diff --git a/c_api/AutoTune_c.cpp b/c_api/AutoTune_c.cpp
index 70be977efc..008d6f8482 100644
--- a/c_api/AutoTune_c.cpp
+++ b/c_api/AutoTune_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/AutoTune_c.h b/c_api/AutoTune_c.h
index 3709a3eb39..908f355a4d 100644
--- a/c_api/AutoTune_c.h
+++ b/c_api/AutoTune_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/AuxIndexStructures_c.cpp b/c_api/AuxIndexStructures_c.cpp
index f8bb373fde..c1ef0dc8c0 100644
--- a/c_api/AuxIndexStructures_c.cpp
+++ b/c_api/AuxIndexStructures_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -14,14 +13,13 @@
 #include "macros_impl.h"
 #include <iostream>
 
-extern "C" {
-
 using faiss::BufferList;
 using faiss::IDSelector;
 using faiss::IDSelectorBatch;
 using faiss::IDSelectorRange;
 using faiss::RangeSearchResult;
 using faiss::RangeSearchPartialResult;
+using faiss::RangeQueryResult;
 
 DEFINE_GETTER(RangeSearchResult, size_t, nq)
 
@@ -140,6 +138,17 @@ int faiss_BufferList_copy_range(
     } CATCH_AND_HANDLE
 }
 
+DEFINE_GETTER(RangeQueryResult, idx_t, qno)
+DEFINE_GETTER(RangeQueryResult, size_t, nres)
+DEFINE_GETTER_PERMISSIVE(RangeQueryResult, FaissRangeSearchPartialResult*, pres)
+
+int faiss_RangeQueryResult_add(FaissRangeQueryResult* qr, float dis, idx_t id) {
+    try {
+        reinterpret_cast<RangeQueryResult*>(qr)->add(dis, id);
+        return 0;
+    } CATCH_AND_HANDLE
+}
+
 DEFINE_GETTER_PERMISSIVE(RangeSearchPartialResult, FaissRangeSearchResult*, res)
 
 int faiss_RangeSearchPartialResult_new(
@@ -170,38 +179,15 @@ int faiss_RangeSearchPartialResult_set_lims(
     } CATCH_AND_HANDLE
 }
 
-/// called by range_search after do_allocation
-int faiss_RangeSearchPartialResult_set_result(
-    FaissRangeSearchPartialResult* res, int incremental) {
-    try {
-        reinterpret_cast<RangeSearchPartialResult*>(res)->set_result(
-            static_cast<bool>(incremental));
-        return 0;
-    } CATCH_AND_HANDLE
-}
-
-DEFINE_GETTER_SUBCLASS(QueryResult, RangeSearchPartialResult, idx_t, qno)
-DEFINE_GETTER_SUBCLASS(QueryResult, RangeSearchPartialResult, size_t, nres)
-DEFINE_GETTER_SUBCLASS_PERMISSIVE(QueryResult, RangeSearchPartialResult, FaissRangeSearchPartialResult*, pres)
-
 int faiss_RangeSearchPartialResult_new_result(
-    FaissRangeSearchPartialResult* res, idx_t qno, FaissQueryResult** qr) {
+    FaissRangeSearchPartialResult* res, idx_t qno, FaissRangeQueryResult** qr) {
 
     try {
-        RangeSearchPartialResult::QueryResult* q = 
+        auto q = 
             &reinterpret_cast<RangeSearchPartialResult*>(res)->new_result(qno);
         if (qr) {
-            *qr = reinterpret_cast<FaissQueryResult*>(q);
+            *qr = reinterpret_cast<FaissRangeQueryResult*>(&q);
         }
         return 0;
     } CATCH_AND_HANDLE
 }
-
-int faiss_QueryResult_add(FaissQueryResult* qr, float dis, idx_t id) {
-    try {
-        reinterpret_cast<RangeSearchPartialResult::QueryResult*>(qr)->add(dis, id);
-        return 0;
-    } CATCH_AND_HANDLE
-}
-
-}
diff --git a/c_api/AuxIndexStructures_c.h b/c_api/AuxIndexStructures_c.h
index dc3c29e22a..b7cbad9e39 100644
--- a/c_api/AuxIndexStructures_c.h
+++ b/c_api/AuxIndexStructures_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -103,6 +102,15 @@ int faiss_BufferList_copy_range(
 /// the entries in the buffers are split per query
 FAISS_DECLARE_CLASS(RangeSearchPartialResult)
 
