del :: (Num a, DIM n) => SparseVector n a -> Index -> SparseVector n a
del v i = SV (M.delete i (vec $ checkDim i v))
del :: (Num a, DIM n) => SparseVector n a -> Index -> SparseVector n a
del v i = SV (M.delete i (vec $ checkDim i v))
del v i = SV (M.delete i (vec $ checkDim i v))