MD-Bench/lammps/util.c
Rafael Ravedutti 9ffc09f497 Add DEM kernel to parameter options
Signed-off-by: Rafael Ravedutti <rafaelravedutti@gmail.com>
2022-07-07 00:47:38 +02:00

98 lines
2.5 KiB
C

/*
* =======================================================================================
*
* Author: Jan Eitzinger (je), jan.eitzinger@fau.de
* Copyright (c) 2020 RRZE, University Erlangen-Nuremberg
*
* This file is part of MD-Bench.
*
* MD-Bench is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* MD-Bench 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.
*
* You should have received a copy of the GNU Lesser General Public License along
* with MD-Bench. If not, see <https://www.gnu.org/licenses/>.
* =======================================================================================
*/
#include <string.h>
#include <util.h>
/* Park/Miller RNG w/out MASKING, so as to be like f90s version */
#define IA 16807
#define IM 2147483647
#define AM (1.0/IM)
#define IQ 127773
#define IR 2836
#define MASK 123459876
double myrandom(int* seed)
{
int k= (*seed) / IQ;
double ans;
*seed = IA * (*seed - k * IQ) - IR * k;
if(*seed < 0) *seed += IM;
ans = AM * (*seed);
return ans;
}
void random_reset(int *seed, int ibase, double *coord)
{
int i;
char *str = (char *) &ibase;
int n = sizeof(int);
unsigned int hash = 0;
for (i = 0; i < n; i++) {
hash += str[i];
hash += (hash << 10);
hash ^= (hash >> 6);
}
str = (char *) coord;
n = 3 * sizeof(double);
for (i = 0; i < n; i++) {
hash += str[i];
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
// keep 31 bits of unsigned int as new seed
// do not allow seed = 0, since will cause hang in gaussian()
*seed = hash & 0x7ffffff;
if (!(*seed)) *seed = 1;
// warm up the RNG
for (i = 0; i < 5; i++) myrandom(seed);
//save = 0;
}
int str2ff(const char *string)
{
if(strncmp(string, "lj", 2) == 0) return FF_LJ;
if(strncmp(string, "eam", 3) == 0) return FF_EAM;
if(strncmp(string, "dem", 3) == 0) return FF_DEM;
return -1;
}
const char* ff2str(int ff)
{
if(ff == FF_LJ) { return "lj"; }
if(ff == FF_EAM) { return "eam"; }
if(ff == FF_DEM) { return "dem"; }
return "invalid";
}