csqrtf, csqrt, csqrtl
From cppreference.com
C
Concurrency support (C11)
Complex number arithmetic
Types and the imaginary constant
Manipulation
Power and exponential functions
Trigonometric functions
Hyperbolic functions
Defined in header
<complex.h>
Defined in header
<tgmath.h>
#define sqrt( z )
(4)
(since C99)
1-3) Computes the complex square root of
z with branch cut along the negative real axis.4) Type-generic macro: If
z has type long double complex , csqrtl is called. if z has type double complex , csqrt is called, if z has type float complex , csqrtf is called. If z is real or integer, then the macro invokes the corresponding real function (sqrtf, sqrt , sqrtl). If z is imaginary, the corresponding complex number version is called.Contents
[edit] Parameters
z
-
complex argument
[edit] Return value
If no errors occur, returns the square root of z, in the range of the right half-plane, including the imaginary axis ([0; +∞) along the real axis and (−∞; +∞) along the imaginary axis.)
[edit] Error handling and special values
Errors are reported consistent with math_errhandling
If the implementation supports IEEE floating-point arithmetic,
- The function is continuous onto the branch cut taking into account the sign of imaginary part
- csqrt(conj (z)) == conj (csqrt(z))
- If
zis±0+0i, the result is+0+0i - If
zisx+∞i, the result is+∞+∞ieven if x is NaN - If
zisx+NaNi, the result isNaN+NaNi(unless x is ±∞) and FE_INVALID may be raised - If
zis-∞+yi, the result is+0+∞ifor finite positive y - If
zis+∞+yi, the result is+∞+0i)for finite positive y - If
zis-∞+NaNi, the result isNaN±∞i(sign of imaginary part unspecified) - If
zis+∞+NaNi, the result is+∞+NaNi - If
zisNaN+yi, the result isNaN+NaNiand FE_INVALID may be raised - If
zisNaN+NaNi, the result isNaN+NaNi
[edit] Example
Run this code
#include <stdio.h> #include <complex.h> int main(void) { double complex z1 = csqrt(-4); printf ("Square root of -4 is %.1f%+.1fi\n", creal (z1), cimag (z1)); double complex z2 = csqrt(conj (-4)); // or, in C11, CMPLX(-4, -0.0) printf ("Square root of -4-0i, the other side of the cut, is " "%.1f%+.1fi\n", creal (z2), cimag (z2)); }
Output:
Square root of -4 is 0.0+2.0i Square root of -4-0i, the other side of the cut, is 0.0-2.0i
[edit] References
- C11 standard (ISO/IEC 9899:2011):
- 7.3.8.3 The csqrt functions (p: 196)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- G.6.4.2 The csqrt functions (p: 544)
- G.7 Type-generic math <tgmath.h> (p: 545)
- C99 standard (ISO/IEC 9899:1999):
- 7.3.8.3 The csqrt functions (p: 178)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- G.6.4.2 The csqrt functions (p: 479)
- G.7 Type-generic math <tgmath.h> (p: 480)
[edit] See also
C++ documentation for sqrt