h> (p: 373-375)
  • G.6.4.1 The cpow functions (p: 544)
  • G.7 Type-generic math <tgmath.h> (p: 545)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.3.8.2 The cpow functions (p: 177)
  • 7.22 Type-generic math <tgmath.h> (p: 335-337)
  • G.6.4.1 The cpow functions (p: 479)
  • G.7 Type-generic math <tgmath.h> (p: 480)

See also

(C99) (C99) (C99)
computes the complex square root
(function)
(C99) (C99)
computes a number raised to the given power ( x y )
(function)