Kimoto Gravity Well Issue? - algorithm

Question

Can anybody explain what this code actually do and how it is re targeted the difficulty. I want my difficulty to be re targeted every 60 seconds, searching on internet find that this function will re targeted the difficulty.
I am working on Logos LGS coin.
unsigned int static KimotoGravityWell(const CBlockIndex* pindexLast, const CBlockHeader *pblock, uint64 TargetBlocksSpacingSeconds, uint64 PastBlocksMin, uint64 PastBlocksMax) {
/* current difficulty formula - kimoto gravity well */
const CBlockIndex *BlockLastSolved = pindexLast;
const CBlockIndex *BlockReading = pindexLast;
const CBlockHeader *BlockCreating = pblock;
BlockCreating = BlockCreating;
uint64 PastBlocksMass = 0;
int64 PastRateActualSeconds = 0;
int64 PastRateTargetSeconds = 0;
double PastRateAdjustmentRatio = double(1);
CBigNum PastDifficultyAverage;
CBigNum PastDifficultyAveragePrev;
double EventHorizonDeviation;
double EventHorizonDeviationFast;
double EventHorizonDeviationSlow;
if (BlockLastSolved == NULL || BlockLastSolved->nHeight == 0 || (uint64)BlockLastSolved->nHeight < PastBlocksMin) { return bnProofOfWorkLimit.GetCompact(); }
for (unsigned int i = 1; BlockReading && BlockReading->nHeight > 0; i++) {
if (PastBlocksMax > 0 && i > PastBlocksMax) { break; }
PastBlocksMass++;
if (i == 1) { PastDifficultyAverage.SetCompact(BlockReading->nBits); }
else { PastDifficultyAverage = ((CBigNum().SetCompact(BlockReading->nBits) - PastDifficultyAveragePrev) / i) + PastDifficultyAveragePrev; }
PastDifficultyAveragePrev = PastDifficultyAverage;
PastRateActualSeconds = BlockLastSolved->GetBlockTime() - BlockReading->GetBlockTime();
PastRateTargetSeconds = TargetBlocksSpacingSeconds * PastBlocksMass;
PastRateAdjustmentRatio = double(1);
if (PastRateActualSeconds < 0) { PastRateActualSeconds = 0; }
if (PastRateActualSeconds != 0 && PastRateTargetSeconds != 0) {
PastRateAdjustmentRatio = double(PastRateTargetSeconds) / double(PastRateActualSeconds);
}
EventHorizonDeviation = 1 + (0.7084 * pow((double(PastBlocksMass)/double(144)), -1.228));
EventHorizonDeviationFast = EventHorizonDeviation;
EventHorizonDeviationSlow = 1 / EventHorizonDeviation;
if (PastBlocksMass >= PastBlocksMin) {
if ((PastRateAdjustmentRatio <= EventHorizonDeviationSlow) || (PastRateAdjustmentRatio >= EventHorizonDeviationFast)) { assert(BlockReading); break; }
}
if (BlockReading->pprev == NULL) { assert(BlockReading); break; }
BlockReading = BlockReading->pprev;
}
CBigNum bnNew(PastDifficultyAverage);
if (PastRateActualSeconds != 0 && PastRateTargetSeconds != 0) {
bnNew *= PastRateActualSeconds;
bnNew /= PastRateTargetSeconds;
}
if (bnNew > bnProofOfWorkLimit) { bnNew = bnProofOfWorkLimit; }
return bnNew.GetCompact();
}