How To Change Retarget Difficulty For An Altcoin - c++

Question

I am helping a community of an altcoin that needs to change it's retarget difficulty. So far I have written some code for the new wallet.
This is what I have done to the main.cpp file
I want to change the retarget the difficulty from 960 blocks (1 day) to 40 blocks (1 hours) of a coin. The block that I want the change to happen is 28000.
from:
static const int64 nTargetTimespan = 1 * 24 * 60 * 60; // UFO: 1 days
static const int64 nTargetSpacing = 90; // UFO: 1.5 minute blocks
static const int64 nInterval = nTargetTimespan / nTargetSpacing;
static const int64 nReTargetHistoryFact = 4; // look at 4 times the retarget interval into block history
to:
static int64 nTargetTimespan = 1 * 24 * 60 * 60; // 1 day
static int64 nTargetSpacing = 90; // 1.5 minute blocks
static int64 nInterval = nTargetTimespan / nTargetSpacing;
static int64 nReTargetHistoryFact = 4; // look at 4 times the retarget interval into block history
Then in the GetNextWorkRequired function this:
from:
// Genesis block
if (pindexLast == NULL)
return nProofOfWorkLimit;
// Only change once per interval
if ((pindexLast->nHeight+1) % nInterval != 0)
to:
// Genesis block
if (pindexLast == NULL)
return nProofOfWorkLimit;
// From block 28000 reassess the difficulty every 40 blocks
// Reduce Retarget factor to 2
if(pindexLast->nHeight >= 28000)
{
nTargetTimespan = 60 * 60; // 1 hours
nTargetSpacing = 1.5 * 60; // 1.5 minutes
nInterval = nTargetTimespan / nTargetSpacing;
nReTargetHistoryFact = 2;
}
else
{
nTargetTimespan = 1 * 24 * 60 * 60; // 1 day
nTargetSpacing = 1.5 * 60; // 1.5 minutes
nInterval = nTargetTimespan / nTargetSpacing;
nReTargetHistoryFact = 4;
}
// Only change once per interval
if ((pindexLast->nHeight+1) % nInterval != 0)
Is this code correct or is something else to be done?
Thanks I appreciate any help.

Answer 1

your code looks good. I was wondering the same, so i changed it as you did , but i got this error
GetNextWorkRequired RETARGET
nTargetTimespan = 60 nActualTimespan = 79
Before: 1d0d7333 0000000d73330000000000000000000000000000000000000000000000000000
After: 1d11b58b 00000011b58baeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
ERROR: AcceptBlock() : incorrect proof of work
ERROR: ProcessBlock() : AcceptBlock FAILED
I don't know if it could work if i release the new wallet