 sample calling program.
        </li>
        <li>
          <a href = "lagrange_approx_1d_test02.m">lagrange_approx_1d_test02.m</a>,
          using evenly spaced control points.
        </li>
        <li>
          <a href = "lagrange_approx_1d_test03.m">lagrange_approx_1d_test03.m</a>,
          using Chebyshev spaced control points.
        </li>
        <li>
          <a href = "lagrange_approx_1d_test_output.txt">lagrange_approx_1d_test_output.txt</a>,
          the output file.
        </li>
      <