Fip0081 gradual activation

FIPS/fip-0081.md

@@ -77,27 +77,72 @@ but an undesirable property of tending network collateral to zero as the baselin
 This proposal aims to maintain the desirable property of exponential pledge decrease but introduces
 a reasonable lower bound on network collateral.
 
+
 ## Specification
-Factor the per-sector initial consensus pledge into two parts: a 70% share which divides by the baseline function like today,
-and a smaller 30% "simple" share which does not divide by the baseline function.
+Factor the `SectorInitialConsensusPledge` pledge into two parts, the `SimpleConsensusPledge` and the `BaselineConsensusPledge`, defined as follows:
+
+```
+BaselineConsensusPledge = PledgeLockTarget * SectorQAP / max(NetworkBaseline, NetworkQAP)
+SimpleConsensusPledge = PledgeLockTarget * SectorQAP / max(NetworkBaseline)
+
+PledgeLockTarget = 0.3 * CirculatingSupply
+```
+
+A convex combination of `SimpleConsensusPledge` and `BaselineConsensusPledge` is now the `SectorInitialConsensusPledge`, with a parameter `gamma` which controls the contribution of each component of pledge to the overall `SectorInitialConsensusPledge`.  The new definition is:
 
 ```
-SectorInitialConsensusPledge = PledgeLockTarget * (0.3 * SectorSimpleShare + 0.7 * SectorBaselineShare) 
+SectorInitialConsensusPledge = (1-gamma)*SimpleConsensusPledge + gamma*BaselineConsensusPledge
+```
+
+To achieve a ramped activation, vary the gamma parameter linearly from 1.0 at the date of activation to 0.7, on the date when the ramped activation will be completed.  
+
+![ramped_activation_gamma.png](../resources/fip-0081/ramped_activation_gamma.png)
+
+<!-- Factor the per-sector initial consensus pledge into two parts: a 70% share which divides by the baseline function like today,
+and a smaller 30% "simple" share which does not divide by the baseline function.  Gradually activate the change from the current
+to the target over the activation period - the time window over which the gamma value is varied, by adding a new parameter, gamma, which varies from the initial value of 1.0 at the start of the activation decreases linearly to a value of 0.7 at the end of the ramped activation period.
+
+```
+FIP_activation_date = # TBD
+activation_len_days = int(365)
+current_day = 0
+update_day = (FIP_activation_date - datetime.today()).days
+state = "before_activation"
+while True:
+    if state == "before_activation":
+        gamma_day = 1
+        if current_day >= update_day:
+            state = "ramping"
+    elif state == "ramping":
+        gamma_day -= 0.3/(activation_len_days-1)
+        if current_day >= (update_day + activation_len_days - 1):
+            state = "after_ramping"
+    elif state == "after_ramping":
+        gamma_day = 0.7
+    SectorInitialConsensusPledge_day = PledgeLockTarget * ( ((1-gamma_day)*SectorSimpleShare) + (gamma_day*SectorBaselineShare) )
+    current_day += 1
 
 SectorSimpleShare = SectorQAP / NetworkQAP
 SectorBaselineShare = SectorQAP / max(NetworkBaseline, NetworkQAP)
 PledgeLockTarget = 0.3 * CirculatingSupply
-```
+``` -->
 
 Note that the implemented calculation should be re-arranged to defer division until the final operations,
 to avoid loss of precision in rounding.
 
 The practical effect of this is that the sector initial pledge calculation will not tend to zero
 as the network baseline grows, 
-but toward the SectorSimpleShare (30% of the pre-baseline-crossing total).
+but toward the `SectorInitialConsensusPledge` (30% of the pre-baseline-crossing total).
 When/if the baseline function exceeds network QAP, the per-sector initial pledge value will still decrease exponentially,
 but to this floor rather than toward zero.
 
+### Motivation for Ramped Activation
+The proposed update for `SectorInitialConsensusPledge` requires setting the gamma parameter to 0.7, which results in 70% of the `SectorInitialConsensusPledge` coming from `BaselineConsensusPledge`, and 30% coming from `SimpleConsensusPledge`. 
+
+Under the updated formula for `SectorInitialConsensusPledge`, the network's current setting is `gamma=1.0`, which results in all of the `SectorInitialConsensusPledge` coming from `BaselineConsensusPledge`.
+
+We recommend updating gamma from its current value of 1.0 to the target value of 0.7 over an period of 1Y. The technical reason for this recommendation is that gamma has a direct effect on pledge - changing this gradually will prevent pledge from sharply increasing, which will negatively affect SPs. There are additional economic considerations which support this recommendation and are discussed [here](../resources/fip-0081/gradual_activation_rationale.pdf).
+
 ## Design Rationale
 
 The baseline function primarily exists to mediate the minting of rewards.
@@ -236,9 +281,5 @@ so the supply of storage is more than adequate to demand.
 
 To be provided.
 
-## TODO
-
-- Implementation
-
 ## Copyright
 Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).