Re: [ANN][DRK] DarkCoin | First Anonymous Coin | First X11 | First DGW

Quote from: dime on May 17, 2014, 01:17:03 PM

2. DGW is another correction of something that already exists. It's just a rebalance of something that was not fast enough at what it was doing. I can't be sure on this point because I haven't bothered to read the code yet, but I suspect this is true.

DGW is not based on anything. I used the same strategies used in financial modeling to model the difficulty and provide a good fit.

Code:

unsigned int static DarkGravityWave3(const CBlockIndex* pindexLast, const CBlockHeader *pblock) {
   /* current difficulty formula, darkcoin - DarkGravity v3, written by Evan Duffield - evan@darkcoin.io */
   const CBlockIndex *BlockLastSolved = pindexLast;
   const CBlockIndex *BlockReading = pindexLast;
   const CBlockHeader *BlockCreating = pblock;
   BlockCreating = BlockCreating;
   int64 nActualTimespan = 0;
   int64 LastBlockTime = 0;
   int64 PastBlocksMin = 24;
   int64 PastBlocksMax = 24;
   int64 CountBlocks = 0;
   CBigNum PastDifficultyAverage;
   CBigNum PastDifficultyAveragePrev;

   if (BlockLastSolved == NULL || BlockLastSolved->nHeight == 0 || BlockLastSolved->nHeight < PastBlocksMin) {
   return bnProofOfWorkLimit.GetCompact();
   }

   for (unsigned int i = 1; BlockReading && BlockReading->nHeight > 0; i++) {
   if (PastBlocksMax > 0 && i > PastBlocksMax) { break; }
   CountBlocks++;

   if(CountBlocks <= PastBlocksMin) {
   if (CountBlocks == 1) { PastDifficultyAverage.SetCompact(BlockReading->nBits); }
   else { PastDifficultyAverage = ((PastDifficultyAveragePrev * CountBlocks)+(CBigNum().SetCompact(BlockReading->nBits))) / (CountBlocks+1); }
   PastDifficultyAveragePrev = PastDifficultyAverage;
   }

   if(LastBlockTime > 0){
   int64 Diff = (LastBlockTime - BlockReading->GetBlockTime());
   nActualTimespan += Diff;
   }
   LastBlockTime = BlockReading->GetBlockTime();

   if (BlockReading->pprev == NULL) { assert(BlockReading); break; }
   BlockReading = BlockReading->pprev;
   }

   CBigNum bnNew(PastDifficultyAverage);

   int64 nTargetTimespan = CountBlocks*nTargetSpacing;

   if (nActualTimespan < nTargetTimespan/3)
   nActualTimespan = nTargetTimespan/3;
   if (nActualTimespan > nTargetTimespan*3)
   nActualTimespan = nTargetTimespan*3;

   // Retarget
   bnNew *= nActualTimespan;
   bnNew /= nTargetTimespan;

   if (bnNew > bnProofOfWorkLimit){
   bnNew = bnProofOfWorkLimit;
   }

   return bnNew.GetCompact();
}