Bcast sending wrong buffer

[ClaudiaComito]

Description
ht.communication.Bcast seems to send the wrong portion of a buffer when broadcasting a slice of an array that does not start at index 0.

To Reproduce

a = ht.arange(13*5, split=0).reshape((13, 5))
active_rank = 1
if a.comm.rank == active_rank:
    arr = a.larray[1:2]
else:
    arr = torch.empty((1,5), dtype=a.larray.dtype)
print("before Bcast on rank ", rank, ", arr = ", arr)
a.comm.Bcast(arr, root=active_rank)
print("after Bcast on rank ", rank, ", arr = ", arr)

mpirun -n 2

before Bcast on rank  1 , arr =  tensor([[40, 41, 42, 43, 44]], dtype=torch.int32)
before Bcast on rank  0 , arr =  tensor([[        1, 423460512,         1,         1,         0]], dtype=torch.int32)
after Bcast on rank  0 , arr =  tensor([[704643072, 721420288, 738197504, 754974720, 771751936]], dtype=torch.int32)
after Bcast on rank  1 , arr =  tensor([[40, 41, 42, 43, 44]], dtype=torch.int32)

Expected behavior

a = ht.arange(13*5, split=0).reshape((13, 5))
active_rank = 1
if a.comm.rank == active_rank:
    arr = a.larray[0:1]
else:
    arr = torch.empty((1,5), dtype=a.larray.dtype)
print("before Bcast on rank ", rank, ", arr = ", arr)
a.comm.Bcast(arr, root=active_rank)
print("after Bcast on rank ", rank, ", arr = ", arr)

mpirun -n 2

before Bcast on rank  0 , arr =  tensor([[         0, 1073741824,          0, 1073741824,  465895430]], dtype=torch.int32)
before Bcast on rank  1 , arr =  tensor([[40, 41, 42, 43, 44]], dtype=torch.int32)
after Bcast on rank  0 , arr =  tensor([[40, 41, 42, 43, 44]], dtype=torch.int32)
after Bcast on rank  1 , arr =  tensor([[40, 41, 42, 43, 44]], dtype=torch.int32)

Version Info
Main branch

[ClaudiaComito]

Might be similar or same issue as in #769

[ClaudiaComito]

This has been addressed. Closing.