Proposed change to PPLNS rewards

[Steve Sokolowski]

We're evaluating a potential change to the PPLNS rewards system, to address customer feedback. Some customers are concerned that later shares on blocks where the pool has had poor luck can result in a lower expected profitability compared to mining in FPPS mode.


The current formula

Currently, when a block is found, the reward is distributed using the following simple formula:

Code: Select all

your_reward = (block_reward + transaction_fees) * (1.0 - pool_fee) * sum(your_share_difficulties) / sum(all_share_difficulties)

As you can see, every share is worth the same value, regardless of when it was submitted.


The proposed formula

In the proposed formula, more recent shares would be weighted so that the expected earnings from PPLNS mining are equal to those of FPPS, before the lower fees slightly increase the expected profitability. The new more complex formula for determining the value of a share would be:

Code: Select all

score = share_difficulty * 2 ^ (sum(all_share_difficulties_previously_submitted_for_this_round) / block_difficulty)
your_reward = (block_reward + transaction_fees) * (1.0 - pool_fee) * sum(your_scores) / sum(all_scores)

As you can see, when enough mining has occurred such that a block would already have been, on average, expected to have been found, each share is then worth twice as much in score as were shares submitted at the start of the round. If a block still hasn't been found after enough mining where two would normally have been expected, then the latest shares will be worth twice as much as that share, and four times as much as the first share submitted in the round.


Effect of the changes

If this change is made, a customer earns the same expected value no matter when he joins in the round, preventing new customers from being discouraged because of the significant portion of the rewards already earned by customers who had previously mined. In the new system, customers who stopped mining a while ago will still earn some money, but their proportion of the payout will decline exponentially instead of linearly.

Should we make this change?

[dalr46]

This would be a positive change to PPLNS for ProHashing, hope to see it up and running in the near future,

[thundergun]

When will this first PPLNS update happen? Will it clear out all current PPLNS amounts and reset them all?

[Sarah Manter]

The calculations of scores have already been released and verified. No, nothing has been cleared out. New scores since Friday are now in the new score system. It's all working but is just not yet displayed on the website or explained in the documentation yet. We still have a few more tasks to complete on this, but all of the back end tasks will be finished this week most likely. The website updates related to this change will take place last, as we are making some significant PPLNS improvements on the site, and it will be continually improved.

[afkluckky]

I am sure this has somthing to do with the changes to PPLNS but my payout got reset to 0 on the bitcoin pplns (which I have been on for months now). Just want to make sure that its just part of the data not displaying on the site properly yet. Thanks!

[Bringles]

My pplns for scrypt has been reset to zero as well.

[Sarah Manter]

My pplns for scrypt has been reset to zero as well.

I am sure this has somthing to do with the changes to PPLNS but my payout got reset to 0 on the bitcoin pplns (which I have been on for months now). Just want to make sure that its just part of the data not displaying on the site properly yet. Thanks!

We are looking into this issue.

[thundergun]

All of my PPLNS have been reset to Zero and are now rebuilding with lower amounts.

[Sarah Manter]

All of my PPLNS have been reset to Zero and are now rebuilding with lower amounts.

This is a known issue, and affects the displayed information only. You're being properly credited, and the engineers are looking into fixing the bug.

[thundergun]

The PPLNS amounts that had built up over time never came back, and it appears they reset again last night.
Is this still just and appearance error?

Really looking forward to the PPLNS Pro option. I like the idea of being able to be paid out not in said coin for PPLNS.