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* Source sampling routines |
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*/ |
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#include "standard.h" |
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#include "ray.h" |
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#include "object.h" |
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#include "source.h" |
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#include "random.h" |
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extern int dimlist[]; /* dimension list for distribution */ |
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extern int ndims; /* number of dimensions so far */ |
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extern int samplendx; /* index for this sample */ |
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static int cyl_partit(), flt_partit(); |
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double |
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nextssamp(org, dir, si) /* compute sample for source, rtn. distance */ |
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FVECT org, dir; /* origin is read only, direction is set */ |
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nextssamp(r, si) /* compute sample for source, rtn. distance */ |
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register RAY *r; /* origin is read, direction is set */ |
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register SRCINDEX *si; /* source index (modified to current) */ |
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{ |
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int cent[3], size[3], parr[2]; |
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FVECT vpos; |
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double d; |
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register int i; |
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tryagain: |
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nextsample: |
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while (++si->sp >= si->np) { /* get next sample */ |
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if (++si->sn >= nsources) |
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return(0.0); /* no more */ |
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if (srcsizerat <= FTINY) |
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nopart(si, org); |
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if (source[si->sn].sflags & SSKIP) |
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si->np = 0; |
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else if (srcsizerat <= FTINY) |
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nopart(si, r); |
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else { |
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for (i = si->sn; source[i].sflags & SVIRTUAL; |
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i = source[i].sa.sv.sn) |
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; /* partition source */ |
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(*sfun[source[i].so->otype].of->partit)(si, org); |
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(*sfun[source[i].so->otype].of->partit)(si, r); |
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} |
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si->sp = -1; |
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} |
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vpos[i] += (double)cent[i]/MAXSPART; |
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/* compute direction */ |
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for (i = 0; i < 3; i++) |
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dir[i] = source[si->sn].sloc[i] + |
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r->rdir[i] = source[si->sn].sloc[i] + |
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vpos[SU]*source[si->sn].ss[SU][i] + |
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vpos[SV]*source[si->sn].ss[SV][i] + |
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vpos[SW]*source[si->sn].ss[SW][i]; |
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if (!(source[si->sn].sflags & SDISTANT)) |
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for (i = 0; i < 3; i++) |
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dir[i] -= org[i]; |
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r->rdir[i] -= r->rorg[i]; |
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/* compute distance */ |
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if ((d = normalize(dir)) == 0.0) |
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goto tryagain; /* at source! */ |
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if ((d = normalize(r->rdir)) == 0.0) |
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goto nextsample; /* at source! */ |
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/* compute sample size */ |
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si->dom = source[si->sn].ss2; |
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if (source[si->sn].sflags & SFLAT) { |
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si->dom *= sflatform(si->sn, dir); |
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if (si->dom <= FTINY) { /* behind source */ |
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si->np = 0; |
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goto tryagain; |
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} |
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si->dom *= (double)(size[SU]*size[SV])/(MAXSPART*MAXSPART); |
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si->dom *= sflatform(si->sn, r->rdir); |
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si->dom *= size[SU]*size[SV]/(MAXSPART*(double)MAXSPART); |
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} else if (source[si->sn].sflags & SCYL) { |
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si->dom *= scylform(si->sn, dir); |
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si->dom *= (double)size[SU]/MAXSPART; |
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si->dom *= scylform(si->sn, r->rdir); |
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si->dom *= size[SU]/(double)MAXSPART; |
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} else { |
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si->dom *= (double)(size[SU]*size[SV]*size[SW]) / |
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(MAXSPART*MAXSPART*MAXSPART) ; |
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si->dom *= size[SU]*size[SV]*(double)size[SW] / |
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(MAXSPART*MAXSPART*(double)MAXSPART) ; |
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} |
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if (source[si->sn].sflags & SDISTANT) |
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return(FHUGE); |
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if (si->dom <= 1e-4) |
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goto nextsample; /* behind source? */ |
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si->dom /= d*d; |
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return(d); /* sample OK, return distance */ |
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} |
