diff --git a/.vscode/settings.json b/.vscode/settings.json
deleted file mode 100644
index 7a73a41b..00000000
--- a/.vscode/settings.json
+++ /dev/null
@@ -1,2 +0,0 @@
-{
-}
\ No newline at end of file
diff --git a/Cargo.toml b/Cargo.toml
index b5f68995..143e7f24 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,4 +3,4 @@
 members = [
     "smt-log-parser",
     "axiom-profiler-GUI",
-]
\ No newline at end of file
+]
diff --git a/axiom-profiler-GUI/.cargo/config.toml b/axiom-profiler-GUI/.cargo/config.toml
deleted file mode 100644
index e69de29b..00000000
diff --git a/smt-log-parser/.cargo/config.toml b/smt-log-parser/.cargo/config.toml
deleted file mode 100644
index 2a3d8f84..00000000
--- a/smt-log-parser/.cargo/config.toml
+++ /dev/null
@@ -1 +0,0 @@
-[build]
\ No newline at end of file
diff --git a/smt-log-parser/Cargo.toml b/smt-log-parser/Cargo.toml
index 324816d2..04faddd6 100644
--- a/smt-log-parser/Cargo.toml
+++ b/smt-log-parser/Cargo.toml
@@ -18,4 +18,4 @@ typed-index-collections = { version = "3.1", features = ["serde"] }
 fxhash = "0.2"
 duplicate = "1.0"
 gloo-console = "0.3.0"
-fixedbitset = "0.4.2"
+roaring = "0.10"
diff --git a/smt-log-parser/src/parsers/z3/inst_graph.rs b/smt-log-parser/src/parsers/z3/inst_graph.rs
index 5ef69bf9..4790df6d 100644
--- a/smt-log-parser/src/parsers/z3/inst_graph.rs
+++ b/smt-log-parser/src/parsers/z3/inst_graph.rs
@@ -10,7 +10,7 @@ use petgraph::{
 };
 use petgraph::{Direction, Graph};
 use std::fmt;
-use fixedbitset::FixedBitSet;
+use roaring::bitmap::RoaringBitmap;
 
 use crate::items::{BlamedTermItem, InstIdx, QuantIdx, TermIdx, DepType, Dependency};
 
@@ -95,7 +95,7 @@ pub struct InstGraph {
     node_of_line_nr: FxHashMap<usize, NodeIndex>, // line number => node-index
     cost_ranked_node_indices: Vec<NodeIndex>,
     branching_ranked_node_indices: Vec<NodeIndex>,
-    tr_closure: Vec<FixedBitSet>,
+    tr_closure: Vec<RoaringBitmap>,
 }
 
 enum InstOrder {
@@ -225,7 +225,7 @@ impl InstGraph {
     fn tr_closure_contains_edge(&self, from: NodeIndex, to: NodeIndex) -> bool {
         let topo_ord_from = self.orig_graph.node_weight(from).unwrap().topo_ord;
         let from_bitset = &self.tr_closure[topo_ord_from];
-        from_bitset.contains(to.index())
+        from_bitset.contains(to.index() as u32)
     }
 
     pub fn keep_n_most_costly(&mut self, n: usize) {
@@ -625,7 +625,7 @@ impl InstGraph {
             }
         }
         log!("Building fixedbitsets");
-        self.tr_closure = vec![FixedBitSet::with_capacity(self.orig_graph.node_count()); self.orig_graph.node_count()];
+        self.tr_closure = vec![RoaringBitmap::new(); self.orig_graph.node_count()];
         // note that we are storing the FixedBitSet's of each node index in topological order!
         log!("Computing transitive closure");
         let mut topo = Topo::new(petgraph::visit::Reversed(&self.orig_graph));
@@ -634,12 +634,12 @@ impl InstGraph {
         while let Some((last, others)) = bitsets.split_last_mut() {
             if let Some(nx) = topo.next(petgraph::visit::Reversed(&self.orig_graph)) {
                 // log!(format!("Visiting node {} with topo ord {} to compute bitset", nx.index(), ord));
-                last.set(nx.index(), true);
+                last.insert(nx.index() as u32);
                 for pred in self.orig_graph.neighbors_directed(nx, Incoming) {
                     // log!(format!("Visiting predecessor {} of node {} to compute bitset", pred.index(), nx.index()));
                     let pred_topo_ord = self.orig_graph.node_weight(pred).unwrap().topo_ord;
                     let pred_bitset = others.get_mut(pred_topo_ord).unwrap();
-                    pred_bitset.union_with(last);
+                    *pred_bitset |= &*last;
                     // log!(format!("The bitset of pred {} with topo ord {} is {}", pred.index(), pred_topo_ord, pred_bitset));
                 }
                 // log!(format!("After for loop of node {}", nx.index()));