# Slow start ramp formula? Lauch in September?

edited to answer my own question:
It looks like it’ll be linear, ramping at 0.000625 ZEC/block for 35 days or 0.0005 ZEC/block for 43 days, stopping at 12.5 ZEC/block. For example, 0.0005 ZEC/block 1st block, 0.001 ZEC/block 2nd block, etc. It will be 2.5 minutes/block, 24 blocks/hour, 576 blocks/day. About 0.3 ZEC/block at end of 1st day, 0.6 ZEC/block on 2nd day, etc. Ends at 300 ZEC/hour.

(mining slow start · Issue #762 · zcash/zcash · GitHub)

Daira:

For concreteness, assuming a 10-minute target block time, suppose we set
the slope of the ramp to be 0.01 ZEC per block. That would take 5000 *
10 minutes = 34.7 days to reach 50 ZEC. The monetary base at that point
would be 0.01*(5000*5001/2) = 125025 ZEC (as compared to 250000 ZEC if there were no slow start).

nathan-at-least: (April 11, 2016)

the halving interval remains unaltered (assuming block size/target rate
remain unchanged), so even with the slow start ramp up, the halving
interval will still remain 210,000 blocks (assuming no change to block
rate/reward). Let’s henceforth call this proposal “Slow Start Alpha”.

zookozcash:

Great work, Jack! I choose linear 5000-block ramp. Thanks everyone for
we’re planning to reduce the block interval from 10 minutes to 2.5
minutes (#764). I guess that means we should multiply by 4 all the block-count constants above?

Diara:

In that case the block reward would increase by 0.000625 ZEC per 2.5
minutes. That would take 20000 * 2.5 minutes ~= 34.7 days to reach the
maximum of 12.5 ZEC/block. The block reward of 6.25 ZEC is skipped.
Another possibility that has slightly rounder numbers for the
2.5-minute block case, is a ramp of 0.0005 ZEC per block. This takes
25000 blocks to reach the full 12.5 ZEC reward, which takes 43.4 days.

2 Likes

If ramp is 0.0005 ZEC/block:

Approximate ZEC/hour (+/- 0.3) on any given day during the ramp:
ZEC/hour = 7*day.

Approximate ZEC/day produced during a particular day after 2nd day:
ZEC/day = 160*day.

Formula for total ZEC mined after N blocks is RN(N +1)/2 where R = ramp factor such as 0.0005. For any particular day, plug in N for beginning and end of day and subtract. Day 15: 142424=8064=N1, 15=>8064+574=8640=N2. 0.0005*(N2-N1) = 2405.5 ZEC.

The slow start period is 20000 2.5-minute blocks (see https://github.com/zcash/zcash/blob/zc.v0.11.2.latest/src/chainparams.cpp#L35 ), which is ~34.7 days. The ramp is linear apart from one amount at the midpoint of the slow start period that is skipped, so the amount mined in that period is exactly half what it would otherwise have been.

1 Like