✨ Working NeuraGraph construction

Cargo.toml

@@ -19,6 +19,7 @@ rand_distr = "0.4.3"
 textplots = "0.8.0"
 image = { version = "0.24.6", optional = true }
 viuer = { version = "0.6.2", optional = true }
+dyn-clone = "1.0.11"
 
 [dev-dependencies]
 image = "0.24.6"

src/err.rs

@@ -92,8 +92,10 @@ pub struct NeuraDimensionsMismatch {
     pub new: NeuraShape,
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum NeuraGraphErr {
     MissingNode(String),
     InvalidName(String),
+    LayerErr(String),
+    Cyclic,
 }

src/network/graph/mod.rs

@@ -1,3 +1,5 @@
+#![allow(dead_code)] // TODO: remove this
+
 use std::collections::{HashMap, HashSet, VecDeque};
 
 use crate::prelude::*;
@@ -7,22 +9,28 @@ mod node;
 pub use node::*;
 
 pub struct NeuraGraphPartial<Data> {
-    pub nodes: Vec<Box<dyn NeuraGraphNodeTrait<Data>>>,
+    pub nodes: Vec<Box<dyn NeuraGraphNodePartial<Data>>>,
     pub output: String,
     pub input: String,
 }
 
+#[derive(Clone, Debug, Copy, PartialEq, Eq, Hash)]
+enum GraphIndex {
+    Input,
+    Node(usize),
+}
+
 impl<Data> NeuraGraphPartial<Data> {
-    fn get_index_map(&self) -> Result<HashMap<String, usize>, NeuraGraphErr> {
+    fn get_index_map(&self) -> Result<HashMap<String, GraphIndex>, NeuraGraphErr> {
         let mut result = HashMap::with_capacity(self.nodes.len());
 
-        result.insert(self.input.clone(), 0);
+        result.insert(self.input.clone(), GraphIndex::Input);
 
         for (index, node) in self.nodes.iter().enumerate() {
             if result.contains_key(node.name()) {
                 return Err(NeuraGraphErr::InvalidName(node.name().to_string()));
             }
-            result.insert(node.name().to_string(), index + 1);
+            result.insert(node.name().to_string(), GraphIndex::Node(index));
         }
 
         Ok(result)
@@ -30,9 +38,15 @@ impl<Data> NeuraGraphPartial<Data> {
 
     fn get_reverse_graph(
         &self,
-        index_map: &HashMap<String, usize>,
-    ) -> Result<Vec<HashSet<usize>>, NeuraGraphErr> {
-        let mut result = vec![HashSet::new(); self.nodes.len()];
+        index_map: &HashMap<String, GraphIndex>,
+    ) -> Result<HashMap<GraphIndex, HashSet<GraphIndex>>, NeuraGraphErr> {
+        let mut result = HashMap::new();
+
+        result.insert(GraphIndex::Input, HashSet::new());
+
+        for i in 0..self.nodes.len() {
+            result.insert(GraphIndex::Node(i), HashSet::new());
+        }
 
         for (index, node) in self.nodes.iter().enumerate() {
             for input in node.inputs() {
@@ -40,7 +54,10 @@ impl<Data> NeuraGraphPartial<Data> {
                     .get(input)
                     .copied()
                     .ok_or_else(|| NeuraGraphErr::MissingNode(input.clone()))?;
-                result[input_index].insert(index + 1);
+                result
+                    .get_mut(&input_index)
+                    .expect("index_map returned invalid values")
+                    .insert(GraphIndex::Node(index));
             }
         }
 
@@ -49,13 +66,13 @@ impl<Data> NeuraGraphPartial<Data> {
 
     fn get_node_order(
         &self,
-        index_map: &HashMap<String, usize>,
-        reverse_graph: &Vec<HashSet<usize>>,
+        index_map: &HashMap<String, GraphIndex>,
+        reverse_graph: &HashMap<GraphIndex, HashSet<GraphIndex>>,
     ) -> Result<Vec<usize>, NeuraGraphErr> {
         let mut result: Vec<usize> = Vec::new();
-        let mut closed: HashSet<usize> = HashSet::with_capacity(self.nodes.len());
+        let mut closed: HashSet<GraphIndex> = HashSet::with_capacity(self.nodes.len());
         let mut open = VecDeque::with_capacity(self.nodes.len());
-        open.push_front(0usize);
+        open.push_front(GraphIndex::Input);
 
         /*
         index_map.get(&self.output)
@@ -69,49 +86,68 @@ impl<Data> NeuraGraphPartial<Data> {
             }
 
             closed.insert(current);
-            result.push(current);
+            // Do not put 0 (the input) in result
+            if let GraphIndex::Node(index) = current {
+                result.push(index);
+            }
 
