log

来自「Calc Software Package for Number Calc」· 代码 · 共 65 行

NAME
    log	-  base 10 logarithm

SYNOPSIS
    log(x [,eps])

TYPES
    x		nonzero real or complex
    eps		nonzero real, defaults to epsilon()

    return	real or complex

DESCRIPTION
    Approximate the base 10 logarithm function of x by a multiple of
    epsilon, the error having absolute value less than 0.75 * eps.
    If n is a positive integer, log(x, 10^-n) will usually be correct
    to the n-th decimal place.

EXAMPLE
    ; print log(10), log(100), log(1e10), log(1e500)
    1 2 10 500

    ; print log(128), log(23209), log(2^17-19)
    ~2.10720996964786836649 ~4.36565642852838930424 ~5.11744696704937330414

    ; print log(2+3i, 1e-5)
    ~0.55696845725899964822+~0.42681936428109216144i

LIMITS
    x != 0
    eps > 0

LINK LIBRARY
    NUMBER *qlog(NUMBER *x, NUMBER *eps)
    COMPLEX *c_log(COMPLEX *x, NUMBER *eps)

SEE ALSO
    ln

## Copyright (C) 2006  Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL.  You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
##
## @(#) $Revision: 29.1 $
## @(#) $Id: log,v 29.1 2006/05/07 12:59:00 chongo Exp $
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/log,v $
##
## Under source code control:	2006/05/06 23:56:04
## File existed as early as:	2006
##
## chongo <was here> /\oo/\	http://www.isthe.com/chongo/
## Share and enjoy!  :-)	http://www.isthe.com/chongo/tech/comp/calc/