searching for bug

test/test_max.py

@@ -6,7 +6,8 @@ from torch_scatter import scatter_max_, scatter_max
 from .utils import tensor_strs, Tensor
 
 
-@pytest.mark.parametrize('str', tensor_strs)
+# @pytest.mark.parametrize('str', tensor_strs)
+@pytest.mark.parametrize('str', ['DoubleTensor'])
 def test_scatter_mean(str):
     input = [[2, 0, 1, 4, 3], [0, 2, 1, 3, 4]]
     index = [[4, 5, 4, 2, 3], [0, 0, 2, 2, 1]]

torch_scatter/src/generic/cpu.c

@@ -65,10 +65,14 @@ void scatter_(min)(int dim, THTensor *output, THLongTensor *index, THTensor *inp
     })
 }
 
-void index_backward(int dim, THTensor  *output, THLongTensor *index, THTensor  *grad, THLongTensor *grad_index) {
+void index_backward(int dim, THTensor *output, THLongTensor *index, THTensor *grad, THLongTensor *grad_index) {
   TH_TENSOR_DIM_APPLY4(real, output, int64_t, index, real, grad, int64_t, grad_index, dim,
     for (int64_t i = 0; i < THLongTensor_size(index, dim); i++) {
-      if (grad_index_data[index_data[i]] == i) output_data[index_data[i]] = grad_data[i];
+      int64_t idx = *(index_data + i * index_stride);
+      /* if (grad_index_data[index_data[i]] == i) { */
+      /*   printf("i: %i, ", i); */
+      /* output_data[i] = grad_data[idx]; */
+      /* } */
     })
 }