diff --git a/src/data.py b/src/data.py
index 4230fd2..112ef89 100644
--- a/src/data.py
+++ b/src/data.py
@@ -8,6 +8,7 @@
 import random
 import json
 import numpy as np
+import torch.nn.functional as F
 
 class Dataset(torch.utils.data.Dataset):
     def __init__(self,
@@ -70,28 +71,45 @@ def sort_data(self):
     def get_example(self, index):
         return self.data[index]
 
-def encode_passages(batch_text_passages, tokenizer, max_length):
+def get_padded_tensor(ten_list, value = 0):
+    max_len = max([x.shape[1] for x in ten_list])
+    padded_list = []
+    for tensor in ten_list:
+        if(tensor.shape[1] < max_len):
+            tensor = F.pad(input=tensor, pad=(0, max_len - tensor.shape[1], 0, 0), mode='constant', value=value)
+        padded_list.append(tensor)
+    return padded_list
+    
+def encode_passages(batch_text_passages, tokenizer, max_length, pad_to_max_length):
+    # if padding to the max length, no padding to max passage length, and vice versa.
+    padding = not pad_to_max_length
+    
     passage_ids, passage_masks = [], []
     for k, text_passages in enumerate(batch_text_passages):
         p = tokenizer.batch_encode_plus(
             text_passages,
             max_length=max_length,
-            pad_to_max_length=True,
+            pad_to_max_length=pad_to_max_length,
+            padding=padding,
             return_tensors='pt',
             truncation=True
         )
-        passage_ids.append(p['input_ids'][None])
-        passage_masks.append(p['attention_mask'][None])
+        passage_ids.append(p['input_ids'])
+        passage_masks.append(p['attention_mask'])
+
+    passage_ids = get_padded_tensor(passage_ids, value=0)
+    passage_masks = get_padded_tensor(passage_masks, value=0)
 
-    passage_ids = torch.cat(passage_ids, dim=0)
-    passage_masks = torch.cat(passage_masks, dim=0)
+    passage_ids = torch.stack(passage_ids)
+    passage_masks = torch.stack(passage_masks)
     return passage_ids, passage_masks.bool()
 
 class Collator(object):
-    def __init__(self, text_maxlength, tokenizer, answer_maxlength=20):
+    def __init__(self, text_maxlength, tokenizer, answer_maxlength=20, pad_to_max_length=False):
         self.tokenizer = tokenizer
         self.text_maxlength = text_maxlength
         self.answer_maxlength = answer_maxlength
+        self.pad_to_max_length = pad_to_max_length
 
     def __call__(self, batch):
         assert(batch[0]['target'] != None)
@@ -115,7 +133,8 @@ def append_question(example):
         text_passages = [append_question(example) for example in batch]
         passage_ids, passage_masks = encode_passages(text_passages,
                                                      self.tokenizer,
-                                                     self.text_maxlength)
+                                                     self.text_maxlength,
+                                                     self.pad_to_max_length)
 
         return (index, target_ids, target_mask, passage_ids, passage_masks)
 
diff --git a/src/options.py b/src/options.py
index ce03207..3757071 100644
--- a/src/options.py
+++ b/src/options.py
@@ -89,6 +89,7 @@ def initialize_parser(self):
                         help='save model every <save_freq> steps during training')
         self.parser.add_argument('--eval_print_freq', type=int, default=1000,
                         help='print intermdiate results of evaluation every <eval_print_freq> steps')
+        self.parser.add_argument('--pad_to_max_length', action='store_true', help='Should the passages all be padded to the max length provided (True value here), or to the max length of the longest passage? (False value here).')
 
 
     def print_options(self, opt):
diff --git a/test_reader.py b/test_reader.py
index e53434e..25f8cbc 100644
--- a/test_reader.py
+++ b/test_reader.py
@@ -35,7 +35,7 @@ def evaluate(model, dataset, dataloader, tokenizer, opt):
     with torch.no_grad():
         for i, batch in enumerate(dataloader):
             (idx, _, _, context_ids, context_mask) = batch
-
+            
             if opt.write_crossattention_scores:
                 model.reset_score_storage()
 
@@ -101,7 +101,7 @@ def evaluate(model, dataset, dataloader, tokenizer, opt):
 
     tokenizer = transformers.T5Tokenizer.from_pretrained('t5-base', return_dict=False)
 
-    collator_function = src.data.Collator(opt.text_maxlength, tokenizer)
+    collator_function = src.data.Collator(opt.text_maxlength, tokenizer, pad_to_max_length=opt.pad_to_max_length)
     eval_examples = src.data.load_data(
         opt.eval_data, 
         global_rank=opt.global_rank, #use the global rank and world size attibutes to split the eval set on multiple gpus
diff --git a/train_reader.py b/train_reader.py
index f760992..3f288e6 100644
--- a/train_reader.py
+++ b/train_reader.py
@@ -154,7 +154,7 @@ def evaluate(model, dataset, tokenizer, collator, opt):
 
     #load data
     tokenizer = transformers.T5Tokenizer.from_pretrained(model_name)
-    collator = src.data.Collator(opt.text_maxlength, tokenizer, answer_maxlength=opt.answer_maxlength)
+    collator = src.data.Collator(opt.text_maxlength, tokenizer, answer_maxlength=opt.answer_maxlength, pad_to_max_length=opt.pad_to_max_length)
 
     # use golbal rank and world size to split the eval set on multiple gpus
     train_examples = src.data.load_data(