From cd5611079caae782f148397a0ebad465aea6faef Mon Sep 17 00:00:00 2001
From: gaxler <g.axler@gmail.com>
Date: Sat, 30 Jan 2021 19:29:33 -0800
Subject: [PATCH] Fit OneHotEncoder

---
 src/preprocessing/categorical_encoders.rs | 56 ++++++++++++++++++-----
 1 file changed, 45 insertions(+), 11 deletions(-)

diff --git a/src/preprocessing/categorical_encoders.rs b/src/preprocessing/categorical_encoders.rs
index 31d3500..794c1d6 100644
--- a/src/preprocessing/categorical_encoders.rs
+++ b/src/preprocessing/categorical_encoders.rs
@@ -75,32 +75,66 @@ fn find_new_idxs(num_params: usize, cat_sizes: &[usize], encoded_idxs: &[usize])
         .collect();
     new_param_idxs
 }
+fn validate_col_is_categorical<T:  Categorizable>(data: &Vec<T>) -> bool {
+    for v in data {
+        if !v.is_valid() { return false}
+    }
+    true
+}
 /// Encode Categorical variavbles of data matrix to one-hot
 pub struct OneHotEncoder {
-    series_encoders: Vec<SeriesOneHotEncoder<HashableReal>>,
-    categorical_param_idxs: Vec<usize>,
+    series_encoders: Vec<SeriesOneHotEncoder<CategoricalFloat>>,
+    col_idx_categorical: Vec<usize>,
 }
 
-impl<T: RealNumber, M: Matrix<T>> OneHotEncoder {
+impl OneHotEncoder {
     /// PlaceHolder
 
-    pub fn fit(data: &M, params: OneHotEncoderParams) -> Result<OneHotEncoder, Failed> {
-        match (params.categorical_param_idxs, params.infer_categorical) {
+    pub fn fit<T:  Categorizable, M: Matrix<T>>(
+        data: &M,
+        params: OneHotEncoderParams,
+    ) -> Result<OneHotEncoder, Failed> {
+        match (params.col_idx_categorical, params.infer_categorical) {
             (None, false) => Err(Failed::fit(
                 "Must pass categorical series ids or infer flag",
             )),
 
-            (Some(idxs), true) => Err(Failed::fit(
+            (Some(_idxs), true) => Err(Failed::fit(
                 "Ambigous parameters, got both infer and categroy ids",
             )),
 
-            (Some(idxs), false) => Ok(Self {
-                series_encoders: Self::build_series_encoders::<T, M>(data, &idxs[..]),
-                categorical_param_idxs: idxs,
-            }),
+            (Some(mut idxs), false) => {
+                // make sure categories have same order as data columns
+                idxs.sort();
+
+                let (nrows, _) = data.shape();
+
+                // col buffer to avoid allocations
+                let mut col_buf: Vec<T> = iter::repeat(T::zero()).take(nrows).collect();
+        
+                let mut res: Vec<SeriesOneHotEncoder<CategoricalFloat>> = Vec::with_capacity(idxs.len());
+                
+                for &idx in &idxs {
+                    data.copy_col_as_vec(idx, &mut col_buf);
+                    if !validate_col_is_categorical(&col_buf) {
+                        let msg = format!("Column {} of data matrix containts non categorizable (integer) values", idx);
+                        return Err(Failed::fit(&msg[..]))
+                    }
+                    let hashable_col = col_buf.iter().map(|v| v.to_category());
+                    res.push(SeriesOneHotEncoder::fit_to_iter(hashable_col));
+                }
+
+                Ok(Self {
+                    series_encoders: res, //Self::build_series_encoders::<T, M>(data, &idxs[..]),
+                    col_idx_categorical: idxs,
+                })
+            }
 
             (None, true) => {
-                todo!("implement categorical auto-inference")
+                todo!("Auto-Inference for Categorical Variables not yet implemented")
+            }
+        }
+    }
             }
         }
     }