def _init_matrix(self, data, index, columns, dtype=None):
data = prep_ndarray(data, copy=False)<EOL>index, columns = self._prep_index(data, index, columns)<EOL>data = {idx: data[:, i] for i, idx in enumerate(columns)}<EOL>return self._init_dict(data, index, columns, dtype)<EOL>
Init self from ndarray or list of lists.