When amt contains missing values, they need to be filled with 0 and they are in the C++ code. However, the data passed to the C++ code were still pointers to the columns in the data frame and the source data frame was getting modified (see #40).
This PR implements a clone() step so amt isn't modified in the source data frame.
Summary
When
amtcontains missing values, they need to be filled with0and they are in the C++ code. However, the data passed to the C++ code were still pointers to the columns in the data frame and the source data frame was getting modified (see #40).This PR implements a
clone()step soamtisn't modified in the source data frame.