added mean tests

test/forward.json

@@ -63,6 +63,22 @@
     "fill_value": 1,
     "expected": [[0.25, 0.25], [0.125, 0.5]]
   },
+  {
+    "name": "mean",
+    "index": [[4, 5, 4, 2, 3], [0, 0, 2, 2, 1]],
+    "input": [[2, 0, 1, 4, 3], [0, 2, 1, 3, 4]],
+    "dim": 1,
+    "fill_value": 0,
+    "expected": [[0, 0, 4, 3, 1.5, 0], [1, 4, 2, 0, 0, 0]]
+  },
+  {
+    "name": "mean",
+    "index": [[0, 0], [1, 1], [1, 1], [0, 0]],
+    "input": [[5, 2], [2, 5], [4, 3], [1, 3]],
+    "dim": 0,
+    "fill_value": 0,
+    "expected": [[3, 2.5], [3, 4]]
+  },
   {
     "name": "max",
     "index": [[4, 5, 4, 2, 3], [0, 0, 2, 2, 1]],

torch_scatter/src/generic/cpu.c

@@ -26,9 +26,10 @@ void scatter_(mean)(int dim, THTensor *output, THLongTensor *index, THTensor *in
   int64_t i, idx;
   TH_TENSOR_DIM_APPLY4(real, output, int64_t, index, real, input, real, count, dim,
     for (i = 0; i < THLongTensor_size(index, dim); i++) {
-      assertIndexInBoundaries(index_data[i], output_size, TH_TENSOR_DIM_APPLY_counter);
+      idx = *(index_data + i * index_stride);
+      assertIndexInBoundaries(idx, output_size, TH_TENSOR_DIM_APPLY_counter);
       output_data[idx * output_stride] += *(input_data + i * input_stride);
-      output_data[idx * count_stride]++;
+      count_data[idx * count_stride]++;
     })
 }