enhance/add lod check (#7439)

Author: Superjomn

paddle/framework/lod_tensor.cc

@@ -135,6 +135,65 @@ bool operator==(const LoD &a, const LoD &b) {
   return true;
 }
 
+bool CheckLoD(const LoD &in, int tensor_height) {
+  if (in.empty()) return true;
+  for (const auto &level : in) {
+    // check: there should be more than 2 offsets existing in each level.
+    if (level.size() < 2) return false;
+    // check: the first offset(the begin offset) of each level should be 0.
+    if (level.front() != 0) return false;
+    // check: all the offsets in a level should be ascending(no same items
+    // allows).
+    if (!std::is_sorted(level.begin(), level.begin(), [](size_t a, size_t b) {
+          if (a < b) return true;
+          return false;
+        })) {
+      LOG(INFO) << "ascending error";
+      return false;
+    }
+  }
+  // check: the lowest level's last offset should equals `tensor_height` if
+  //        tensor_height>0.
+  if (tensor_height > 0 && (size_t)tensor_height != in.back().back())
+    return false;
+
+  // check: the higher level's last offset should equals the lower level's
+  // size-1.
+  // NOTE LoD store the levels from top to bottom, so the higher level goes
+  // first.
+  for (size_t level = 0; level < in.size() - 1; level++) {
+    if (in[level].back() != in[level + 1].size() - 1) return false;
+  }
+  return true;
+}
+
+bool CheckAbsLoD(const LoD &in, int tensor_height) {
+  if (in.empty()) return true;
+  for (const auto &level : in) {
+    // check: all the offsets in a level should be ascending(no same items
+    // allows).
+    if (!std::is_sorted(level.begin(), level.begin(), [](size_t a, size_t b) {
+          if (a < b) return true;
+          return false;
+        })) {
+      return false;
+    }
+
+    // check: there should be more than 2 offsets existing in each level.
+    if (level.size() < 2) return false;
+
+    // check: the first offset of each level should be 0, and the last should be
+    // the same(the height of underlying tensor).
+    if (level.front() != 0) return false;
+    if (tensor_height < 0) {
+      tensor_height = level.back();
+    } else if ((size_t)tensor_height != level.back()) {
+      return false;
+    }
+  }
+  return true;
+}
+
 using LoDAndOffset = std::pair<LoD, std::pair<size_t, size_t>>;
 LoDAndOffset GetSubLoDAndAbsoluteOffset(const LoD &lod, size_t start_idx,
                                         size_t end_idx, size_t start_level) {

paddle/framework/lod_tensor.h

@@ -71,6 +71,38 @@ LoD ToAbsOffset(const LoD& in);
 
 bool operator==(const LoD& a, const LoD& b);
 
+/*
+ * Check whether this lod's format is valid.
+ *
+ * ATTENTION:
+ *   - Empty lod is treated as valid.
+ *
+ * It will check two things:
+ *
+ *  1. all the offsets in a level should be ascending(no same items allows).
+ *  2. there should be more than 2 offsets existing in each level.
+ *  3. the higher level's last offset should equals the lower level's size-1.
+ *  4. the first offset(the begin offset) of each level should be 0.
+ *  5. the lowest level's last offset should equals `tensor_height` if
+ * tensor_height>0.
+ */
+
+bool CheckLoD(const LoD& in, int tensor_height = -1);
+/*
+ * Check whether this absolute lod's format is valid.
+ *
+ * ATTENTION:
+ *   - Empty lod is treated as valid.
+ *
+ * It will check two things:
+ *  1. all the offsets in a level should be ascending(no same items allows)
+ *  2. there should be more than 2 offsets existing in each level.
+ *  3. the first offset of each level should be 0, and the last should be the
+ *     same(the height of underlying tensor) or `tensor_height` if
+ *     tensor_height>0.
+ */
+bool CheckAbsLoD(const LoD& in, int tensor_height = -1);
+
 /*
  * LoDTensor (Level of details Tensor)
  * see https://en.wikipedia.org/wiki/Level_of_details for reference.

paddle/framework/lod_tensor_test.cc

@@ -37,36 +37,6 @@ namespace framework {
 
 const int kLodTensorSize = 20 * 128;
 
-class LoDTensorTester : public ::testing::Test {
- public:
-  virtual void SetUp() override {
-    // tensor's batch_size: 30
-    // 3 levels
-    // 0 10 20
-    // 0 5 10 15 20
-    // 0 2 5 7 10 12 15 20
-    LoD lod;
-    lod.push_back(std::vector<size_t>{0, 2, 3});
-    lod.push_back(std::vector<size_t>{0, 2, 5, 8});
-    lod.push_back(std::vector<size_t>{0, 2, 5, 7, 10, 12, 15, 17, 20});
-
-    ASSERT_EQ(lod.size(), 3UL);
-
-    lod_tensor_.Resize({20 /*batch size*/, 128 /*dim*/});
-    // malloc memory
-    float* dst_ptr = lod_tensor_.mutable_data<float>(place);
-    for (int i = 0; i < kLodTensorSize; ++i) {
-      dst_ptr[i] = i;
-    }
-
-    lod_tensor_.set_lod(lod);
-  }
-
- protected:
-  platform::CPUPlace place;
-  LoDTensor lod_tensor_;
-};
-
 TEST(LodExpand, test) {
   LoD lod{{0, 2}};
   LoDTensor tensor;
@@ -144,5 +114,53 @@ TEST(LoD, ToAbsOffset) {
   EXPECT_EQ(abs_lod, expected);
 }
 
+TEST(LoD, CheckLoD) {
+  LoD relative_lod;
+  relative_lod.push_back(std::vector<size_t>({0, 2}));
+  relative_lod.push_back(std::vector<size_t>({0, 1, 3}));
+  relative_lod.push_back(std::vector<size_t>({0, 2, 4, 5}));
+
+  // check compatible
+  ASSERT_TRUE(CheckLoD(relative_lod));
+  relative_lod[1].back()++;
+  ASSERT_FALSE(CheckLoD(relative_lod));
+  relative_lod[1].back()--;  // recover it
+
+  // check empty
+  LoD empty_lod;
+  ASSERT_TRUE(CheckLoD(empty_lod));
+
+  // check less than 2 offsets in a level
+  LoD some_lod0;
+  some_lod0.push_back(std::vector<size_t>({0}));
+  ASSERT_FALSE(CheckLoD(some_lod0));
+
+  // check with underlying tensor storage.
+  ASSERT_TRUE(CheckLoD(relative_lod, 5));
+  ASSERT_FALSE(CheckLoD(relative_lod, 9));
+}
+
+TEST(LoD, CheckAbsLoD) {
+  LoD relative_lod;
+  relative_lod.push_back(std::vector<size_t>({0, 2}));
+  relative_lod.push_back(std::vector<size_t>({0, 1, 3}));
+  relative_lod.push_back(std::vector<size_t>({0, 2, 4, 5}));
+
+  auto abs_lod = ToAbsOffset(relative_lod);
+
+  ASSERT_TRUE(CheckAbsLoD(abs_lod));
+
+  // check less than 2 offsets in a level.
+
+  // check the last item should be compatible with tensor height.
+  abs_lod.back().back()++;
+  ASSERT_FALSE(CheckAbsLoD(abs_lod));
+  abs_lod.back().back()--;  // restore
+
+  // check less than 2 offsets in a lod.
+  LoD abs_lod0;
+  abs_lod0.push_back(std::vector<size_t>({0}));
+  ASSERT_FALSE(CheckAbsLoD(abs_lod0));
+}
 }  // namespace framework
 }  // namespace paddle