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