+/// result structure for a single query
+FAISS_DECLARE_CLASS(RangeQueryResult)
+FAISS_DECLARE_GETTER(RangeQueryResult, idx_t, qno)
+FAISS_DECLARE_GETTER(RangeQueryResult, size_t, nres)
+FAISS_DECLARE_GETTER(RangeQueryResult, FaissRangeSearchPartialResult*, pres)
+
+int faiss_RangeQueryResult_add(FaissRangeQueryResult* qr, float dis, idx_t id);
+
+
 FAISS_DECLARE_GETTER(RangeSearchPartialResult, FaissRangeSearchResult*, res)
 
 int faiss_RangeSearchPartialResult_new(
@@ -115,20 +123,8 @@ int faiss_RangeSearchPartialResult_finalize(
 int faiss_RangeSearchPartialResult_set_lims(
     FaissRangeSearchPartialResult* res);
 
-/// called by range_search after do_allocation
-int faiss_RangeSearchPartialResult_set_result(
-    FaissRangeSearchPartialResult* res, int incremental);
-
-/// result structure for a single query
-FAISS_DECLARE_CLASS(QueryResult)
-FAISS_DECLARE_GETTER(QueryResult, idx_t, qno)
-FAISS_DECLARE_GETTER(QueryResult, size_t, nres)
-FAISS_DECLARE_GETTER(QueryResult, FaissRangeSearchPartialResult*, pres)
-
 int faiss_RangeSearchPartialResult_new_result(
-    FaissRangeSearchPartialResult* res, idx_t qno, FaissQueryResult** qr);
-
-int faiss_QueryResult_add(FaissQueryResult* qr, float dis, idx_t id);
+    FaissRangeSearchPartialResult* res, idx_t qno, FaissRangeQueryResult** qr);
 
 #ifdef __cplusplus
 }
diff --git a/c_api/Clustering_c.cpp b/c_api/Clustering_c.cpp
index f7951a5e99..1687ed1e45 100644
--- a/c_api/Clustering_c.cpp
+++ b/c_api/Clustering_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/Clustering_c.h b/c_api/Clustering_c.h
index 768e434b35..75f25ba4f5 100644
--- a/c_api/Clustering_c.h
+++ b/c_api/Clustering_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/IndexFlat_c.cpp b/c_api/IndexFlat_c.cpp
index ba3454ceb4..4b741922e8 100644
--- a/c_api/IndexFlat_c.cpp
+++ b/c_api/IndexFlat_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/IndexFlat_c.h b/c_api/IndexFlat_c.h
index 4f45c98553..072ba7dcf3 100644
--- a/c_api/IndexFlat_c.h
+++ b/c_api/IndexFlat_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/IndexIVFFlat_c.cpp b/c_api/IndexIVFFlat_c.cpp
index 3930f53e8b..a93e22e3b7 100644
--- a/c_api/IndexIVFFlat_c.cpp
+++ b/c_api/IndexIVFFlat_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/IndexIVFFlat_c.h b/c_api/IndexIVFFlat_c.h
index a8b27f17f2..84e2d79b36 100644
--- a/c_api/IndexIVFFlat_c.h
+++ b/c_api/IndexIVFFlat_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/IndexIVF_c.cpp b/c_api/IndexIVF_c.cpp
index 53fcaa3938..92469a16e5 100644
--- a/c_api/IndexIVF_c.cpp
+++ b/c_api/IndexIVF_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -80,12 +79,12 @@ int faiss_IndexIVF_make_direct_map(FaissIndexIVF* index,
 }
 
 double faiss_IndexIVF_imbalance_factor (const FaissIndexIVF* index) {
-    return reinterpret_cast<const IndexIVF*>(index)->imbalance_factor();
+    return reinterpret_cast<const IndexIVF*>(index)->invlists->imbalance_factor();
 }
 
