fix(optimizer): tolerate overspecified partition_cut

compilers/concrete-optimizer/concrete-optimizer/src/optimization/dag/multi_parameters/partition_cut.rs

@@ -182,7 +182,7 @@ impl PartitionCut {
                 _ = lut_partition.insert((input_precision, OrderedFloat(*output_norm2)));
             }
         }
-        let mut p_cut : Vec<_> = lut_partition.iter().copied().collect();
+        let mut p_cut: Vec<_> = lut_partition.iter().copied().collect();
         p_cut.sort_by(|a, b| a.partial_cmp(b).unwrap());
         _ = p_cut.pop();
         let p_cut = p_cut.iter().map(|(p, n)| (*p, n.into_inner())).collect();
@@ -192,6 +192,18 @@ impl PartitionCut {
         }
     }
 
+    pub fn delete_unused_cut(&self, used: &HashSet<PartitionIndex>) -> Self {
+        let mut p_cut = vec![];
+        for (i, &cut) in self.p_cut.iter().enumerate() {
+            if used.contains(&i) {
+                p_cut.push(cut);
+            }
+        }
+        Self {
+            p_cut,
+            rnorm2: self.rnorm2.clone(),
+        }
+    }
 }
 
 impl std::fmt::Display for PartitionCut {

compilers/concrete-optimizer/concrete-optimizer/src/optimization/dag/multi_parameters/partitionning.rs

@@ -139,6 +139,13 @@ fn resolve_by_levelled_block(
         .copied()
         .collect();
     let nb_partitions = present_partitions.len().max(1); // no tlu = no constraints
+    if p_cut.p_cut.len() + 1 != nb_partitions {
+        return resolve_by_levelled_block(
+            dag,
+            &p_cut.delete_unused_cut(&present_partitions),
+            default_partition,
+        );
+    }
     if nb_partitions == 1 {
         return only_1_partition(dag);
     }