LOG — Natural logarithm function#

LOG(X)#

LOG(X) computes the natural logarithm of X, i.e. the logarithm to the base e.

Parameters

X – The type shall be REAL or COMPLEX.

Returns

The return value is of type REAL or COMPLEX. The kind type parameter is the same as X. If X is COMPLEX, the imaginary part omega is in the range -pi < omega leq pi.

Standard:

Fortran 77 and later, has GNU extensions

Class:

Elemental function

Syntax:
RESULT = LOG(X)
Example:
program test_log
  real(8) :: x = 2.7182818284590451_8
  complex :: z = (1.0, 2.0)
  x = log(x)    ! will yield (approximately) 1
  z = log(z)
end program test_log
Specific names:

Name

Argument

Return type

Standard

ALOG(X)

REAL(4) X

REAL(4)

Fortran 77 or later

DLOG(X)

REAL(8) X

REAL(8)

Fortran 77 or later

CLOG(X)

COMPLEX(4) X

COMPLEX(4)

Fortran 77 or later

ZLOG(X)

COMPLEX(8) X

COMPLEX(8)

GNU extension

CDLOG(X)

COMPLEX(8) X

COMPLEX(8)

GNU extension