} else if (middle_diff > 0) {
XBT_CDEBUG(surf_lagrange_dichotomy, "Decreasing max");
max = middle;
overall_error = max_diff - middle_diff;
max_diff = middle_diff;
} else if (middle_diff > 0) {
XBT_CDEBUG(surf_lagrange_dichotomy, "Decreasing max");
max = middle;
overall_error = max_diff - middle_diff;
max_diff = middle_diff;