let leading_row = thetas
            .iter()
            .enumerate()
            .filter_map(|(i, b)| {
                if let Some(sb) = b {
                    Some((i, sb))
                } else {
                    None
                }
            })
            .min_by(|(_, x), (_, y)| x.partial_cmp(y).unwrap())
            .ok_or(SimplexError::NoSolutions)?
            .0;

        println!("lead_row\n{:.2}", &leading_row);

        // update leading row
        let lead_element = table_datas[(leading_row, leading_column + 1)];
        azip!((row_elem in &mut table_datas.index_axis_mut(Axis(0), leading_row))
            *row_elem = *row_elem / lead_element);

        let l_row = table_datas.index_axis(Axis(0), leading_row).to_owned();
        let l_col = table_datas
            .index_axis(Axis(1), leading_column + 1)
            .to_owned();

        // update everything else
        azip!((index (i, j), data in &mut table_datas)
            *data = if i != leading_row { *data - l_row[j] * l_col[i] } else { *data });