 /// display some stats about the inverted lists
 void faiss_IndexIVF_print_stats (const FaissIndexIVF* index) {
-    reinterpret_cast<const IndexIVF*>(index)->print_stats();
+    reinterpret_cast<const IndexIVF*>(index)->invlists->print_stats();
 }
 
 void faiss_IndexIVFStats_reset(FaissIndexIVFStats* stats) {
diff --git a/c_api/IndexIVF_c.h b/c_api/IndexIVF_c.h
index 0d2459d8ed..c35def97cf 100644
--- a/c_api/IndexIVF_c.h
+++ b/c_api/IndexIVF_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -106,10 +105,13 @@ size_t faiss_IndexIVF_get_list_size(const FaissIndexIVF* index,
 int faiss_IndexIVF_make_direct_map(FaissIndexIVF* index,
     int new_maintain_direct_map);
 
-/// 1= perfectly balanced, >1: imbalanced
+/** Check the inverted lists' imbalance factor.
+ *
+ * 1= perfectly balanced, >1: imbalanced
+ */
 double faiss_IndexIVF_imbalance_factor (const FaissIndexIVF* index);
 
-/// display some stats about the inverted lists
+/// display some stats about the inverted lists of the index
 void faiss_IndexIVF_print_stats (const FaissIndexIVF* index);
 
 
diff --git a/c_api/IndexLSH_c.cpp b/c_api/IndexLSH_c.cpp
index 7e29ac852c..39a348f807 100644
--- a/c_api/IndexLSH_c.cpp
+++ b/c_api/IndexLSH_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/IndexLSH_c.h b/c_api/IndexLSH_c.h
index 136b4dd98c..4a3dab418d 100644
--- a/c_api/IndexLSH_c.h
+++ b/c_api/IndexLSH_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/IndexShards_c.cpp b/c_api/IndexShards_c.cpp
new file mode 100644
index 0000000000..e66aeb7ed0
--- /dev/null
+++ b/c_api/IndexShards_c.cpp
@@ -0,0 +1,44 @@
+#include "IndexShards_c.h"
+#include "IndexShards.h"
+#include "macros_impl.h"
+
+using faiss::Index;
+using faiss::IndexShards;
+
+DEFINE_GETTER(IndexShards, int, own_fields)
+DEFINE_SETTER(IndexShards, int, own_fields)
+
+DEFINE_GETTER(IndexShards, int, successive_ids)
+DEFINE_SETTER(IndexShards, int, successive_ids)
+
+int faiss_IndexShards_new(FaissIndexShards** p_index, idx_t d) {
+    try {
+        auto out = new IndexShards(d);
+        *p_index = reinterpret_cast<FaissIndexShards*>(out);
+    } CATCH_AND_HANDLE
+}
+
+int faiss_IndexShards_new_with_options(FaissIndexShards** p_index, idx_t d, int threaded, int successive_ids) {
+    try {
+        auto out = new IndexShards(d, static_cast<bool>(threaded), static_cast<bool>(successive_ids));
+        *p_index = reinterpret_cast<FaissIndexShards*>(out);
+    } CATCH_AND_HANDLE
+}
+
+int faiss_IndexShards_add_shard(FaissIndexShards* index, FaissIndex* shard) {
+    try {
+        reinterpret_cast<IndexShards*>(index)->add_shard(
+            reinterpret_cast<Index*>(shard));
+    } CATCH_AND_HANDLE
+}
+
+int faiss_IndexShards_sync_with_shard_indexes(FaissIndexShards* index) {
+    try {
+        reinterpret_cast<IndexShards*>(index)->sync_with_shard_indexes();
+    } CATCH_AND_HANDLE
+}
+
+FaissIndex* faiss_IndexShards_at(FaissIndexShards* index, int i) {
+    auto shard = reinterpret_cast<IndexShards*>(index)->at(i);
+    return reinterpret_cast<FaissIndex*>(shard);
+}
diff --git a/c_api/IndexShards_c.h b/c_api/IndexShards_c.h
new file mode 100644
index 0000000000..7e6a30b2a9
--- /dev/null
+++ b/c_api/IndexShards_c.h
@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// Copyright 2004-present Facebook. All Rights Reserved.
+// -*- c++ -*-
+
+#ifndef INDEXSHARDS_C_H
+#define INDEXSHARDS_C_H
+
+#include "faiss_c.h"
+#include "Index_c.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Index that concatenates the results from several sub-indexes
+ */
+FAISS_DECLARE_CLASS_INHERITED(IndexShards, Index)
+
+FAISS_DECLARE_GETTER_SETTER(IndexShards, int, own_fields)
+FAISS_DECLARE_GETTER_SETTER(IndexShards, int, successive_ids)
+
+int faiss_IndexShards_new(FaissIndexShards** p_index, idx_t d);
+
+int faiss_IndexShards_new_with_options(FaissIndexShards** p_index, idx_t d, int threaded, int successive_ids);
+
+int faiss_IndexShards_add_shard(FaissIndexShards* index, FaissIndex* shard);
+
+/// update metric_type and ntotal
+int faiss_IndexShards_sync_with_shard_indexes(FaissIndexShards* index);
+
+FaissIndex* faiss_IndexShards_at(FaissIndexShards* index, int i);
+
+#ifdef __cplusplus
+}
+#endif
+#endif
\ No newline at end of file
diff --git a/c_api/Index_c.cpp b/c_api/Index_c.cpp
index e1e426253e..a0773e9ae9 100644
--- a/c_api/Index_c.cpp
+++ b/c_api/Index_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/Index_c.h b/c_api/Index_c.h
index be4787f428..1b456ad8f4 100644
--- a/c_api/Index_c.h
+++ b/c_api/Index_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/Makefile b/c_api/Makefile
index 5795a1ddad..b3a3061b7c 100644
--- a/c_api/Makefile
+++ b/c_api/Makefile
@@ -1,7 +1,6 @@
-# Copyright (c) 2015-present, Facebook, Inc.
-# All rights reserved.
+# Copyright (c) Facebook, Inc. and its affiliates.
 #
-# This source code is licensed under the BSD+Patents license found in the
+# This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
 
