Change update_moving_price() function

- change the function to use FirstEmissionBlockNumber parameter instead of NetworkRegisteredAt.

Author: shamil-gadelshin

Diff for: pallets/subtensor/src/staking/stake_utils.rs

@@ -58,18 +58,24 @@ impl<T: Config> Pallet<T> {
         }
     }
     pub fn update_moving_price(netuid: u16) {
-        let blocks_since_registration = U96F32::saturating_from_num(
-            Self::get_current_block_as_u64().saturating_sub(NetworkRegisteredAt::<T>::get(netuid)),
-        );
+        let blocks_since_start_call = U96F32::saturating_from_num({
+            // We expect FirstEmissionBlockNumber to be set earlier, and we take the block when
+            // `start_call` was called (first block before FirstEmissionBlockNumber).
+            let start_call_block = FirstEmissionBlockNumber::<T>::get(netuid)
+                .unwrap_or_default()
+                .saturating_sub(1);
+
+            Self::get_current_block_as_u64().saturating_sub(start_call_block)
+        });
 
         // Use halving time hyperparameter. The meaning of this parameter can be best explained under
         // the assumption of a constant price and SubnetMovingAlpha == 0.5: It is how many blocks it
         // will take in order for the distance between current EMA of price and current price to shorten
         // by half.
         let halving_time = EMAPriceHalvingBlocks::<T>::get(netuid);
         let current_ma_unsigned = U96F32::saturating_from_num(SubnetMovingAlpha::<T>::get());
-        let alpha: U96F32 = current_ma_unsigned.saturating_mul(blocks_since_registration.safe_div(
-            blocks_since_registration.saturating_add(U96F32::saturating_from_num(halving_time)),
+        let alpha: U96F32 = current_ma_unsigned.saturating_mul(blocks_since_start_call.safe_div(
+            blocks_since_start_call.saturating_add(U96F32::saturating_from_num(halving_time)),
         ));
         // Because alpha = b / (b + h), where b and h > 0, alpha < 1, so 1 - alpha > 0.
         // We can use unsigned type here: U96F32

Diff for: pallets/subtensor/src/tests/coinbase.rs

@@ -190,7 +190,7 @@ fn test_coinbase_moving_prices() {
         SubnetAlphaIn::<Test>::insert(netuid, 1_000_000);
         SubnetMechanism::<Test>::insert(netuid, 1);
         SubnetMovingPrice::<Test>::insert(netuid, I96F32::from_num(1));
-        NetworkRegisteredAt::<Test>::insert(netuid, 1);
+        FirstEmissionBlockNumber::<Test>::insert(netuid, 1);
 
         // Updating the moving price keeps it the same.
         assert_eq!(
@@ -250,7 +250,7 @@ fn test_update_moving_price_initial() {
 
         // Registered recently
         System::set_block_number(510);
-        NetworkRegisteredAt::<Test>::insert(netuid, 500);
+        FirstEmissionBlockNumber::<Test>::insert(netuid, 500);
 
         SubtensorModule::update_moving_price(netuid);
 
@@ -275,7 +275,7 @@ fn test_update_moving_price_after_time() {
 
         // Registered long time ago
         System::set_block_number(144_000_500);
-        NetworkRegisteredAt::<Test>::insert(netuid, 500);
+        FirstEmissionBlockNumber::<Test>::insert(netuid, 500);
 
         SubtensorModule::update_moving_price(netuid);