Fix bug in reduce_ops when keep_dim is true. (#2906)

test=develop

lite/kernels/x86/reduce_op_function.h

@@ -63,7 +63,19 @@ void ReduceFunctor(const lite::Tensor& input,
     auto out = EigenScalar<T>::From(output);
     functor(&x, &out, reduce_dim);
   } else {
-    auto out = EigenTensor<T, (D - R_D)>::From(*output, output->dims());
+    std::vector<DDim::value_type> out_dims;
+    if (keep_dim) {
+      // Construct the squeezed dims.
+      const int kDelFlag = -2;
+      out_dims = output->dims().Vectorize();
+      for (size_t i = 0; i < dims.size(); ++i) {
+        out_dims[reduce_dim[i]] = kDelFlag;
+      }
+      out_dims.erase(remove(out_dims.begin(), out_dims.end(), kDelFlag),
+                     out_dims.end());
+    }
+    auto out = EigenTensor<T, (D - R_D)>::From(
+        *output, keep_dim ? DDim(out_dims) : output->dims());
     functor(&x, &out, reduce_dim);
   }
 }

lite/operators/reduce_ops.cc

@@ -50,20 +50,18 @@ bool ReduceOp::InferShape() const {
   } else {
     size_t out_rank = keep_dim ? x_rank : x_rank - dims.size();
     std::vector<DDim::value_type> out_dims(out_rank);
-    if (keep_dim) {
-      for (size_t i = 0; i < dims.size(); ++i) {
-        out_dims[dims[i]] = 1;
-      }
-    } else {
-      sort(dims.begin(), dims.end());
-      int dim_index = 0;
-      int out_index = 0;
-      for (size_t i = 0; i < x_rank; ++i) {
-        if (dims[dim_index] == static_cast<DDim::value_type>(i)) {
-          dim_index++;
-        } else {
-          out_dims[out_index++] = x_dims[i];
+    sort(dims.begin(), dims.end());
+    int dim_index = 0;
+    int out_index = 0;
+    for (size_t i = 0; i < x_rank; ++i) {
+      if (dim_index < dims.size() &&
+          dims[dim_index] == static_cast<DDim::value_type>(i)) {
+        if (keep_dim) {
+          out_dims[out_index++] = 1;
         }
+        dim_index++;
+      } else {
+        out_dims[out_index++] = x_dims[i];
       }
     }
     param_.output->Resize(out_dims);