/* Initialize random number generator. Note that some bytes of the "noise"
* string will have random junk in them. This is intentional. */
void init_rng() {
int a = 0;
uint8_t *noise = 0;
int64_t tstamp = 0;
pid_t pnum = 1;
noise = (uint8_t *)dw_malloc(512);
if(noise == 0) {
dw_fatal("error allocating memory for noise");
}
#ifdef VALGRIND_NOERRORS
/* Valgrind reports our intentional use of values of uncleared
* allocated memory as one source of entropy as an error, so we
* allow it to be disabled for Valgrind testing */
memset(noise,0,512);
#endif /* VALGRIND_NOERRORS */
get_entropy_from_seedfile(noise,256);
/* Get entropy from the current timestamp */
set_time();
tstamp = get_time();
for(a = 0 ; a < 8 ; a++) {
*(noise + a + 256) = tstamp & 0xff;
tstamp >>= 8;
}
/* Get entropy from the process' ID number */
pnum = getpid();
for(a = 0 ; a < sizeof(pnum) ; a++ ) {
*(noise + a + 272) = pnum & 0xff;
pnum >>= 8;
}
/* Initialize the RNG based on the contents of noise */
noise_to_rng(noise,510);
if(noise != 0) {
free(noise);
noise = 0;
}
}
TElliptical* CreateEllipticalFromPosterior_Step(TVector R, int dim, TVector center, TMatrix scale, PRECISION p_lo, PRECISION p_hi)
{
TElliptical *elliptical=(TElliptical*)NULL;
PRECISION *table, inc, x, y;
int i, j, k, m=30;
if (dim > 0)
{
table=(PRECISION*)dw_malloc((m+1)*sizeof(PRECISION));
SortVectorAscending(R,R);
for (k=m; k >= 1; k--)
{
inc=(p_hi-p_lo)/(PRECISION)k;
for (x=p_lo, j=0; j <= k; x+=inc, j++)
{
i=floor(y=x*(PRECISION)(DimV(R)-1));
if (i >= DimV(R)-1)
table[j]=ElementV(R,DimV(R)-1);
else
table[j]=(1.0-y+i)*ElementV(R,i) + (y-i)*ElementV(R,i+1);
//table[j]=(i > 0) ? 0.5*(ElementV(R,i-1) + ElementV(R,i)) : ElementV(R,i);
}
for (j=1; j <= k; j++)
if (table[j] <= table[j-1]) break;
if (j > k) break;
}
if (k <= 0)
{
dw_free(table);
printf("Not enough variation in the posterior draws to form proposal\n");
dw_exit(0);
}
elliptical=CreateElliptical_Step(dim,center,scale,table,k);
dw_free(table);
}
return elliptical;
}
