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NAME
log2 - base 10 logarithm
SYNOPSIS
log2(x [,eps])
TYPES
x nonzero real or complex
eps 0 < real < 1, defaults to epsilon()
return real or complex
DESCRIPTION
Approximate the base 2 logarithm function of x by a multiple of
epsilon, the error having absolute value less than 0.75 * eps.
When x is an integer power of 2, log2(x) will return an integer
regardless of the value of eps or epsilon().
If y is a positive integer, log2(x, 2^-y) will usually be correct
to the y-th decimal place.
EXAMPLE
; print log2(2), log2(4), log2(1024), log2(2^500), log2(1/2^23209)
1 2 10 500 -23209
; print log2(127), log2(23209), log2(2^17-19)
6.98868468677216585326 14.50239674255407864468 16.99979085393743521984
; print log2(-127)
6.98868468677216585326+4.53236014182719380961i
; print log2(2+3i), log2(-2+3i)
1.85021985907054608020+1.41787163074572199658i 1.85021985907054608020+3.11448851108147181304i
; print log2(2-3i), log2(-2-3i)
1.85021985907054608020-1.41787163074572199658i 1.85021985907054608020-3.11448851108147181304i
; print log2(17+0.3i, 1e-75), log2(-17-0.3i, 1e-75)
4.08768744737521449955+0.02545668190826163773i 4.08768744737521449955-4.50690345991893217190i
LIMITS
x != 0
0 < eps < 1
LINK LIBRARY
NUMBER *qlog2(NUMBER *x, NUMBER *eps)
COMPLEX *c_log2(COMPLEX *x, NUMBER *eps)
SEE ALSO
ilog, ilogn, ilog10, ilog2, ln, log, logn
## Copyright (C) 2023 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.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 2023/08/19 09:14:04
## File existed as early as: 2023
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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