Merge pull request #1443 from opentensor/feat/reset-bonds-on-dereg

Feat/reset bonds on dereg

Author: sam0x17

pallets/subtensor/src/epoch/math.rs

@@ -549,6 +549,24 @@ pub fn inplace_mask_rows(mask: &[bool], matrix: &mut [Vec<I32F32>]) {
         });
 }
 
+// Apply column mask to matrix, mask=true will mask out, i.e. set to 0.
+// Assumes each column has the same length.
+#[allow(dead_code)]
+pub fn inplace_mask_cols(mask: &[bool], matrix: &mut [Vec<I32F32>]) {
+    let Some(first_row) = matrix.first() else {
+        return;
+    };
+    assert_eq!(mask.len(), first_row.len());
+    let zero: I32F32 = I32F32::saturating_from_num(0);
+    matrix.iter_mut().for_each(|row_elem| {
+        row_elem.iter_mut().zip(mask).for_each(|(elem, mask_col)| {
+            if *mask_col {
+                *elem = zero;
+            }
+        });
+    });
+}
+
 // Mask out the diagonal of the input matrix in-place.
 #[allow(dead_code)]
 pub fn inplace_mask_diag(matrix: &mut [Vec<I32F32>]) {
@@ -569,6 +587,26 @@ pub fn inplace_mask_diag(matrix: &mut [Vec<I32F32>]) {
     });
 }
 
+// Remove cells from sparse matrix where the mask function of a scalar and a vector is true.
+#[allow(dead_code, clippy::indexing_slicing)]
+pub fn scalar_vec_mask_sparse_matrix(
+    sparse_matrix: &[Vec<(u16, I32F32)>],
+    scalar: u64,
+    vector: &[u64],
+    mask_fn: &dyn Fn(u64, u64) -> bool,
+) -> Vec<Vec<(u16, I32F32)>> {
+    let n: usize = sparse_matrix.len();
+    let mut result: Vec<Vec<(u16, I32F32)>> = vec![vec![]; n];
+    for (i, sparse_row) in sparse_matrix.iter().enumerate() {
+        for (j, value) in sparse_row {
+            if !mask_fn(scalar, vector[*j as usize]) {
+                result[i].push((*j, *value));
+            }
+        }
+    }
+    result
+}
+
 // Mask out the diagonal of the input matrix in-place, except for the diagonal entry at except_index.
 #[allow(dead_code)]
 pub fn inplace_mask_diag_except_index(matrix: &mut [Vec<I32F32>], except_index: u16) {

pallets/subtensor/src/epoch/run_epoch.rs

@@ -22,6 +22,10 @@ impl<T: Config> Pallet<T> {
         let current_block: u64 = Self::get_current_block_as_u64();
         log::trace!("current_block:\n{:?}\n", current_block);
 
+        // Get tempo.
+        let tempo: u64 = Self::get_tempo(netuid).into();
+        log::trace!("tempo: {:?}", tempo);
+
         // Get activity cutoff.
         let activity_cutoff: u64 = Self::get_activity_cutoff(netuid) as u64;
         log::trace!("activity_cutoff:\n{:?}\n", activity_cutoff);
@@ -44,7 +48,7 @@ impl<T: Config> Pallet<T> {
         let block_at_registration: Vec<u64> = Self::get_block_at_registration(netuid);
         log::trace!("Block at registration:\n{:?}\n", &block_at_registration);
 
-        // Outdated matrix, updated_ij=True if i has last updated (weights) after j has last registered.
+        // Outdated matrix, outdated_ij=True if i has last updated (weights) after j has last registered.
         let outdated: Vec<Vec<bool>> = last_update
             .iter()
             .map(|updated| {
@@ -56,6 +60,16 @@ impl<T: Config> Pallet<T> {
             .collect();
         log::trace!("Outdated:\n{:?}\n", &outdated);
 
+        // Recently registered matrix, recently_ij=True if last_tempo was *before* j was last registered.
+        // Mask if: the last tempo block happened *before* the registration block
+        // ==> last_tempo <= registered
+        let last_tempo: u64 = current_block.saturating_sub(tempo);
+        let recently_registered: Vec<bool> = block_at_registration
+            .iter()
+            .map(|registered| last_tempo <= *registered)
+            .collect();
+        log::trace!("Recently registered:\n{:?}\n", &recently_registered);
+
         // ===========
         // == Stake ==
         // ===========
@@ -185,7 +199,8 @@ impl<T: Config> Pallet<T> {
 
         // Access network bonds.
         let mut bonds: Vec<Vec<I32F32>> = Self::get_bonds(netuid);
-        inplace_mask_matrix(&outdated, &mut bonds); // mask outdated bonds
+        // Remove bonds referring to neurons that have registered since last tempo.
+        inplace_mask_cols(&recently_registered, &mut bonds); // mask recently registered bonds
         inplace_col_normalize(&mut bonds); // sum_i b_ij = 1
         log::trace!("B:\n{:?}\n", &bonds);
 
@@ -386,6 +401,10 @@ impl<T: Config> Pallet<T> {
         let current_block: u64 = Self::get_current_block_as_u64();
         log::trace!("current_block: {:?}", current_block);
 
+        // Get tempo.
+        let tempo: u64 = Self::get_tempo(netuid).into();
+        log::trace!("tempo:\n{:?}\n", tempo);
+
         // Get activity cutoff.
         let activity_cutoff: u64 = Self::get_activity_cutoff(netuid) as u64;
         log::trace!("activity_cutoff: {:?}", activity_cutoff);
@@ -548,12 +567,15 @@ impl<T: Config> Pallet<T> {
         let mut bonds: Vec<Vec<(u16, I32F32)>> = Self::get_bonds_sparse(netuid);
         log::trace!("B: {:?}", &bonds);
 
-        // Remove bonds referring to deregistered neurons.
-        bonds = vec_mask_sparse_matrix(
+        // Remove bonds referring to neurons that have registered since last tempo.
+        // Mask if: the last tempo block happened *before* the registration block
+        // ==> last_tempo <= registered
+        let last_tempo: u64 = current_block.saturating_sub(tempo);
+        bonds = scalar_vec_mask_sparse_matrix(
             &bonds,
-            &last_update,
+            last_tempo,
             &block_at_registration,
-            &|updated, registered| updated <= registered,
+            &|last_tempo, registered| last_tempo <= registered,
         );
         log::trace!("B (outdatedmask): {:?}", &bonds);
 

pallets/subtensor/src/subnets/uids.rs

@@ -23,6 +23,7 @@ impl<T: Config> Pallet<T> {
         Consensus::<T>::mutate(netuid, |v| Self::set_element_at(v, neuron_index, 0));
         Incentive::<T>::mutate(netuid, |v| Self::set_element_at(v, neuron_index, 0));
         Dividends::<T>::mutate(netuid, |v| Self::set_element_at(v, neuron_index, 0));
+        Bonds::<T>::remove(netuid, neuron_uid); // Remove bonds for Validator.
     }
 
     /// Replace the neuron under this uid.