Lipshitz - Piyavsky

void MainWin::piyavsky(){

    double L = ThinkL();

    std::vector<pv> v;


    v.push_back(pv(a, f(a)));
    v.push_back(pv(b, f(b)));


    double up = b;
    double un = u(a, b, L);

    v.push_back(pv(un, f(un)));

    int k = 3;

    while (fabs(f(un) - f(up)) >= e)
    {
        ++k;

        std::sort(v.begin(), v.end(), std::less<pv>());

        int p;

        for (int i = 0; i < static_cast<int> (v.size()); i++){
            if (un == v[i].point){
                p = i;
                break;
            }
        }

        if (un != a){
            double ul = u(v[p - 1].point, v[p].point, L);
            v.push_back(pv(ul, g(un, ul, L)));
        }
        if (un != b){
            double ur = u(v[p].point, v[p + 1].point, L);
            v.push_back(pv(ur, g(un, ur, L)));
        }

        up = un;

        double min = v[0].value;
        int min_p = 0;
        for (int i = 1; i < static_cast<int> (v.size()); i++){
            if (v[i].value < min){
                min = v[i].value;
                min_p = i;
            }
        }

        un = v[min_p].point;
        v[min_p].value = f(un);
    }

    ui->LEdit->setText(QString::number(L));
    ui->uEdit->setText(QString::number(un));
    ui->JuEdit->setText(QString::number(f(un)));
    ui->IterEdit->setText(QString::number(k));

}

void MainWin::on_runButton_clicked()
{
    fString = ui->functionEdit->text();
    a = ui->xminEdit->text().toDouble();
    b = ui->xmaxEdit->text().toDouble();
    e = ui->epsEdit->text().toDouble();

    piyavsky();
}