 .SUFFIXES: .cpp .o
@@ -13,8 +12,9 @@ DEBUGFLAG=-DNDEBUG # no debugging
 
 LIBNAME=libfaiss
 CLIBNAME=libfaiss_c
-LIBCOBJ=error_impl.o Index_c.o IndexFlat_c.o Clustering_c.o AuxIndexStructures_c.o \
-	AutoTune_c.o IndexIVF_c.o IndexIVFFlat_c.o IndexLSH_c.o index_io_c.o MetaIndexes_c.o
+LIBCOBJ=error_impl.o Index_c.o IndexFlat_c.o Clustering_c.o AutoTune_c.o \
+	AuxIndexStructures_c.o IndexIVF_c.o IndexIVFFlat_c.o IndexLSH_c.o \
+	index_io_c.o MetaIndexes_c.o IndexShards_c.o
 
 # Build static and shared object files by default
 all: $(CLIBNAME).a $(CLIBNAME).$(SHAREDEXT)
@@ -59,6 +59,9 @@ IndexIVFFlat_c.o: IndexIVFFlat_c.cpp IndexIVFFlat_c.h ../IndexIVFFlat.h macros_i
 IndexLSH_c.o: CXXFLAGS += -I.. $(DEBUGFLAG)
 IndexLSH_c.o: IndexLSH_c.cpp IndexLSH_c.h ../IndexLSH.h macros_impl.h
 
+IndexShards_c.o: CXXFLAGS += -I.. $(DEBUGFLAG)
+IndexShards_c.o: IndexShards_c.cpp IndexShards_c.h ../Index.h ../IndexShards.h macros_impl.h
+
 Clustering_c.o: CXXFLAGS += -I.. $(DEBUGFLAG)
 Clustering_c.o: Clustering_c.cpp Clustering_c.h ../Clustering.h macros_impl.h
 
diff --git a/c_api/MetaIndexes_c.cpp b/c_api/MetaIndexes_c.cpp
index b02a9680a2..d1a6191932 100644
--- a/c_api/MetaIndexes_c.cpp
+++ b/c_api/MetaIndexes_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -16,7 +15,6 @@
 using faiss::Index;
 using faiss::IndexIDMap;
 using faiss::IndexIDMap2;
-using faiss::IndexShards;
 