-            for output_index in reverse_graph[current].iter().copied() {
-                assert!(output_index > 0);
+            println!("{:?}", current);
 
+            for next_node in reverse_graph[&current].iter().copied() {
                 // Ignore nodes that are already in the closed set
-                if closed.contains(&output_index) {
+                if closed.contains(&next_node) {
                     continue;
                 }
 
-                let inputs = self.nodes[output_index - 1].inputs();
+                let GraphIndex::Node(node_index) = next_node else {
+                    panic!("Unreachable: cannot have GraphIndex::Input as the output of a node");
+                };
+
+                let inputs = self.nodes[node_index].inputs();
 
-                // Only consider nodes whose inputs are in the closed set
+                // Only consider nodes whose inputs are in the closed set (meaning they would be ready to be evaluated)
                 if !inputs
                     .iter()
                     .all(|input| closed.contains(&index_map[input]))
                 {
                     continue;
                 }
+
+                open.push_front(next_node);
+            }
         }
+
+        if result.len() != self.nodes.len() {
+            // TODO: verify that if result.len() != self.nodes.len(), then there is a cyclic subgraph
+
+            return Err(NeuraGraphErr::Cyclic);
         }
 
         Ok(result)
     }
 }
 
+#[derive(Debug)]
 struct NeuraGraphNodeConstructed<Data> {
-    node: Box<dyn NeuraGraphNodeTrait<Data>>,
+    node: Box<dyn NeuraGraphNodeEval<Data>>,
     inputs: Vec<usize>,
     output: usize,
 }
 
+#[derive(Debug)]
 pub struct NeuraGraph<Data> {
     /// ## Class invariants
     ///
     /// - The order of nodes should match with the order of execution, ie.
     ///   `forall (x, y), nodes = [..., x, ..., y, ...] => !(y in x.node.inputs)`
     /// - `nodes[0].inputs = [0]`
-    /// - `nodes[nodes.len() - 1].output = buffer.len() - 1`
     nodes: Vec<NeuraGraphNodeConstructed<Data>>,
 
     input_shape: NeuraShape,
     output_shape: NeuraShape,
+
+    output_index: usize,
+    buffer_size: usize,
 }
 
 impl<Data> NeuraShapedLayer for NeuraGraph<Data> {
@@ -126,6 +162,188 @@ impl<Data> NeuraPartialLayer for NeuraGraphPartial<Data> {
     type Err = NeuraGraphErr;
 
