diff --git a/reCTBN/Cargo.toml b/reCTBN/Cargo.toml
index b0a691b..fdac697 100644
--- a/reCTBN/Cargo.toml
+++ b/reCTBN/Cargo.toml
@@ -13,6 +13,7 @@ bimap = "~0.6"
 enum_dispatch = "~0.3"
 statrs = "~0.16"
 rand_chacha = "~0.3"
+itertools = "~0.10"
 
 [dev-dependencies]
 approx = { package = "approx", version = "~0.5" }
diff --git a/reCTBN/src/structure_learning.rs b/reCTBN/src/structure_learning.rs
index b272e22..d119ab2 100644
--- a/reCTBN/src/structure_learning.rs
+++ b/reCTBN/src/structure_learning.rs
@@ -7,7 +7,7 @@ pub mod score_function;
 use crate::{process, tools};
 
 pub trait StructureLearningAlgorithm {
-    fn fit_transform<T>(&self, net: T, dataset: &tools::Dataset) -> T
+    fn fit_transform<T>(&mut self, net: T, dataset: &tools::Dataset) -> T
     where
         T: process::NetworkProcess;
 }
diff --git a/reCTBN/src/structure_learning/constraint_based_algorithm.rs b/reCTBN/src/structure_learning/constraint_based_algorithm.rs
index d931f78..6fd5b79 100644
--- a/reCTBN/src/structure_learning/constraint_based_algorithm.rs
+++ b/reCTBN/src/structure_learning/constraint_based_algorithm.rs
@@ -1,15 +1,18 @@
 //! Module containing constraint based algorithms like CTPC and Hiton.
 
+use itertools::Itertools;
+use std::collections::BTreeSet;
+use std::usize;
+
 use super::hypothesis_test::*;
+use crate::parameter_learning::{Cache, ParameterLearning};
 use crate::structure_learning::StructureLearningAlgorithm;
 use crate::{process, tools};
-use crate::parameter_learning::{Cache, ParameterLearning};
 
 pub struct CTPC<P: ParameterLearning> {
     Ftest: F,
     Chi2test: ChiSquare,
     cache: Cache<P>,
-
 }
 
 impl<P: ParameterLearning> CTPC<P> {
@@ -23,7 +26,7 @@ impl<P: ParameterLearning> CTPC<P> {
 }
 
 impl<P: ParameterLearning> StructureLearningAlgorithm for CTPC<P> {
-    fn fit_transform<T>(&self, net: T, dataset: &tools::Dataset) -> T
+    fn fit_transform<T>(&mut self, net: T, dataset: &tools::Dataset) -> T
     where
         T: process::NetworkProcess,
     {
@@ -34,6 +37,41 @@ impl<P: ParameterLearning> StructureLearningAlgorithm for CTPC<P> {
 
         //Make the network mutable.
         let mut net = net;
+
+        net.initialize_adj_matrix();
+
+        for child_node in net.get_node_indices() {
+            let mut candidate_parent_set: BTreeSet<usize> = net
+                .get_node_indices()
+                .into_iter()
+                .filter(|x| x != &child_node)
+                .collect();
+            let mut b = 0;
+            while b < candidate_parent_set.len() {
+                for parent_node in candidate_parent_set.iter() {
+                    for separation_set in candidate_parent_set
+                        .iter()
+                        .filter(|x| x != &parent_node)
+                        .map(|x| *x)
+                        .combinations(b)
+                    {
+                        let separation_set = separation_set.into_iter().collect();
+                        if self.Ftest.call(
+                            &net,
+                            child_node,
+                            *parent_node,
+                            &separation_set,
+                            &mut self.cache,
+                        ) && self.Chi2test.call(&net, child_node, *parent_node, &separation_set, &mut self.cache) {
+                            candidate_parent_set.remove(&parent_node);
+                            break;
+                        }
+                    }
+                }
+                b = b + 1;
+            }
+        }
+
         net
     }
 }
diff --git a/reCTBN/src/structure_learning/score_based_algorithm.rs b/reCTBN/src/structure_learning/score_based_algorithm.rs
index 16e9056..d59f0c1 100644
--- a/reCTBN/src/structure_learning/score_based_algorithm.rs
+++ b/reCTBN/src/structure_learning/score_based_algorithm.rs
@@ -21,7 +21,7 @@ impl<S: ScoreFunction> HillClimbing<S> {
 }
 
 impl<S: ScoreFunction> StructureLearningAlgorithm for HillClimbing<S> {
-    fn fit_transform<T>(&self, net: T, dataset: &tools::Dataset) -> T
+    fn fit_transform<T>(&mut self, net: T, dataset: &tools::Dataset) -> T
     where
         T: process::NetworkProcess,
     {
diff --git a/reCTBN/tests/structure_learning.rs b/reCTBN/tests/structure_learning.rs
index 6134510..4bf9027 100644
--- a/reCTBN/tests/structure_learning.rs
+++ b/reCTBN/tests/structure_learning.rs
@@ -58,7 +58,7 @@ fn simple_bic() {
     );
 }
 
-fn check_compatibility_between_dataset_and_network<T: StructureLearningAlgorithm>(sl: T) {
+fn check_compatibility_between_dataset_and_network<T: StructureLearningAlgorithm>(mut sl: T) {
     let mut net = CtbnNetwork::new();
     let n1 = net
         .add_node(generate_discrete_time_continous_node(String::from("n1"), 3))
@@ -125,7 +125,7 @@ pub fn check_compatibility_between_dataset_and_network_hill_climbing() {
     check_compatibility_between_dataset_and_network(hl);
 }
 
-fn learn_ternary_net_2_nodes<T: StructureLearningAlgorithm>(sl: T) {
+fn learn_ternary_net_2_nodes<T: StructureLearningAlgorithm>(mut sl: T) {
     let mut net = CtbnNetwork::new();
     let n1 = net
         .add_node(generate_discrete_time_continous_node(String::from("n1"), 3))
@@ -320,7 +320,7 @@ fn get_mixed_discrete_net_3_nodes_with_data() -> (CtbnNetwork, Dataset) {
     return (net, data);
 }
 
-fn learn_mixed_discrete_net_3_nodes<T: StructureLearningAlgorithm>(sl: T) {
+fn learn_mixed_discrete_net_3_nodes<T: StructureLearningAlgorithm>(mut sl: T) {
     let (net, data) = get_mixed_discrete_net_3_nodes_with_data();
     let net = sl.fit_transform(net, &data);
     assert_eq!(BTreeSet::new(), net.get_parent_set(0));
@@ -342,7 +342,7 @@ pub fn learn_mixed_discrete_net_3_nodes_hill_climbing_bic() {
     learn_mixed_discrete_net_3_nodes(hl);
 }
 
-fn learn_mixed_discrete_net_3_nodes_1_parent_constraint<T: StructureLearningAlgorithm>(sl: T) {
+fn learn_mixed_discrete_net_3_nodes_1_parent_constraint<T: StructureLearningAlgorithm>(mut sl: T) {
     let (net, data) = get_mixed_discrete_net_3_nodes_with_data();
     let net = sl.fit_transform(net, &data);
     assert_eq!(BTreeSet::new(), net.get_parent_set(0));