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} |
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nopart(si, ro) /* single source partition */ |
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nopart(si, r) /* single source partition */ |
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register SRCINDEX *si; |
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FVECT ro; |
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RAY *r; |
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{ |
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clrpart(si->spt); |
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setpart(si->spt, 0, S0); |
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} |
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cylpart(si, ro) /* partition a cylinder */ |
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cylpart(si, r) /* partition a cylinder */ |
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SRCINDEX *si; |
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FVECT ro; |
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register RAY *r; |
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{ |
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double dist2, safedist2, dist2cent, rad2; |
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FVECT v; |
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int pi; |
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/* first check point location */ |
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clrpart(si->spt); |
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sp = &source[si->sn]; |
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sp = source + si->sn; |
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rad2 = 1.365 * DOT(sp->ss[SV],sp->ss[SV]); |
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v[0] = ro[0] - sp->sloc[0]; |
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v[1] = ro[1] - sp->sloc[1]; |
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v[2] = ro[2] - sp->sloc[2]; |
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v[0] = r->rorg[0] - sp->sloc[0]; |
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v[1] = r->rorg[1] - sp->sloc[1]; |
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v[2] = r->rorg[2] - sp->sloc[2]; |
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dist2 = DOT(v,sp->ss[SU]); |
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safedist2 = DOT(sp->ss[SU],sp->ss[SU]); |
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dist2 *= dist2 / safedist2; |
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si->np = 0; |
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return; |
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} |
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safedist2 *= 4./(srcsizerat*srcsizerat); |
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if (dist2 <= 4.*rad2 || /* point too close to subdivide? */ |
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dist2cent >= safedist2) { |
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safedist2 *= 4.*r->rweight*r->rweight/(srcsizerat*srcsizerat); |
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if (dist2 <= 4.*rad2 || /* point too close to subdivide */ |
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dist2cent >= safedist2) { /* or too far */ |
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setpart(si->spt, 0, S0); |
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si->np = 1; |
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return; |
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} |
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pi = 0; |
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si->np = cyl_partit(ro, si->spt, &pi, MAXSPART, |
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si->np = cyl_partit(r->rorg, si->spt, &pi, MAXSPART, |
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sp->sloc, sp->ss[SU], safedist2); |
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} |
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} |
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flatpart(si, ro) /* partition a flat source */ |
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flatpart(si, r) /* partition a flat source */ |
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register SRCINDEX *si; |
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< |
FVECT ro; |
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> |
register RAY *r; |
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{ |
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< |
register double *vp; |
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> |
register FLOAT *vp; |
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> |
FVECT v; |
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double du2, dv2; |
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int pi; |
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clrpart(si->spt); |
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vp = source[si->sn].sloc; |
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v[0] = r->rorg[0] - vp[0]; |
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v[1] = r->rorg[1] - vp[1]; |
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v[2] = r->rorg[2] - vp[2]; |
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vp = source[si->sn].snorm; |
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if (DOT(v,vp) <= FTINY) { /* behind source */ |
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si->np = 0; |
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return; |
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} |
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dv2 = 2.*r->rweight/srcsizerat; |
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dv2 *= dv2; |
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vp = source[si->sn].ss[SU]; |
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< |
du2 = 4./(srcsizerat*srcsizerat) * DOT(vp,vp); |
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> |
du2 = dv2 * DOT(vp,vp); |
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vp = source[si->sn].ss[SV]; |
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< |
dv2 = 4./(srcsizerat*srcsizerat) * DOT(vp,vp); |
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< |
clrpart(si->spt); |
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dv2 *= DOT(vp,vp); |
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pi = 0; |
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< |
si->np = flt_partit(ro, si->spt, &pi, MAXSPART, source[si->sn].sloc, |
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> |
si->np = flt_partit(r->rorg, si->spt, &pi, MAXSPART, |
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> |
source[si->sn].sloc, |
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source[si->sn].ss[SU], source[si->sn].ss[SV], du2, dv2); |
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} |
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int sn; |
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register FVECT dir; /* assume normalized */ |
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{ |
310 |
< |
register double *dv; |
310 |
> |
register FLOAT *dv; |
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double d; |
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dv = source[sn].ss[SU]; |