Support zero value in dimension for slice (#37313)

* support zero dim for slice op

* support zero dim Tensor in set_value op

* polish some debug log

paddle/fluid/operators/set_value_op.h

@@ -260,6 +260,9 @@ class SetValueKernel : public framework::OpKernel<T> {
       starts_indices[axis_index] = starts[i];
       ends_indices[axis_index] = ends[i];
       strides_indices[axis_index] = steps[i];
+      if (starts[i] == ends[i]) {  // slice is empty, data will not be changed
+        return;
+      }
     }
 
     out_e.stridedSlice(starts_indices, ends_indices, strides_indices)

paddle/fluid/operators/slice_utils.h

@@ -30,12 +30,20 @@ inline void CheckAndUpdateSliceAttrs(const framework::DDim in_dims,
                                      std::vector<T>* infer_flags = nullptr) {
   for (size_t i = 0; i < axes.size(); ++i) {
     T axis = axes[i];
-    T dim_value = in_dims[axis];
+    PADDLE_ENFORCE_LT(
+        axis, in_dims.size(),
+        platform::errors::InvalidArgument(
+            "The axis value should be less than the rank of input, "
+            "but received axes[%d] = %d, rank of input is %d.",
+            i, axis, in_dims.size()));
 
-    if (dim_value > 0) {
     if (infer_flags != nullptr && (*infer_flags)[i] == -1) {
       continue;
     }
+
+    T dim_value = in_dims[axis];
+
+    if (dim_value > 0) {
       T step = steps == nullptr ? 1 : (*steps)[i];
       PADDLE_ENFORCE_NE(
           step, 0, platform::errors::InvalidArgument(
@@ -51,7 +59,7 @@ inline void CheckAndUpdateSliceAttrs(const framework::DDim in_dims,
       if (step > 0) {
         start = std::min(start, dim_value);
         end = std::max(end, static_cast<T>(0));
-        PADDLE_ENFORCE_GT(
+        PADDLE_ENFORCE_GE(
             end, start,
             platform::errors::InvalidArgument(
                 "When step > 0, end should be greater than start, but "
@@ -63,7 +71,7 @@ inline void CheckAndUpdateSliceAttrs(const framework::DDim in_dims,
         // "end is -1" means contain the 0-th element of this axis.
         start = std::min(start, dim_value - 1);
         end = std::max(end, static_cast<T>(-1));
-        PADDLE_ENFORCE_GT(
+        PADDLE_ENFORCE_GE(
             start, end,
             platform::errors::InvalidArgument(
                 "When step < 0, start should be greater than end, but "
@@ -73,6 +81,9 @@ inline void CheckAndUpdateSliceAttrs(const framework::DDim in_dims,
 
       (*starts)[i] = start;
       (*ends)[i] = end;
+    } else if (dim_value == 0) {
+      (*starts)[i] = 0;
+      (*ends)[i] = 0;
     }
   }
 }
@@ -111,20 +122,22 @@ inline framework::DDim GetDecreasedDims(const framework::DDim slice_dims,
                                         const std::vector<T>& decrease_axes,
                                         std::vector<T>* infer_flags = nullptr) {
   framework::DDim decreased_dims(slice_dims);
+  std::vector<uint8_t> decrease_flag(slice_dims.size(), 0);
   if (decrease_axes.size() > 0) {
     for (size_t i = 0; i < decrease_axes.size(); ++i) {
       T axis = decrease_axes[i];
+      decrease_flag[axis] = 1;
       if (infer_flags && (*infer_flags)[i] != -1) {
-        PADDLE_ENFORCE_EQ(
-            decreased_dims[axis], 1,
-            platform::errors::InvalidArgument("decrease dim should be 1"));
+        PADDLE_ENFORCE_EQ(decreased_dims[axis], 1,
+                          platform::errors::InvalidArgument(
+                              "Decrease dim should be 1, but now received %d",
+                              decreased_dims[axis]));
       }
-      decreased_dims[axis] = 0;
     }
 
     std::vector<T> new_shape;
     for (int i = 0; i < decreased_dims.size(); ++i) {
-      if (decreased_dims[i] != 0) {
+      if (decrease_flag[i] == 0) {
         new_shape.push_back(decreased_dims[i]);
       }
     }

paddle/fluid/operators/strided_slice_op.h

@@ -77,10 +77,9 @@ static void StridedSliceOutDims(
       end_index = end_index + 1;
     }
 
-    bool zero_dim_condition =
-        ((stride_index < 0 && (start_index <= end_index)) ||
-         (stride_index > 0 && (start_index >= end_index)));
-    PADDLE_ENFORCE_EQ(zero_dim_condition, false,
+    bool neg_dim_condition = ((stride_index < 0 && (start_index < end_index)) ||
+                              (stride_index > 0 && (start_index > end_index)));
+    PADDLE_ENFORCE_EQ(neg_dim_condition, false,
                       platform::errors::InvalidArgument(
                           "The start index and end index are invalid for their "
                           "corresponding stride."));

python/paddle/fluid/tests/unittests/test_set_value_op.py

@@ -127,6 +127,14 @@ class TestSetValueItemSlice4(TestSetValueApi):
         self.data[0:, 1:2, :] = self.value
 
 
+class TestSetValueItemSlice5(TestSetValueApi):
+    def _call_setitem(self, x):
+        x[0:, 1:1, :] = self.value
+
+    def _get_answer(self):
+        self.data[0:, 1:1, :] = self.value
+
+
 class TestSetValueItemSliceInWhile(TestSetValueApi):
     def _call_setitem(self, x):
         def cond(i, x):

python/paddle/fluid/tests/unittests/test_var_base.py

@@ -568,10 +568,12 @@ class TestVarBase(unittest.TestCase):
         var14 = var[1:-1, 0:2, ::-1]
         var15 = var[::-1, ::-1, ::-1]
         var16 = var[-4:4]
+        var17 = var[:, 0, 0:0]
+        var18 = var[:, 1:1:2]
 
         vars = [
             var, var1, var2, var3, var4, var5, var6, var7, var8, var9, var10,
-            var11, var12, var13, var14, var15, var16
+            var11, var12, var13, var14, var15, var16, var17, var18
         ]
         local_out = [var.numpy() for var in vars]
 
@@ -600,6 +602,8 @@ class TestVarBase(unittest.TestCase):
         self.assertTrue(
             np.array_equal(local_out[15], tensor_array[::-1, ::-1, ::-1]))
         self.assertTrue(np.array_equal(local_out[16], tensor_array[-4:4]))
+        self.assertTrue(np.array_equal(local_out[17], tensor_array[:, 0, 0:0]))
+        self.assertTrue(np.array_equal(local_out[18], tensor_array[:, 1:1:2]))
 
     def _test_slice_for_tensor_attr(self):
         tensor_array = np.array(