mirror of
https://github.com/lcn2/calc.git
synced 2025-08-16 01:03:29 +03:00
db77e29a23
Converted all ASCII tabs to ASCII spaces using a 8 character tab stop, for all files, except for all Makefiles (plus rpm.mk). The `git diff -w` reports no changes.
70 lines
2.4 KiB
Plaintext
70 lines
2.4 KiB
Plaintext
NAME
|
|
minv - inverse of an integer modulo a specified integer
|
|
|
|
SYNOPSIS
|
|
minv(x, md)
|
|
|
|
TYPES
|
|
x integer
|
|
md integer
|
|
|
|
return integer
|
|
|
|
DESCRIPTION
|
|
If x and md are not relatively prime, zero is returned.
|
|
Otherwise v = minv(x, md) is the canonical residue v modulo md
|
|
for which v * x is congruent to 1 modulo md. The canonical
|
|
residues modulo md are determined as follows by md and bits 0, 2
|
|
and 4 of config("mod") (other bits are ignored).
|
|
|
|
config("mod") md > 0 md < 0
|
|
|
|
0 0 < v < md md < v < 0
|
|
1 -md < v < 0 0 < v < -md
|
|
4 0 < v < md 0 < v < -md
|
|
5 -md < v < 0 md < v < 0
|
|
16 -md/2 < v <= md/2 md/2 <= v < -md/2
|
|
17 -md/2 <= v < md/2 md/2 < v <= -md/2
|
|
20 -md/2 < v <= md/2 md/2 < v <= -md/2
|
|
21 -md/2 <= v < md/2 md/2 <= v < -md/2
|
|
|
|
EXAMPLE
|
|
; c = config("mod", 0)
|
|
; print minv(3,10), minv(-3,10), minv(3,-10), minv(-3,-10), minv(4,10)
|
|
7 3 -3 -7 0
|
|
|
|
; c = config("mod",16)
|
|
; print minv(3,10), minv(-3,10), minv(3,-10), minv(-3,-10), minv(4,10)
|
|
-3 3 -3 3 0
|
|
|
|
LIMITS
|
|
none
|
|
|
|
LINK LIBRARY
|
|
NUMBER *qminv(NUMBER *x, NUMBER *md)
|
|
|
|
SEE ALSO
|
|
mod, pmod
|
|
|
|
## Copyright (C) 1999 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: 1995/11/09 03:27:51
|
|
## File existed as early as: 1995
|
|
##
|
|
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
|
|
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
|