/usr/share/calc/sumsq.cal is in apcalc-common 2.12.4.4-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | /*
* sumsq - find unique two positive integers whose squares sum to a given prime
*
* Copyright (C) 1999 David I. Bell
*
* 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.
*
* @(#) $Revision: 30.1 $
* @(#) $Id: sumsq.cal,v 30.1 2007/03/16 11:09:54 chongo Exp $
* @(#) $Source: /usr/local/src/cmd/calc/cal/RCS/sumsq.cal,v $
*
* Under source code control: 1990/02/15 01:50:37
* File existed as early as: before 1990
*
* Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
*/
/*
* Determine the unique two positive integers whose squares sum to the
* specified prime. This is always possible for all primes of the form
* 4N+1, and always impossible for primes of the form 4N-1.
*/
define ss(p)
{
local a, b, i, p4;
if (p == 2) {
print "1^2 + 1^2 = 2";
return;
}
if ((p % 4) != 1) {
print p, "is not of the form 4N+1";
return;
}
if (!ptest(p, min(p-2, 10))) {
print p, "is not a prime";
return;
}
p4 = (p - 1) / 4;
i = 2;
do {
a = pmod(i++, p4, p);
} while ((a^2 % p) == 1);
b = p;
while (b^2 > p) {
i = b % a;
b = a;
a = i;
}
print a : "^2 +" , b : "^2 =" , a^2 + b^2;
}
|