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calc/cal/constants.cal
2017-05-21 15:38:58 -07:00

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/*
* constants - implementation of different constants to arbitrary precision
*
* Copyright (C) 2013 Christoph Zurnieden
*
* constants 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.
*
* constants 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: 30.3 $
* @(#) $Id: constants.cal,v 30.3 2013/08/11 08:41:38 chongo Exp $
* @(#) $Source: /usr/local/src/bin/calc/cal/RCS/constants.cal,v $
*
* Under source code control: 2013/08/11 01:31:28
* File existed as early as: 2013
*/
static resource_debug_level;
resource_debug_level = config("resource_debug", 0);
static __CZ__euler_mascheroni = 0;
static __CZ__euler_mascheroni_prec = 0;
define e(){
local k temp1 temp2 ret eps factor upperlimit prec;
prec = digits(1/epsilon());
if(__CZ__euler_mascheroni != 0 && __CZ__euler_mascheroni_prec >= prec)
return __CZ__euler_mascheroni;
if(prec<=20) return 2.718281828459045235360287471;
if(prec<=1800){
__CZ__euler_mascheroni = exp(1);
__CZ__euler_mascheroni_prec = prec;
}
eps=epsilon(1e-20);
factor = 1;
k = 0;
upperlimit = prec * ln(10);
while(k<upperlimit){
k += ln(factor);
factor++;
}
epsilon(eps);
temp1 = 0;
ret = 1;
for(k=3;k<=factor;k++){
temp2 = temp1;
temp1 = ret;
ret = (k-1) *(temp1 + temp2);
}
ret = inverse( ret * inverse(factorial(factor) ) ) ;
__CZ__euler_mascheroni = ret;
__CZ__euler_mascheroni_prec = prec;
return ret;
}
/* Lupas' series */
static __CZ__catalan = 0;
static __CZ__catalan_prec = 0;
define G(){
local eps a s t n;
eps = epsilon(epsilon()*1e-10);
if(__CZ__catalan != 0 && __CZ__catalan >= log(1/eps))
return __CZ__catalan;
a = 1;
s = 0;
t = 1;
n = 1;
while(abs(t)> eps){
a *= 32 * n^3 * (2*n-1);
a /=((3-16*n+16*n^2)^2);
t = a * (-1)^(n-1) * (40*n^2-24*n+3) / (n^3 * (2*n-1));
s += t;
n += 1;
}
s = s/64;
__CZ__catalan = s;
__CZ__catalan_prec = log(1/eps);
epsilon(eps);
return s;
}
config("resource_debug", resource_debug_level),;
if (config("resource_debug") & 3) {
print "e()";
print "G()";
}