     fn construct(self, input_shape: NeuraShape) -> Result<Self::Constructed, Self::Err> {
-        todo!()
+        let index_map = self.get_index_map()?;
+        let reverse_graph = self.get_reverse_graph(&index_map)?;
+
+        // List out the nodes in their execution order
+        let node_order = self.get_node_order(&index_map, &reverse_graph)?;
+        let mut new_index_map: HashMap<String, usize> = HashMap::from_iter(
+            node_order
+                .iter()
+                .map(|&i| (self.nodes[i].name().to_string(), i)),
+        );
+        new_index_map.insert(self.input.clone(), 0);
+
+        // TODO: filter out the nodes that are not necessary for computing the result (BFS from the output node back to the inputs)
+        // A temporary solution can be to trim the graph
+        let output_index = new_index_map
+            .get(&self.output)
+            .copied()
+            .ok_or_else(|| NeuraGraphErr::MissingNode(self.output.clone()))?;
+
+        let mut nodes = Vec::with_capacity(self.nodes.len());
+        let mut shapes: Vec<Option<NeuraShape>> = vec![None; self.nodes.len() + 1];
+        shapes[0] = Some(input_shape);
+
+        for index in node_order.into_iter() {
+            let node = &*self.nodes[index];
+            let node_inputs = node.inputs();
+            let mut inputs = Vec::with_capacity(node_inputs.len());
+            let mut input_shapes = Vec::with_capacity(node_inputs.len());
+
+            for input in node_inputs {
+                let input_index = new_index_map.get(input).copied().expect(
+                    "Unreachable: new_index_map should contain all nodes defined and all nodes should have existing nodes as input"
+                );
+                inputs.push(input_index);
+                input_shapes.push(shapes[input_index].expect(
+                    "Unreachable: the order of execution should guarantee that all inputs have appeared before")
+                );
+            }
+
+            let (constructed, output_shape) = node
+                .construct(input_shapes)
+                .map_err(|e| NeuraGraphErr::LayerErr(e))?;
+
+            shapes[index] = Some(output_shape);
+
+            nodes.push(NeuraGraphNodeConstructed {
+                node: constructed,
+                inputs,
+                output: new_index_map
+                    .get(node.name())
+                    .copied()
+                    .unwrap_or_else(|| unreachable!()),
+            });
+        }
+
+        let output_shape = shapes[output_index].unwrap_or_else(|| unreachable!());
+
+        Ok(NeuraGraph {
+            nodes,
+            input_shape,
+            output_shape,
+            output_index,
+            buffer_size: self.nodes.len() + 1,
+        })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::network::residual::NeuraAxisAppend;
+
+    use super::*;
+
+    #[test]
+    fn test_construct_simple_graph() {
+        let graph = NeuraGraphPartial {
+            nodes: vec![NeuraGraphNode::new(
+                vec!["input".to_string()],
+                NeuraAxisAppend,
+                neura_layer!("dense", 10),
+                "output".to_string(),
+            )
+            .as_boxed()],
+            output: "output".to_string(),
+            input: "input".to_string(),
+        };
+
+        let constructed = graph.construct(NeuraShape::Vector(5));
+
+        assert!(constructed.is_ok());
+    }
+
+    #[test]
+    fn test_construct_deep_graph() {
+        let graph = NeuraGraphPartial {
+            nodes: vec![
+                // Node intentionally out of order
+                NeuraGraphNode::new(
+                    vec!["inter".to_string(), "inter2".to_string()],
+                    NeuraAxisAppend,
+                    neura_layer!("dense", 2),
+                    "output".to_string(),
+                )
+                .as_boxed(),
+                NeuraGraphNode::new(
+                    vec!["input".to_string()],
+                    NeuraAxisAppend,
+                    neura_layer!("dense", 10),
+                    "inter".to_string(),
+                )
+                .as_boxed(),
+                NeuraGraphNode::new(
+                    vec!["inter".to_string()],
+                    NeuraAxisAppend,
+                    neura_layer!("dense", 20),
+                    "inter2".to_string(),
+                )
+                .as_boxed(),
+            ],
+            output: "output".to_string(),
+            input: "input".to_string(),
+        };
+
+        let index_map = graph.get_index_map().unwrap();
+        let reverse_graph = graph.get_reverse_graph(&index_map).unwrap();
+        assert_eq!(
+            graph.get_node_order(&index_map, &reverse_graph),
+            Ok(vec![1, 2, 0])
+        );
+
+        let constructed = graph.construct(NeuraShape::Vector(5));
+
+        assert!(constructed.is_ok());
+    }
+
+    #[test]
+    fn test_construct_cyclic_graph() {
+        let graph = NeuraGraphPartial {
+            nodes: vec![NeuraGraphNode::new(
+                vec!["input".to_string(), "output".to_string()],
+                NeuraAxisAppend,
+                neura_layer!("dense", 10),
+                "output".to_string(),
+            )
+            .as_boxed()],
+            output: "output".to_string(),
+            input: "input".to_string(),
+        };
+
+        let constructed = graph.construct(NeuraShape::Vector(5));
+
+        assert_eq!(constructed.unwrap_err(), NeuraGraphErr::Cyclic);
+    }
+
+    #[test]
+    fn test_construct_disjoint_graph() {
+        let graph = NeuraGraphPartial {
+            nodes: vec![
+                NeuraGraphNode::new(
+                    vec!["input".to_string()],
+                    NeuraAxisAppend,
+                    neura_layer!("dense", 10),
+                    "inter".to_string(),
+                )
+                .as_boxed(),
+                NeuraGraphNode::new(
+                    vec!["missing".to_string()],
+                    NeuraAxisAppend,
+                    neura_layer!("dense", 10),
+                    "output".to_string(),
+                )
+                .as_boxed(),
+            ],
+            output: "output".to_string(),
+            input: "input".to_string(),
+        };
+
+        let constructed = graph.construct(NeuraShape::Vector(5));
+
+        assert_eq!(
+            constructed.unwrap_err(),
+            NeuraGraphErr::MissingNode(String::from("missing"))
+        );
     }
 }

src/network/graph/node.rs

@@ -1,12 +1,28 @@
-use crate::{layer::NeuraLayer, network::residual::NeuraSplitInputs};
+use dyn_clone::DynClone;
 
-pub trait NeuraGraphNodeTrait<Data> {
-    fn eval<'a>(&'a self, inputs: &[Data]) -> Data;
+use crate::{
+    err::NeuraAxisErr,
+    layer::{NeuraLayer, NeuraShapedLayer},
+    network::residual::{NeuraCombineInputs, NeuraSplitInputs},
+    prelude::{NeuraPartialLayer, NeuraShape},
+};
 