 DEFINE_GETTER(IndexIDMap, int, own_fields)
 DEFINE_SETTER(IndexIDMap, int, own_fields)
@@ -49,58 +47,3 @@ int faiss_IndexIDMap2_construct_rev_map(FaissIndexIDMap2* index) {
     } CATCH_AND_HANDLE
 }
 
-DEFINE_GETTER(IndexShards, int, own_fields)
-DEFINE_SETTER(IndexShards, int, own_fields)
-
-DEFINE_GETTER(IndexShards, int, threaded)
-DEFINE_SETTER(IndexShards, int, threaded)
-
-DEFINE_GETTER(IndexShards, int, successive_ids)
-DEFINE_SETTER(IndexShards, int, successive_ids)
-
-int faiss_IndexShards_new(FaissIndexShards** p_index, idx_t d) {
-    try {
-        auto out = new IndexShards(d);
-        *p_index = reinterpret_cast<FaissIndexShards*>(out);
-    } CATCH_AND_HANDLE
-}
-
-int faiss_IndexShards_new_with_options(FaissIndexShards** p_index, idx_t d, int threaded, int successive_ids) {
-    try {
-        auto out = new IndexShards(d, static_cast<bool>(threaded), static_cast<bool>(successive_ids));
-        *p_index = reinterpret_cast<FaissIndexShards*>(out);
-    } CATCH_AND_HANDLE
-}
-
-/** get a pointer to the index' shards (the `shard_indexes` field). The
- * outputs of this function become invalid after any operation that can modify the index.
- * 
- * @param index   opaque pointer to index object
- * @param p_shard_indexes    output, the pointer to the beginning of `shard_indexes`.
- * @param p_size  output, the current length of `shard_indexes`.
- */
-void faiss_IndexShards_shard_indexes(FaissIndexShards* index, FaissIndex** p_shard_indexes, size_t* p_size) {
-    auto idx = reinterpret_cast<IndexShards*>(index);
-    if (p_shard_indexes)
-        *p_shard_indexes = reinterpret_cast<FaissIndex*>(idx->shard_indexes.data());
-    if (p_size)
-        *p_size = idx->shard_indexes.size();
-}
-
-int faiss_IndexShards_add_shard(FaissIndexShards* index, FaissIndex* shard) {
-    try {
-        reinterpret_cast<IndexShards*>(index)->add_shard(
-            reinterpret_cast<Index*>(shard));
-    } CATCH_AND_HANDLE
-}
-
-int faiss_IndexShards_sync_with_shard_indexes(FaissIndexShards* index) {
-    try {
-        reinterpret_cast<IndexShards*>(index)->sync_with_shard_indexes();
-    } CATCH_AND_HANDLE
-}
-
-FaissIndex* faiss_IndexShards_at(FaissIndexShards* index, int i) {
-    auto shard = reinterpret_cast<IndexShards*>(index)->at(i);
-    return reinterpret_cast<FaissIndex*>(shard);
-}
diff --git a/c_api/MetaIndexes_c.h b/c_api/MetaIndexes_c.h
index 2ab4ed6c82..d07bb3f906 100644
--- a/c_api/MetaIndexes_c.h
+++ b/c_api/MetaIndexes_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -44,34 +43,6 @@ int faiss_IndexIDMap2_new(FaissIndexIDMap2** p_index, FaissIndex* index);
 /// make the rev_map from scratch
 int faiss_IndexIDMap2_construct_rev_map(FaissIndexIDMap2* index);
 
