/usr/include/liggghts/math_special.h is in libliggghts-dev 3.0.3+repack-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 66 | /* -*- c++ -*- ----------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
#ifndef LMP_MATH_SPECIAL_H
#define LMP_MATH_SPECIAL_H
#include <math.h>
namespace LAMMPS_NS {
namespace MathSpecial {
// x**2, use instead of pow(x,2.0)
static inline double square(const double &x) { return x*x; }
// x**3, use instead of pow(x,3.0)
static inline double cube(const double &x) { return x*x*x; }
// return -1.0 for odd n, 1.0 for even n, like pow(-1.0,n)
static inline double powsign(const int n) { return (n & 1) ? -1.0 : 1.0; }
// optimized version of pow(x,n) with n being integer
// up to 10x faster than pow(x,y)
static inline double powint(const double &x, const int n) {
double yy,ww;
if (x == 0.0) return 0.0;
int nn = (n > 0) ? n : -n;
ww = x;
for (yy = 1.0; nn != 0; nn >>= 1, ww *=ww)
if (nn & 1) yy *= ww;
return (n > 0) ? yy : 1.0/yy;
}
// optimized version of (sin(x)/x)**n with n being a _positive_ integer
static inline double powsinxx(const double &x, int n) {
double yy,ww;
if (x == 0.0) return 1.0;
ww = sin(x)/x;
for (yy = 1.0; n != 0; n >>= 1, ww *=ww)
if (n & 1) yy *= ww;
return yy;
}
}
}
#endif
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