float wilson2_factor(int niter /* number of iterations */,
float s0 /* zero-lag auto-correlation */,
sf_filter ss /* input auto-correlation */,
float a0 /* zero-lag filter */,
sf_filter aa /* output factor */,
bool verb /* verbosity flag */,
float tol /* tolerance */)
/*< Factor >*/
{
float g0, *gg;
int i, iter;
for(i=0; i < n2; i++) {
au[i] = 0.;
}
sf_helicon_init( aa); /* multiply polynoms */
sf_polydiv_init( n2, aa); /* divide polynoms */
au[n-1] = -a0*a0;
sf_helicon_lop(false, false, n2, n2, au, bb);
sf_helicon_lop(true, false, n2, n2, au, bb);
au[n-1] += s0;
for(i=0; i < ss->nh; i++) { /* symmetrize input auto */
au[n-1+ss->lag[i]] += ss->flt[i];
au[n-1-ss->lag[i]] += ss->flt[i];
}
g0 = a0;
gg = sf_floatalloc(aa->nh);
for(i=0; i < aa->nh; i++) {
gg[i] = aa->flt[i];
}
for(iter=0; iter < niter; iter++) {
sf_polydiv_lop(false,false, n2, n2, au, bb); /* bb = S/A */
sf_polydiv_lop(true, false, n2, n2, cc, bb); /* cc = S/(AA') */
/* b = plusside(cc) */
for(i=0; i < n; i++) {
b[i] = 0.5*(cc[n-1+i] + cc[n-1-i])/a0;
}
sf_helicon_lop( false, false, n, n, b, c); /* c = A b */
a0 = 2.*(c[0]+g0);
for(i=0; i < aa->nh; i++) { /* put on helix */
aa->flt[i] = 2.*(c[aa->lag[i]]+gg[i])/a0;
}
}
a0 -= g0;
for(i=0; i < aa->nh; i++) {
aa->flt[i] = ((a0+g0)*aa->flt[i]-gg[i])/a0;
}
return a0;
}
void fixbad (int niter /* number of iterations */,
sf_filter aa /* PEF */,
int ny /* data size */,
float *yy /* in - data, out - deburst */)
/*< find bad data and restore it >*/
{
int iy;
float *rr, *rabs, rbar;
bool *known;
rr = sf_floatalloc(ny);
rabs = sf_floatalloc(ny);
known = sf_boolalloc(ny);
sf_helicon_init(aa);
sf_helicon_lop (false,false,ny,ny,yy,rr);
for (iy=0; iy < ny; iy++)
rabs[iy] = fabsf (rr[iy]);
rbar = sf_quantile(ny/2,ny,rabs);
for (iy=0; iy < ny; iy++)
known[iy] = (bool) ((yy[iy] > 0.) && (fabsf(rr[iy]) < 4. * rbar));
mis2 (niter, ny, yy, aa, known, 0., true);
free(rr);
free(rabs);
free(known);
}
void signoi_lop (bool adj, bool add, int n1, int n2,
float *data, float *sign)
/*< linear operator >*/
{
sf_helicon_init (nn);
sf_polydiv_init (nd, ss);
sf_adjnull(adj,add,n1,n2,data,sign);
sf_helicon_lop (false, false, n1, n1, data, dd);
sf_solver_prec(sf_helicon_lop, sf_cgstep, sf_polydiv_lop,
nd, nd, nd, sign, dd, niter, eps,
"verb", verb, "end");
sf_cgstep_close();
nn++;
ss++;
}
