6.2.42 clog Function

Calculates the complex base-$e$ logarithm of a double precision complex value.

Include

<complex.h>

Prototype

double complex clog(double complex z);

Argument

z

value for which to return the complex base-$e$ logarithm

Return Value

Returns the complex base-$e$ (natural) logarithm of z, with no bound along the real axis, in the interval $\mathrm{[-i\pi ,\; +i\pi ]}$ along the imaginary axis, with a branch cut along the negative real axis.

Example

See the notes at the beginning of this chapter or section for information on using printf() or scanf() (and other functions reading and writing the stdin or stdout streams) in the example code.

#include <stdio.h>
#include <complex.h>

int main(void)
{
  double complex x, y;

  x = -2.0 + 1.0*I;
  y = clog(x);
  printf("The complex base-e logarithm of %f + %fi is %f + %fi\n", creal(x), cimag(x), creal(y), cimag(y));
}

Example Output

The complex base-e logarithm of -2.000000 + 1.000000i is 0.804719 + 2.677945i