-/** Index that concatenates the results from several sub-indexes
- */
-FAISS_DECLARE_CLASS_INHERITED(IndexShards, Index)
-
-FAISS_DECLARE_GETTER_SETTER(IndexShards, int, own_fields)
-FAISS_DECLARE_GETTER_SETTER(IndexShards, int, threaded)
-FAISS_DECLARE_GETTER_SETTER(IndexShards, int, successive_ids)
-
-int faiss_IndexShards_new(FaissIndexShards** p_index, idx_t d);
-
-int faiss_IndexShards_new_with_options(FaissIndexShards** p_index, idx_t d, int threaded, int successive_ids);
-
-/** get a pointer to the index' shards (the `shard_indexes` field). The
- * outputs of this function become invalid after any operation that can modify the index.
- * 
- * @param index   opaque pointer to index object
- * @param p_shard_indexes    output, the pointer to the beginning of `shard_indexes`.
- * @param p_size  output, the current length of `shard_indexes`.
- */
-void faiss_IndexShards_shard_indexes(FaissIndexShards* index, FaissIndex** p_shard_indexes, size_t* p_size);
-
-int faiss_IndexShards_add_shard(FaissIndexShards* index, FaissIndex* shard);
-
-/// update metric_type and ntotal
-int faiss_IndexShards_sync_with_shard_indexes(FaissIndexShards* index);
-
-FaissIndex* faiss_IndexShards_at(FaissIndexShards* index, int i);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/c_api/error_c.h b/c_api/error_c.h
index 6fd81cd464..5aa5664feb 100644
--- a/c_api/error_c.h
+++ b/c_api/error_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -16,10 +15,16 @@
 extern "C" {
 #endif
 
+/// An error code which depends on the exception thrown from the previous 
+/// operation. See `faiss_get_last_error` to retrieve the error message.
 typedef enum FaissErrorCode {
+    /// No error
     OK = 0,
+    /// Any exception other than Faiss or standard C++ library exceptions
     UNKNOWN_EXCEPT = -1,
+    /// Faiss library exception
     FAISS_EXCEPT = -2,
+    /// Standard C++ library exception
     STD_EXCEPT = -4
 } FaissErrorCode;
 
diff --git a/c_api/error_impl.cpp b/c_api/error_impl.cpp
index 807670d54d..25793eb0e8 100644
--- a/c_api/error_impl.cpp
+++ b/c_api/error_impl.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/error_impl.h b/c_api/error_impl.h
index 8f72d3e8cc..b44254ad94 100644
--- a/c_api/error_impl.h
+++ b/c_api/error_impl.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/example_c.c b/c_api/example_c.c
index 5f4e90695d..f3d50e3af6 100644
--- a/c_api/example_c.c
+++ b/c_api/example_c.c
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/faiss_c.h b/c_api/faiss_c.h
index 5c9aaf2cea..3305604a85 100644
--- a/c_api/faiss_c.h
+++ b/c_api/faiss_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuAutoTune_c.cpp b/c_api/gpu/GpuAutoTune_c.cpp
index 1319b38dae..7336d5d7d3 100644
--- a/c_api/gpu/GpuAutoTune_c.cpp
+++ b/c_api/gpu/GpuAutoTune_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuAutoTune_c.h b/c_api/gpu/GpuAutoTune_c.h
index cb989d2528..5dbd15c977 100644
--- a/c_api/gpu/GpuAutoTune_c.h
+++ b/c_api/gpu/GpuAutoTune_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuClonerOptions_c.cpp b/c_api/gpu/GpuClonerOptions_c.cpp
index ac7772e54f..c61fc5e34c 100644
--- a/c_api/gpu/GpuClonerOptions_c.cpp
+++ b/c_api/gpu/GpuClonerOptions_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuClonerOptions_c.h b/c_api/gpu/GpuClonerOptions_c.h
index 7b6817b374..94ff403e7a 100644
--- a/c_api/gpu/GpuClonerOptions_c.h
+++ b/c_api/gpu/GpuClonerOptions_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuIndex_c.cpp b/c_api/gpu/GpuIndex_c.cpp
index 96c814f70e..bdef82766e 100644
--- a/c_api/gpu/GpuIndex_c.cpp
+++ b/c_api/gpu/GpuIndex_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuIndex_c.h b/c_api/gpu/GpuIndex_c.h
index 2f56738ccc..664c76101f 100644
--- a/c_api/gpu/GpuIndex_c.h
+++ b/c_api/gpu/GpuIndex_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuIndicesOptions_c.h b/c_api/gpu/GpuIndicesOptions_c.h
index e52bb55e25..6a49773bc6 100644
--- a/c_api/gpu/GpuIndicesOptions_c.h
+++ b/c_api/gpu/GpuIndicesOptions_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuResources_c.cpp b/c_api/gpu/GpuResources_c.cpp
index 2a375758e6..3f6525125d 100644
--- a/c_api/gpu/GpuResources_c.cpp
+++ b/c_api/gpu/GpuResources_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/GpuResources_c.h b/c_api/gpu/GpuResources_c.h
index 980bfa7101..bb9cefde36 100644
--- a/c_api/gpu/GpuResources_c.h
+++ b/c_api/gpu/GpuResources_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/Makefile b/c_api/gpu/Makefile
index 2fcc785e0a..a2c87b9832 100644
--- a/c_api/gpu/Makefile
+++ b/c_api/gpu/Makefile
@@ -1,7 +1,6 @@
-# Copyright (c) 2015-present, Facebook, Inc.
-# All rights reserved.
+# Copyright (c) Facebook, Inc. and its affiliates.
 #
-# This source code is licensed under the BSD+Patents license found in the
+# This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
 
