Function veho::matrix::indexed_mutate

pub fn indexed_mutate<'a, R, M, F>(mx: M, f: F) where
    R: IntoIterator + 'a,
    M: IntoIterator<Item = &'a mut R, IntoIter = IterMut<'a, R>>,
    M::Item: IntoIterator<Item = &'a mut R::Item, IntoIter = IterMut<'a, R::Item>>,
    F: FnMut(usize, usize, &mut R::Item),