static int
MATGEN(REAL a[], int lda, int n, REAL b[], REAL *norma)
{
int i;
int init[4];
int j;
REAL value;
init[0] = 1;
init[1] = 2;
init[2] = 3;
init[3] = 1325;
*norma = LP_ZERO;
for (j = 0; j < n; j++) {
for (i = 0; i < n; i++) {
#ifdef FPS_LAPA_UNK
a[lda*j+i] =
(i < j) ? (double)(i+1) : (double)(j+ALPHA);
if (fabs(a[lda*j+i]) > *norma)
*norma = fabs(a[lda*j+i]);
} /* i */
#else
value = (REAL) dran(init) - 0.5;
a[lda * j + i] = value;
value = fabs(value);
if (value > *norma) {
*norma = value;
}
} /* i */
#endif /* FPS_LAPA_UNK */
} /* j */
void pos_from_monte_carlo(int n,double step, Vec *L, double t, Vec* pos)
{
int i,j;
Vec spos,dist;
double dU;
double chProb,Udiff;
//printf("pos3! %.3f\n", pos[3].x);
for(i=0; i<n; i++) {
spos.x = inrange(pos[i].x + dran_sign()*step,L->x);
spos.y = inrange(pos[i].y + dran_sign()*step,L->y);
dU = 0.0;
for(j=0; j<n; j++)
if(i!=j)
dU += pair_interaction(dist2(L, &spos, pos+j, &dist)) - pair_interaction(dist2(L, pos+i, pos+j, &dist));
chProb = fmin(1,exp(-dU/t));
if(dran() < chProb) {
pos[i].x = spos.x;
pos[i].y = spos.y;
}
}
}
void pos_from_monte_carlo(int n,double step, Vec *L, double t, double noise, double alpha, double deltat, Vec* pos, Vec* force)
{
int i,j;
Vec spos,dist;
double Ur,Ui;
double chProb,Udiff;
for(i=0; i<n; i++) {
spos.x = pos[i].x + dran_sign()*step;
spos.y = pos[i].y + dran_sign()*step;
Ur = Ui = 0.0;
for(j=0; j<n; j++) {
Ur += pair_interaction(dist2(L, pos+i, pos+j, &dist));
Ui += pair_interaction(dist2(L, &spos, pos+j, &dist));
}
Udiff = Ui-Ur;
chProb = fmin(1,exp(-Udiff/t));
if(dran() < chProb) {
pos[i].x = spos.x;
pos[i].y = spos.x;
}
}
}
