83 lines
2.6 KiB
C++
83 lines
2.6 KiB
C++
/*
|
|
LA: linear algebra C++ interface library
|
|
Copyright (C) 2008 Jiri Pittner <jiri.pittner@jh-inst.cas.cz> or <jiri@pittnerovi.com>
|
|
|
|
This program is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#ifndef _BISECTION_H
|
|
#define _BISECTION_H
|
|
|
|
namespace LA {
|
|
|
|
//general bisection search between dm and hm
|
|
//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 *))
|
|
{
|
|
if(dm>hm) return(dm-1);
|
|
if(dm==hm) return (*cmp)(base+dm*lead_dimension_base,key)? dm-1 :dm;
|
|
INDEX sm;
|
|
INDEX dm0=dm;
|
|
--dm;
|
|
++hm;
|
|
do
|
|
{
|
|
sm = (dm+hm)/2;
|
|
COMPAR q = (*cmp)(base+sm*lead_dimension_base,key);
|
|
if (!q) return(sm);
|
|
else if (q<0) dm = sm; else hm = sm;
|
|
}
|
|
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);
|
|
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);
|
|
if(mid<low||mid>high) laerror("interpolation_find: error in distance function");
|
|
d4=(*dist)(x,base+mid*lead_dimension_base);
|
|
if(d4>0)
|
|
low = mid + 1;
|
|
else if(d4<0)
|
|
high = mid - 1;
|
|
else
|
|
return mid;
|
|
}
|
|
|
|
if (d1==0) return low;
|
|
if (d2==0) return high;
|
|
return dm0-1; // Not found
|
|
}
|
|
|
|
|
|
}//namespace
|
|
#endif
|