From 04229f8bf64738536e3576290c32783c57b567fe Mon Sep 17 00:00:00 2001
From: wassname <wassname@users.noreply.github.com>
Date: Sun, 8 Nov 2020 10:53:49 +0800
Subject: [PATCH] randomize indexing

---
 seq2seq_time/data/dataset.py | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/seq2seq_time/data/dataset.py b/seq2seq_time/data/dataset.py
index 7f2ff7c..d344917 100644
--- a/seq2seq_time/data/dataset.py
+++ b/seq2seq_time/data/dataset.py
@@ -32,7 +32,8 @@ class Seq2SeqDataSet(torch.utils.data.Dataset):
         assert_no_objects(df)
 
         self.freq = df.index.freq.freqstr
-        self.df = df.dropna(subset=columns_target).ffill()
+        self.df = df.dropna(subset = columns_target).ffill()
+        
 
         self.window_past = window_past
         self.window_future = window_future
@@ -43,6 +44,10 @@ class Seq2SeqDataSet(torch.utils.data.Dataset):
         self._icol_blank = [df.drop(columns = columns_target).columns.tolist().index(n) for n in columns_past]
         self._x = self.df.drop(columns = self.columns_target).values
         self._y = self.df[columns_target].values
+        
+        # Sometimes we want to have it shuffled, but the same each time
+        np.random.seed(42)
+        self._rand_index = np.random.permutation(len(self))
 
     def get_components(self, i):
         """Get past and future rows."""
@@ -71,23 +76,25 @@ class Seq2SeqDataSet(torch.utils.data.Dataset):
         return x_past, y_past, x_future, y_future
 
 
-    def __getitem__(self, i):
+    def __getitem__(self, j):
         """This is how python implements square brackets"""
-        if i<0:
+        if j<0:
             # Handle negative integers
-            i = len(self)+i
+            j = len(self)+j
+        i = self._rand_index[j]
         data = self.get_components(i)
         # From dataframe to torch
         return [d.astype(np.float32) for d in data]
     
     
-    def get_rows(self, i):
+    def get_rows(self, j):
         """
         Output pandas dataframes for display purposes.
         """
-        if i<0:
+        if j<0:
             # Handle negative integers
-            i = len(self)+i
+            j = len(self) + j
+        i = self._rand_index[j]
         x_cols = list(self.df.drop(columns=self.columns_target).columns) + ['tsp_days', 'is_past']
         x_past, y_past, x_future, y_future = self.get_components(i)
         t_past = self.df.index[i:i+self.window_past]