 .SUFFIXES: .cpp .o
diff --git a/c_api/gpu/StandardGpuResources_c.cpp b/c_api/gpu/StandardGpuResources_c.cpp
index d25da77877..84afb027eb 100644
--- a/c_api/gpu/StandardGpuResources_c.cpp
+++ b/c_api/gpu/StandardGpuResources_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -36,12 +35,6 @@ int faiss_StandardGpuResources_setTempMemory(FaissStandardGpuResources* res, siz
     } CATCH_AND_HANDLE
 }
 
-int faiss_StandardGpuResources_setTempMemoryFraction(FaissStandardGpuResources* res, float fraction) {
-    try {
-        reinterpret_cast<StandardGpuResources*>(res)->setTempMemoryFraction(fraction);
-    } CATCH_AND_HANDLE
-}
-
 int faiss_StandardGpuResources_setPinnedMemory(FaissStandardGpuResources* res, size_t size) {
     try {
         reinterpret_cast<StandardGpuResources*>(res)->setPinnedMemory(size);
diff --git a/c_api/gpu/StandardGpuResources_c.h b/c_api/gpu/StandardGpuResources_c.h
index c87a1600f5..f9a3c854f0 100644
--- a/c_api/gpu/StandardGpuResources_c.h
+++ b/c_api/gpu/StandardGpuResources_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
@@ -37,10 +36,6 @@ int faiss_StandardGpuResources_noTempMemory(FaissStandardGpuResources*);
 /// all devices as temporary memory
 int faiss_StandardGpuResources_setTempMemory(FaissStandardGpuResources*, size_t size);
 
-/// Specify that we wish to use a certain fraction of memory on
-/// all devices as temporary memory
-int faiss_StandardGpuResources_setTempMemoryFraction(FaissStandardGpuResources*, float fraction);
-
 /// Set amount of pinned memory to allocate, for async GPU <-> CPU
 /// transfers
 int faiss_StandardGpuResources_setPinnedMemory(FaissStandardGpuResources*, size_t size);
diff --git a/c_api/gpu/example_gpu_c.c b/c_api/gpu/example_gpu_c.c
index 9121df79cc..c8122884fb 100644
--- a/c_api/gpu/example_gpu_c.c
+++ b/c_api/gpu/example_gpu_c.c
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/gpu/macros_impl.h b/c_api/gpu/macros_impl.h
index bef971fe79..3f6ea5844a 100644
--- a/c_api/gpu/macros_impl.h
+++ b/c_api/gpu/macros_impl.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/index_io_c.cpp b/c_api/index_io_c.cpp
index 40aa5017cc..479045e1fb 100644
--- a/c_api/index_io_c.cpp
+++ b/c_api/index_io_c.cpp
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/index_io_c.h b/c_api/index_io_c.h
index 68f4c1ccdb..f20ce2e644 100644
--- a/c_api/index_io_c.h
+++ b/c_api/index_io_c.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
diff --git a/c_api/macros_impl.h b/c_api/macros_impl.h
index dd778eb8f1..af07938018 100644
--- a/c_api/macros_impl.h
+++ b/c_api/macros_impl.h
@@ -1,8 +1,7 @@
 /**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
- * This source code is licensed under the BSD+Patents license found in the
+ * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */