Added MLE

src/ctbn.rs

@@ -97,6 +97,10 @@ impl network::Network for CtbnNetwork {
         0..self.nodes.len()
     }
 
+    fn get_number_of_nodes(&self) -> usize {
+        self.nodes.len()
+    }
+
     fn get_node(&self, node_idx: usize) -> &node::Node{
         &self.nodes[node_idx]
     }
@@ -117,6 +121,15 @@ impl network::Network for CtbnNetwork {
         }).0
     }
 
+
+    fn get_param_index_from_custom_parent_set(&self, current_state: &Vec<StateType>, parent_set: &BTreeSet<usize>) -> usize {
+        parent_set.iter().fold((0, 1), |mut acc, x| {
+            acc.0 += self.nodes[*x].params.state_to_index(&current_state[*x]) * acc.1;
+            acc.1 *= self.nodes[*x].params.get_reserved_space_as_parent();
+            acc
+        }).0
+    }
+
     fn get_parent_set(&self, node: usize) -> BTreeSet<usize> {
         self.adj_matrix.as_ref()
             .unwrap()
@@ -229,5 +242,32 @@ mod tests {
                                               params::StateType::Discrete(1), 
                                               params::StateType::Discrete(0)]);
         assert_eq!(1, idx);
+
+    }
+
+
+
+    #[test]
+    fn compute_index_from_custom_parent_set() {
+        let mut net = CtbnNetwork::init();
+        let n1 = net.add_node(define_binary_node(String::from("n1"))).unwrap();
+        let n2 = net.add_node(define_binary_node(String::from("n2"))).unwrap();
+        let n3 = net.add_node(define_binary_node(String::from("n3"))).unwrap();
+
+
+        let idx = net.get_param_index_from_custom_parent_set(&vec![
+                                              params::StateType::Discrete(0), 
+                                              params::StateType::Discrete(0), 
+                                              params::StateType::Discrete(1)],
+                                              &BTreeSet::from([1]));
+        assert_eq!(0, idx);
+
+
+        let idx = net.get_param_index_from_custom_parent_set(&vec![
+                                              params::StateType::Discrete(0), 
+                                              params::StateType::Discrete(0), 
+                                              params::StateType::Discrete(1)],
+                                              &BTreeSet::from([1,2]));
+        assert_eq!(2, idx);
     }
 }

src/network.rs

@@ -20,13 +20,20 @@ pub trait Network {
 
     ///Get all the indices of the nodes contained inside the network
     fn get_node_indices(&self) -> std::ops::Range<usize>;
+    fn get_number_of_nodes(&self) -> usize;
     fn get_node(&self, node_idx: usize) -> &node::Node;
     fn get_node_mut(&mut self, node_idx: usize) -> &mut node::Node;
 
-    ///Compute the index that must be used to access the parameter of a node given a specific
+    ///Compute the index that must be used to access the parameters of a node given a specific
     ///configuration of the network. Usually, the only values really used in *current_state* are
     ///the ones in the parent set of the *node*.
     fn get_param_index_network(&self, node: usize, current_state: &Vec<params::StateType>) -> usize;
+
+
+    ///Compute the index that must be used to access the parameters of a node given a specific
+    ///configuration of the network and a generic parent_set. Usually, the only values really used
+    ///in *current_state* are the ones in the parent set of the *node*.
+    fn get_param_index_from_custom_parent_set(&self, current_state: &Vec<params::StateType>, parent_set: &BTreeSet<usize>) -> usize;
     fn get_parent_set(&self, node: usize) -> BTreeSet<usize>;
     fn get_children_set(&self, node: usize) -> BTreeSet<usize>;
 }

src/parameter_learning.rs

@@ -1,21 +1,197 @@
-use crate::params::*;
 use crate::network;
+use crate::params::*;
 use crate::tools;
 use ndarray::prelude::*;
+use ndarray::{concatenate, Slice};
 use std::collections::BTreeSet;
 
-pub fn MLE(net: Box<dyn network::Network>, 
-           dataset: &tools::Dataset, 
-           node: usize, 
-           parent_set: Option<BTreeSet<usize>>) {
-    
+pub fn MLE(
+    net: Box<&dyn network::Network>,
+    dataset: &tools::Dataset,
+    node: usize,
+    parent_set: Option<BTreeSet<usize>>,
+) -> (Array3<f64>, Array3<usize>, Array2<f64>) {
+    //TODO: make this function general. Now it works only on ContinousTimeDiscreteState nodes
+
+    //Use parent_set from parameter if present. Otherwise use parent_set from network.
     let parent_set = match parent_set {
         Some(p) => p,
-        None => net.get_parent_set(node)
+        None => net.get_parent_set(node),
     };
     
+    //Get the number of values assumable by the node
+    let node_domain = net
+        .get_node(node.clone())
+        .params
+        .get_reserved_space_as_parent();
 
-    
+    //Get the number of values assumable by each parent of the node
+    let parentset_domain: Vec<usize> = parent_set
+        .iter()
+        .map(|x| {
+            net.get_node(x.clone())
+                .params
+                .get_reserved_space_as_parent()
+        })
+        .collect();
+
+    //Vector used to convert a specific configuration of the parent_set to the corresponding index
+    //for CIM, M and T
+    let mut vector_to_idx: Array1<usize> = Array::zeros(net.get_number_of_nodes());
 
+    parent_set
+        .iter()
+        .zip(parentset_domain.iter())
+        .fold(1, |acc, (idx, x)| {
+            vector_to_idx[*idx] = acc;
+            acc * x
+        });
     
+    //Number of transition given a specific configuration of the parent set
+    let mut M: Array3<usize> =
+        Array::zeros((parentset_domain.iter().product(), node_domain, node_domain));
+
+    //Residence time given a specific configuration of the parent set
+    let mut T: Array2<f64> = Array::zeros((parentset_domain.iter().product(), node_domain));
+
+    //Compute the sufficient statistics
+    for trj in dataset.trajectories.iter() {
+        for idx in 0..(trj.time.len() - 1) {
+            let t1 = trj.time[idx];
+            let t2 = trj.time[idx + 1];
+            let ev1 = trj.events.row(idx);
+            let ev2 = trj.events.row(idx + 1);
+            let idx1 = vector_to_idx.dot(&ev1);
+
+            T[[idx1, ev1[node]]] += t2 - t1;
+            if ev1[node] != ev2[node] {
+                M[[idx1, ev1[node], ev2[node]]] += 1;
+            }
+        }
+    }
+
+    //Compute the CIM as M[i,x,y]/T[i,x]  
+    let mut CIM: Array3<f64> = Array::zeros((M.shape()[0], M.shape()[1], M.shape()[2]));
+    CIM.axis_iter_mut(Axis(2))
+        .zip(M.mapv(|x| x as f64).axis_iter(Axis(2)))
+        .for_each(|(mut C, m)| C.assign(&(&m/&T)));
+
+    //Set the diagonal of the inner matrices to the the row sum multiplied by -1
+    let tmp_diag_sum: Array2<f64> = CIM.sum_axis(Axis(2)).mapv(|x| x * -1.0);
+    CIM.outer_iter_mut()
+        .zip(tmp_diag_sum.outer_iter())
+        .for_each(|(mut C, diag)| {
+            C.diag_mut().assign(&diag);
+        });
+    return (CIM, M, T);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::ctbn::*;
+    use crate::network::Network;
+    use crate::node;
+    use crate::params;
+    use ndarray::arr3;
+    use std::collections::BTreeSet;
+    use tools::*;
+
+    fn define_binary_node(name: String) -> node::Node {
+        let mut domain = BTreeSet::new();
+        domain.insert(String::from("A"));
+        domain.insert(String::from("B"));
+        let param = params::DiscreteStatesContinousTimeParams::init(domain);
+        let n = node::Node::init(params::Params::DiscreteStatesContinousTime(param), name);
+        return n;
+    }
+
+
+    fn define_ternary_node(name: String) -> node::Node {
+        let mut domain = BTreeSet::new();
+        domain.insert(String::from("A"));
+        domain.insert(String::from("B"));
+        domain.insert(String::from("C"));
+        let param = params::DiscreteStatesContinousTimeParams::init(domain);
+        let n = node::Node::init(params::Params::DiscreteStatesContinousTime(param), name);
+        return n;
+    }
+
+    #[test]
+    fn learn_binary_cim_MLE() {
+        let mut net = CtbnNetwork::init();
+        let n1 = net
+            .add_node(define_binary_node(String::from("n1")))
+            .unwrap();
+        let n2 = net
+            .add_node(define_binary_node(String::from("n2")))
+            .unwrap();
+        net.add_edge(n1, n2);
+
+        match &mut net.get_node_mut(n1).params {
+            params::Params::DiscreteStatesContinousTime(param) => {
+                param.cim = Some(arr3(&[[[-3.0, 3.0], [2.0, -2.0]]]));
+            }
+        }
+
+        match &mut net.get_node_mut(n2).params {
+            params::Params::DiscreteStatesContinousTime(param) => {
+                param.cim = Some(arr3(&[
+                    [[-1.0, 1.0], [4.0, -4.0]],
+                    [[-6.0, 6.0], [2.0, -2.0]],
+                ]));
+            }
+        }
+
+        let data = trajectory_generator(Box::new(&net), 10, 100.0);
+
+        let (CIM, M, T) = MLE(Box::new(&net), &data, 1, None);
+        print!("CIM: {:?}\nM: {:?}\nT: {:?}\n", CIM, M, T);
+        assert_eq!(CIM.shape(), [2, 2, 2]);
+        assert_relative_eq!(-1.0, CIM[[0, 0, 0]], epsilon=0.2);
+        assert_relative_eq!(-4.0, CIM[[0, 1, 1]], epsilon=0.2);
+        assert_relative_eq!(-6.0, CIM[[1, 0, 0]], epsilon=0.2);
+        assert_relative_eq!(-2.0, CIM[[1, 1, 1]], epsilon=0.2);
+    }
+
+
+    #[test]
+    fn learn_ternary_cim_MLE() {
+        let mut net = CtbnNetwork::init();
+        let n1 = net
+            .add_node(define_ternary_node(String::from("n1")))
+            .unwrap();
+        let n2 = net
+            .add_node(define_ternary_node(String::from("n2")))
+            .unwrap();
+        net.add_edge(n1, n2);
+
+        match &mut net.get_node_mut(n1).params {
+            params::Params::DiscreteStatesContinousTime(param) => {
+                param.cim = Some(arr3(&[[[-3.0, 2.0, 1.0], 
+                                      [1.5, -2.0, 0.5],
+                                      [0.4, 0.6, -1.0]]]));
+            }
+        }
+
+        match &mut net.get_node_mut(n2).params {
+            params::Params::DiscreteStatesContinousTime(param) => {
+                param.cim = Some(arr3(&[
+                    [[-1.0, 0.5, 0.5], [3.0, -4.0, 1.0], [0.9, 0.1, -1.0]],
+                    [[-6.0, 2.0, 4.0], [1.5, -2.0, 0.5], [3.0, 1.0, -4.0]],
+                    [[-1.0, 0.1, 0.9], [2.0, -2.5, 0.5], [0.9, 0.1, -1.0]],
+                ]));
+            }
+        }
+
+        let data = trajectory_generator(Box::new(&net), 100, 200.0);
+
+        let (CIM, M, T) = MLE(Box::new(&net), &data, 1, None);
+        print!("CIM: {:?}\nM: {:?}\nT: {:?}\n", CIM, M, T);
+        assert_eq!(CIM.shape(), [3, 3, 3]);
+        assert_relative_eq!(-1.0, CIM[[0, 0, 0]], epsilon=0.2);
+        assert_relative_eq!(-4.0, CIM[[0, 1, 1]], epsilon=0.2);
+        assert_relative_eq!(-1.0, CIM[[0, 2, 2]], epsilon=0.2);
+        assert_relative_eq!(0.5, CIM[[0, 0, 1]], epsilon=0.2);
+    }
 }

src/params.rs

@@ -16,7 +16,7 @@ pub enum ParamsError {
 /// Allowed type of states
 #[derive(Clone)]
 pub enum StateType {
-    Discrete(u32),
+    Discrete(usize),
 }
 
 /// Parameters
@@ -91,7 +91,7 @@ impl ParamsTrait for DiscreteStatesContinousTimeParams {
 
     fn get_random_state_uniform(&self) -> StateType {
         let mut rng = rand::thread_rng();
-        StateType::Discrete(rng.gen_range(0..(self.domain.len() as u32)))
+        StateType::Discrete(rng.gen_range(0..(self.domain.len())))
     }
 
     fn get_random_residence_time(&self, state: usize, u: usize) -> Result<f64, ParamsError> {
@@ -138,7 +138,7 @@ impl ParamsTrait for DiscreteStatesContinousTimeParams {
                     next_state.0 + 1
                 };
 
-                Ok(StateType::Discrete(next_state as u32))
+                Ok(StateType::Discrete(next_state))
             }
             Option::None => Err(ParamsError::ParametersNotInitialized(String::from(
                 "CIM not initialized",
@@ -177,7 +177,7 @@ mod tests {
     #[test]
     fn test_uniform_generation() {
         let param = create_ternary_discrete_time_continous_param();
-        let mut states = Array1::<u32>::zeros(10000);
+        let mut states = Array1::<usize>::zeros(10000);
 
         states.mapv_inplace(|_| {
             if let StateType::Discrete(val) = param.get_random_state_uniform() {
@@ -194,7 +194,7 @@ mod tests {
     #[test]
     fn test_random_generation_state() {
         let param = create_ternary_discrete_time_continous_param();
-        let mut states = Array1::<u32>::zeros(10000);
+        let mut states = Array1::<usize>::zeros(10000);
 
         states.mapv_inplace(|_| {
             if let StateType::Discrete(val) = param.get_random_state(1, 0).unwrap() {

src/tools.rs

@@ -5,16 +5,16 @@ use crate::params;
 use crate::params::ParamsTrait;
 
 pub struct Trajectory {
-    time: Array1<f64>,
-    events: Array2<u32>
+    pub time: Array1<f64>,
+    pub events: Array2<usize>
 }
 
 pub struct Dataset {
-    trajectories: Vec<Trajectory>
+    pub trajectories: Vec<Trajectory>
 }
 
 
-pub fn trajectory_generator(net: Box<dyn network::Network>, n_trajectories: u64, t_end: f64) -> Dataset {
+pub fn trajectory_generator(net: Box<&dyn network::Network>, n_trajectories: u64, t_end: f64) -> Dataset {
     let mut dataset = Dataset{
         trajectories: Vec::new()
     };
@@ -23,7 +23,7 @@ pub fn trajectory_generator(net: Box<dyn network::Network>, n_trajectories: u64,
     for _ in 0..n_trajectories {
         let mut t = 0.0;
         let mut time: Vec<f64> = Vec::new();
-        let mut events: Vec<Array1<u32>> = Vec::new();
+        let mut events: Vec<Array1<usize>> = Vec::new();
         let mut current_state: Vec<params::StateType> = node_idx.iter().map(|x| {
             net.get_node(*x).params.get_random_state_uniform()
         }).collect();
@@ -135,7 +135,7 @@ mod tests {
             }
         }
 
-        let data = trajectory_generator(Box::from(net), 4, 1.0);
+        let data = trajectory_generator(Box::new(&net), 4, 1.0);
 
         assert_eq!(4, data.trajectories.len());
         assert_relative_eq!(1.0, data.trajectories[0].time[data.trajectories[0].time.len()-1]);