in ndarray Copy function:

        mshadow::Copy(to->FlatTo1D<cpu, DType>(),
                      from.FlatTo1D<cpu, DType>());

FlatTo1D will cause a int of Shape overflow problem. Because the Shape value type is index_t which range is on int. Sometimes, we need to handle a very big data, which size will exceed the range of int.
So... I suggest the following code:

        mshadow::Copy(to->FlatTo2D<cpu, DType>(),
                      from.FlatTo2D<cpu, DType>());

yes....just convert to 2D shape, we will be able to handle much bigger very big array data.

how about it?
@piiswrong