Check lp feasibility as fast as possible

[psarka]

Hello, I have a somewhat non standard need for a linear solver - I don't need a solution, but I need to know if the problem is feasible as fast as possible. My problems are not very large (~20-50 variables), and should be quite "easy". This is the approach I'm using now, and I would like to know if that is correct, and maybe you have some further tips to make it even faster:

ClpSimplex  model;
model.setLogLevel(0);
int k = 28;

// Variables
model.resize(0, k);

// Objective
// No objective!

// Upper bounds
for (int i = 0; i < k; i++) {
    model.setColumnLower(i, -100.0);
    model.setColumnUpper(i, +100.0);
}

// Constraints
CoinBuild buildObject;
double plus_one_minus_one[] = {+1.0, -1.0};
double plus_one_one_minus_one_one[] = {+1.0, +1.0, -1.0, -1.0};

{int columns[] = {1, 3, 0, 2};      buildObject.addRow(4, columns, plus_one_one_minus_one_one, 6, 8);}
{int columns[] = {5, 7, 4, 6};      buildObject.addRow(4, columns, plus_one_one_minus_one_one, 3, 3);}
//...
// a bunch more.
//...
{int columns[] = {15, 22};   buildObject.addRow(2, columns, plus_one_minus_one, 0, 0);}
{int columns[] = {13, 8};    buildObject.addRow(2, columns, plus_one_minus_one, 1.0, COIN_DBL_MAX);}

 // Solve
model.addRows(buildObject);
ClpPresolve presolve_info;
ClpSimplex* presolved_model = presolve_info.presolvedModel(model);

if (presolved_model) {
    return 1;
} else {
    return 0;
}

This is the full script that I used to time this, and I'm getting ~10K solutions per second, which is quite nice! It would be good to know that it is safe to use presolve without objective for this purpose.