def col_op(self, j, f):
        self._mat[j::self.cols] = [f(*t) for t in list(zip(self._mat[j::self.cols], list(range(self.rows))))]
In-place operation on col j using two-arg functor whose args are
dataset/ETHPy150Open sympy/sympy/sympy/matrices/dense.py/MutableDenseMatrix.col_op