+// TODO: split into two  traits
+pub trait NeuraGraphNodePartial<Data>: DynClone + std::fmt::Debug {
     fn inputs<'a>(&'a self) -> &'a [String];
     fn name<'a>(&'a self) -> &'a str;
+
+    fn construct(
+        &self,
+        input_shapes: Vec<NeuraShape>,
+    ) -> Result<(Box<dyn NeuraGraphNodeEval<Data>>, NeuraShape), String>;
 }
 
+pub trait NeuraGraphNodeEval<Data>: DynClone + std::fmt::Debug {
+    fn eval<'a>(&'a self, inputs: &[Data]) -> Data;
+}
+
+#[derive(Clone, Debug)]
 pub struct NeuraGraphNode<Axis, Layer> {
     inputs: Vec<String>,
     axis: Axis,
@@ -25,10 +41,20 @@ impl<Axis, Layer> NeuraGraphNode<Axis, Layer> {
         }
     }
 
-    pub fn as_boxed<Data: Clone>(self) -> Box<dyn NeuraGraphNodeTrait<Data>>
+    pub fn as_boxed<Data: Clone>(self) -> Box<dyn NeuraGraphNodePartial<Data>>
     where
-        Axis: NeuraSplitInputs<Data> + 'static,
-        Layer: NeuraLayer<Axis::Combined, Output = Data> + 'static,
+        Axis: NeuraSplitInputs<Data>
+            + NeuraCombineInputs<NeuraShape, Combined = Result<NeuraShape, NeuraAxisErr>>
+            + Clone
+            + std::fmt::Debug
+            + 'static,
+        Layer: NeuraPartialLayer + Clone + std::fmt::Debug + 'static,
+        Layer::Constructed: NeuraShapedLayer
+            + NeuraLayer<<Axis as NeuraCombineInputs<Data>>::Combined, Output = Data>
+            + Clone
+            + std::fmt::Debug
+            + 'static,
+        Layer::Err: std::fmt::Debug,
     {
         Box::new(self)
     }
@@ -36,16 +62,36 @@ impl<Axis, Layer> NeuraGraphNode<Axis, Layer> {
 
 impl<
         Data: Clone,
-        Axis: NeuraSplitInputs<Data>,
-        Layer: NeuraLayer<Axis::Combined, Output = Data>,
-    > NeuraGraphNodeTrait<Data> for NeuraGraphNode<Axis, Layer>
+        Axis: NeuraSplitInputs<Data> + Clone + std::fmt::Debug,
+        Layer: NeuraLayer<<Axis as NeuraCombineInputs<Data>>::Combined, Output = Data>
+            + Clone
+            + std::fmt::Debug,
+    > NeuraGraphNodeEval<Data> for NeuraGraphNode<Axis, Layer>
 {
     fn eval<'a>(&'a self, inputs: &[Data]) -> Data {
         // TODO: use to_vec_in?
         let combined = self.axis.combine(inputs.to_vec());
         self.layer.eval(&combined)
     }
+}
 
+impl<
+        Data: Clone,
+        Axis: NeuraSplitInputs<Data>
+            + NeuraCombineInputs<NeuraShape, Combined = Result<NeuraShape, NeuraAxisErr>>
+            + Clone
+            + std::fmt::Debug
+            + 'static,
+        Layer: NeuraPartialLayer + Clone + std::fmt::Debug,
+    > NeuraGraphNodePartial<Data> for NeuraGraphNode<Axis, Layer>
+where
+    Layer::Constructed: NeuraShapedLayer
+        + NeuraLayer<<Axis as NeuraCombineInputs<Data>>::Combined, Output = Data>
+        + Clone
+        + std::fmt::Debug
+        + 'static,
+    Layer::Err: std::fmt::Debug,
+{
     fn inputs<'a>(&'a self) -> &'a [String] {
         &self.inputs
     }
@@ -53,4 +99,31 @@ impl<
     fn name<'a>(&'a self) -> &'a str {
         &self.name
     }
+
+    fn construct(
+        &self,
+        input_shapes: Vec<NeuraShape>,
+    ) -> Result<(Box<dyn NeuraGraphNodeEval<Data>>, NeuraShape), String> {
+        let combined = self
+            .axis
+            .combine(input_shapes)
+            .map_err(|err| format!("{:?}", err))?;
+
+        let constructed_layer = self
+            .layer
+            .clone()
+            .construct(combined)
+            .map_err(|err| format!("{:?}", err))?;
+        let output_shape = constructed_layer.output_shape();
+
+        Ok((
+            Box::new(NeuraGraphNode {
+                inputs: self.inputs.clone(),
+                axis: self.axis.clone(),
+                layer: constructed_layer,
+                name: self.name.clone(),
+            }),
+            output_shape,
+        ))
+    }
 }