Hi, I have would like to implement such a requirement: a is a tensor(3,4), b is a tensor(5,4),  mask is a tensor = [1, 0, 1, 0, 1]. How to put a to b according to the mask where is 1? That is b[0] = a[0], b[2] = a[1], b[3] = a[2]. Thank you very much!