Fix error with iterators

Author: tsmbland

src/simulation/optimisation.rs

@@ -267,10 +267,12 @@ impl Solution<'_> {
     pub fn iter_activity_keys_for_existing(
         &self,
     ) -> impl Iterator<Item = (&AssetRef, &TimeSliceID)> {
+        let cols = &self.solution.columns()[self.variables.existing_asset_var_idx.clone()];
         self.variables
             .activity_var_keys()
             .skip(self.variables.existing_asset_var_idx.start)
-            .map(|(asset, time_slice)| (asset, time_slice))
+            .zip(cols.iter())
+            .map(|((asset, time_slice), _)| (asset, time_slice))
     }
 
     /// Activity for each candidate asset
@@ -289,10 +291,12 @@ impl Solution<'_> {
     pub fn iter_activity_keys_for_candidates(
         &self,
     ) -> impl Iterator<Item = (&AssetRef, &TimeSliceID)> {
+        let cols = &self.solution.columns()[self.variables.candidate_asset_var_idx.clone()];
         self.variables
             .activity_var_keys()
             .skip(self.variables.candidate_asset_var_idx.start)
-            .map(|(asset, time_slice)| (asset, time_slice))
+            .zip(cols.iter())
+            .map(|((asset, time_slice), _)| (asset, time_slice))
     }
 
     /// Iterate over unmet demand