Merge pull request #32 from maciejkula/fix/serialization

Fix EncodableRng JSON serialization.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rustlearn"
-version = "0.4.1"
+version = "0.4.2"
 description = "A machine learning package for Rust."
 documentation = "https://maciejkula.github.io/rustlearn/doc/rustlearn/"
 homepage = "https://github.com/maciejkula/rustlearn"
@@ -19,14 +19,14 @@ build = "build.rs"
 
 [dependencies]
 rand = "0.3"
-rustc-serialize = "0.3"
+rustc-serialize = "0.3.16"
 crossbeam = "0.2.9"
 
 [build-dependencies]
 gcc = "0.3"
 
 [dev-dependencies]
-bincode = "0.4.1"
+bincode = "0.6.0"
 csv = "0.14"
 hyper = "0.7.0"
 time = "0.1"

changelog.md

@@ -1,6 +1,10 @@
 # Changelog
 
-## [0.4.1][unreleased]
+## [0.4.2][unreleased]
+### Fixed
+- fixed EncodableRng dummy serialization implementation
+
+## [0.4.1][2016-08-26]
 ### Fixed
 - panic when removing constant features when splitting
   a decision tree

src/trees/decision_tree.rs

@@ -883,6 +883,8 @@ mod tests {
 
     use rand::{StdRng, SeedableRng};
 
+    use rustc_serialize::json;
+
     use bincode;
 
     #[cfg(feature = "all_tests")]
@@ -1174,6 +1176,7 @@ mod tests {
 
             model.fit(&x_train, &y_train).unwrap();
 
+            // Binary encoding
             let encoded = bincode::rustc_serialize::encode(&model, bincode::SizeLimit::Infinite)
                 .unwrap();
             let decoded: OneVsRestWrapper<DecisionTree> =
@@ -1182,6 +1185,15 @@ mod tests {
             let test_prediction = decoded.predict(&x_test).unwrap();
 
             test_accuracy += accuracy_score(&target.get_rows(&test_idx), &test_prediction);
+
+            // JSON encoding
+            let encoded = json::encode(&model).unwrap();
+            let decoded: OneVsRestWrapper<DecisionTree> =
+                json::decode(&encoded).unwrap();
+
+            let test_prediction = decoded.predict(&x_test).unwrap();
+
+            test_accuracy += accuracy_score(&target.get_rows(&test_idx), &test_prediction);
         }
 
         test_accuracy /= no_splits as f32;

src/utils/mod.rs

@@ -12,6 +12,7 @@ use prelude::*;
 /// Wrapper for making random number generators serializable.
 /// Does no actual encoding, and merely creates a new
 /// generator on decoding.
+/// This is because rand generators do not expose internal state.
 #[derive(Clone)]
 pub struct EncodableRng {
     pub rng: StdRng,
@@ -33,14 +34,16 @@ impl Default for EncodableRng {
 
 
 impl Encodable for EncodableRng {
-    fn encode<S: Encoder>(&self, _: &mut S) -> Result<(), S::Error> {
+    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
+        try!(s.emit_struct("EncodableRng", 0, |_| { Ok(()) }));
         Ok(())
     }
 }
 
 
 impl Decodable for EncodableRng {
-    fn decode<D: Decoder>(_: &mut D) -> Result<Self, D::Error> {
+    fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error> {
+        try!(d.read_struct("", 0, |_| { Ok(()) }));
         Ok((EncodableRng::new()))
     }
 }
@@ -81,3 +84,19 @@ pub fn check_matched_dimensions<T: IndexableMatrix>(X: &T, y: &Array) -> Result<
         Err("Data matrix and target array do not have the same number of rows")
     }
 }
+
+
+#[cfg(test)]
+mod tests {
+    use super::EncodableRng;
+
+    use rustc_serialize::json;
+
+    #[test]
+    fn test_encodable_rng_serialization() {
+        let rng = EncodableRng::new();
+
+        let serialized = json::encode(&rng).unwrap();
+        let _: EncodableRng = json::decode(&serialized).unwrap();
+    }
+}