diff --git a/doc/source/_static/sidebar.js b/doc/source/_static/sidebar.js
index 5ffeb127a12ac6c5af6dd8a8e055c8c2e2932a96..19650a36c436392040ba4af8ce37ebd638d315f6 100644
--- a/doc/source/_static/sidebar.js
+++ b/doc/source/_static/sidebar.js
@@ -97,9 +97,9 @@ $(function() {
     // find the height of the viewport to center the '<<' in the page
     var viewport_height;
     if (window.innerHeight)
- 	  viewport_height = window.innerHeight;
+      viewport_height = window.innerHeight;
     else
-	  viewport_height = $(window).height();
+      viewport_height = $(window).height();
     var sidebar_offset = sidebar.offset().top;
     var sidebar_height = Math.max(bodywrapper.height(), sidebar.height());
     sidebarbutton.find('span').css({
diff --git a/kwant/graph/c_slicer/bucket_list.h b/kwant/graph/c_slicer/bucket_list.h
index 360dd6138e39de022cd7b67e59f1629cff96c86d..c95f24281fd4ff02e78b470ee511d2c58ef92baf 100644
--- a/kwant/graph/c_slicer/bucket_list.h
+++ b/kwant/graph/c_slicer/bucket_list.h
@@ -31,8 +31,8 @@ class bucket_list
 
  public:
   bucket_list(int _lower_bound, int _upper_bound,
-	      vector<list<int>::iterator > &_reference_list,
-	      const vector<int> &_index_list) :
+              vector<list<int>::iterator > &_reference_list,
+              const vector<int> &_index_list) :
     bucket(_upper_bound-_lower_bound+2, list<int>(0)),
     max_value(_lower_bound-1),
     lower_bound(_lower_bound), upper_bound(_upper_bound),
@@ -62,8 +62,8 @@ class bucket_list
       bucket[max_value - lower_bound + 1].pop_front();
 
       if(bucket[max_value - lower_bound + 1].empty()) {
-	while(bucket[--max_value - lower_bound + 1].empty())
-	  ;
+        while(bucket[--max_value - lower_bound + 1].empty())
+          ;
       }
     }
   }
@@ -114,7 +114,7 @@ class bucket_list
     }
     else if(bucket[max_value - lower_bound + 1].empty()) {
       while(bucket[--max_value - lower_bound + 1].empty())
-	;
+        ;
     }
   }
 
@@ -131,7 +131,7 @@ class bucket_list
     }
     else if(bucket[max_value - lower_bound + 1].empty()) {
       while(bucket[--max_value - lower_bound + 1].empty())
-	;
+        ;
     }
   }
 
@@ -150,7 +150,7 @@ class bucket_list
 
     if(bucket[max_value - lower_bound + 1].empty()) {
       while(bucket[--max_value - lower_bound + 1].empty())
-	;
+        ;
     }
   }
 
@@ -181,12 +181,12 @@ class double_bucket_list
 
  public:
   double_bucket_list(int _lower_bound1, int _upper_bound1,
-	      int _lower_bound2, int _upper_bound2,
-	      vector<list<int>::iterator > &_reference_list,
-	      const vector<int> &_index_list) :
+                     int _lower_bound2, int _upper_bound2,
+                     vector<list<int>::iterator > &_reference_list,
+                     const vector<int> &_index_list) :
     bucket(_upper_bound1-_lower_bound1+2,
-	   bucket_list(_lower_bound2, _upper_bound2,
-		       _reference_list, _index_list)),
+           bucket_list(_lower_bound2, _upper_bound2,
+           _reference_list, _index_list)),
     max_value(_lower_bound1-1),
     lower_bound(_lower_bound1), upper_bound(_upper_bound1),
     reference_list(_reference_list), index_list(_index_list)
@@ -214,8 +214,8 @@ class double_bucket_list
       bucket[max_value - lower_bound + 1].pop_front();
 
       if(bucket[max_value - lower_bound + 1].empty()) {
-	while(bucket[--max_value - lower_bound + 1].empty())
-	  ;
+        while(bucket[--max_value - lower_bound + 1].empty())
+          ;
       }
     }
   }
@@ -248,7 +248,7 @@ class double_bucket_list
   }
 
   inline void rearrange_back(int _old_key1, int _old_key2,
-			     int _new_key1, int _new_key2, int _data)
+                             int _new_key1, int _new_key2, int _data)
   {
     if(_old_key1 == _new_key1) {
       bucket[_old_key1 - lower_bound +1].rearrange_back(_old_key2, _new_key2, _data);
@@ -258,17 +258,17 @@ class double_bucket_list
       bucket[_new_key1 - lower_bound +1].push_back(_new_key2, _data);
 
       if(_new_key1 > max_value) {
-	max_value=_new_key1;
+        max_value=_new_key1;
       }
       else if(bucket[max_value - lower_bound + 1].empty()) {
-	while(bucket[--max_value - lower_bound + 1].empty())
-	  ;
+        while(bucket[--max_value - lower_bound + 1].empty())
+          ;
       }
     }
   }
 
   inline void rearrange_front(int _old_key1, int _old_key2,
-			      int _new_key1, int _new_key2, int _data)
+                              int _new_key1, int _new_key2, int _data)
   {
     if(_old_key1 == _new_key1) {
       bucket[_old_key1 - lower_bound +1].rearrange_front(_old_key2, _new_key2, _data);
@@ -278,17 +278,17 @@ class double_bucket_list
       bucket[_new_key1 - lower_bound +1].push_front(_new_key2, _data);
 
       if(_new_key1 > max_value) {
-	max_value=_new_key1;
+        max_value=_new_key1;
       }
       else if(bucket[max_value - lower_bound + 1].empty()) {
-	while(bucket[--max_value - lower_bound + 1].empty())
-	  ;
+        while(bucket[--max_value - lower_bound + 1].empty())
+          ;
       }
     }
   }
 
   inline void rearrange_randomly(int _old_key1, int _old_key2,
-				 int _new_key1, int _new_key2, int _data)
+                                 int _new_key1, int _new_key2, int _data)
   {
     if(rand()%2)
       rearrange_back(_old_key1, _old_key2, _new_key1, _new_key2, _data);