TnFOX: FX::QDictBase::spread

template<class keytype, class type>

void FX::QDictBase< keytype, type >::spread	(	float *	full,
		float *	slotsspread,
		float *	avrgkeysperslot,
		float *	spread
	)			const `[inline, inherited]`

Returns statistics useful for dynamic balancing of the table. If full exceeds 100%, then there are more items than slots and the table is no longer performing at maximum efficiency. If slotsspread is less than 50% then the hash function is broken. Ideally for performance purposes avrgkeysperslot should be near 1.0 and finally spread is slotsspread divided by avrgskeysperslot which is an overall indication of spread and thus efficiency of the table. Of course maximum efficiency is pointless for very large sets of data where avrgkeysperslot could be as much as eight - but slotsspread should always be near 100%

Definition at line 255 of file qdictbase.h.

Referenced by FX::QDictBase< FX::FXString, type >::statistics().

00256     {
00257         if(full) *full=(float) 100.0*items/mysize;
00258         if(slotsspread || avrgkeysperslot || spread)
00259         {
00260             FXuint slotsused=0, keys=0;
00261             for(typename dictionary::const_iterator itdict=dict.begin(); itdict!=dict.end(); ++itdict)
00262             {
00263                 const keyitemlist &kil=(*itdict);
00264                 if(!kil.empty())
00265                 {
00266                     slotsused++;
00267                     keys+=(FXuint) kil.size();
00268                 }
00269             }
00270             if(slotsspread) *slotsspread=(float) 100.0*slotsused/FXMIN(mysize, items);
00271             if(avrgkeysperslot) *avrgkeysperslot=(float) keys/slotsused;
00272             if(spread) *spread=((float) 100.0*slotsused/FXMIN(mysize, items))/((float) keys/slotsused);
00273         }
00274     }