1CLOG(3) Linux Programmer's Manual CLOG(3)
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6 clog, clogf, clogl - natural logarithm of a complex number
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9 #include <complex.h>
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11 double complex clog(double complex z);
12 float complex clogf(float complex z);
13 long double complex clogl(long double complex z);
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15 Link with -lm.
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18 These functions calculate the complex natural logarithm of z, with a
19 branch cut along the negative real axis.
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21 The logarithm clog() is the inverse function of the exponential
22 cexp(3). Thus, if y = clog(z), then z = cexp(y). The imaginary part
23 of y is chosen in the interval [-pi,pi].
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25 One has:
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27 clog(z) = log(cabs(z)) + I * carg(z)
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29 Note that z close to zero will cause an overflow.
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32 These functions first appeared in glibc in version 2.1.
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35 For an explanation of the terms used in this section, see
36 attributes(7).
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38 ┌─────────────────────────┬───────────────┬─────────┐
39 │Interface │ Attribute │ Value │
40 ├─────────────────────────┼───────────────┼─────────┤
41 │clog(), clogf(), clogl() │ Thread safety │ MT-Safe │
42 └─────────────────────────┴───────────────┴─────────┘
44 C99, POSIX.1-2001, POSIX.1-2008.
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47 cabs(3), cexp(3), clog10(3), clog2(3), complex(7)
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50 This page is part of release 5.02 of the Linux man-pages project. A
51 description of the project, information about reporting bugs, and the
52 latest version of this page, can be found at
53 https://www.kernel.org/doc/man-pages/.
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57 2017-09-15 CLOG(3)