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jiri 2005-09-07 20:28:03 +00:00
parent 8733f2528e
commit 19ad78d6aa
1 changed files with 37 additions and 0 deletions
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37
bisection.h
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@ -2,6 +2,7 @@
#define _BISECTION_H
//general bisection search
//returns dm-1 on failure, otherwise number between dm and hm
//cmp returns 0 on equal, >0 if first > second argument
template<typename INDEX, typename COMPAR, typename SUBJECT>
INDEX bisection_find(INDEX dm, INDEX hm, const SUBJECT *key, const SUBJECT *base , unsigned int lead_dimension_base, COMPAR (*cmp)(const SUBJECT *, const SUBJECT *))
@ -23,4 +24,40 @@ while (hm > dm+1);
return(dm0-1);
}
// interpolation search
//distance is +-0, on its quality the convergence speed depends
template<typename INDEX, typename DISTANCE, typename SUBJECT>
int interpolation_find(INDEX dm0, INDEX high, const SUBJECT *x, const SUBJECT *base , unsigned int lead_dimension_base, DISTANCE (*dist)(const SUBJECT *, const SUBJECT *))
{
INDEX low = dm0;
INDEX mid;
DISTANCE d1,d2,d3,d4;
while(1)
{
d1=(*dist)(x,base+low*lead_dimension_base);
d2=(*dist)(base+high*lead_dimension_base,x);
cout << "intlp "<<low<<" "<<high<<" "<<d1<<" "<<d2<,endl
if(d1<=0 || d2 >=0) break;
d3=(*dist)(base+high*lead_dimension_base,base+low*lead_dimension_base);
mid = low + (int)((d1 * (high-low)) / d3+.5);
d4=(*dist)(x,base+mid*lead_dimension_base);
cout << "intlp2 "<<mid<<" "<<d3<<" "<<d4<<endl;
if(d4>0)
low = mid + 1;
else if(d3<0)
high = mid - 1;
else
return mid;
}
if (d1==0) return low;
if (d2==0) return high;
return dm0-1; // Not found
}
#endif