# Algorithms

Information about optimization algorithms

- What does "Presolve: All rows and columns removed" mean?
- How can I return from multi-objective optimization back to single-objective mode?
- Why can't I get the Pi values for a MIP problem?
- Is Gurobi Optimizer deterministic?
- What is the difference between user cuts and lazy constraints?
- Why do I see increasing/large MIP gap values?
- How does presolve() work?
- How do you implement lazy constraints in Gurobi?
- Can you modify the branch-and-bound algorithm or create a branch-cut-and-price algorithm?
- Does Gurobi have a solution polishing algorithm?
- How do I find additional solutions to a model?
- Does the barrier algorithm return a basic solution for LPs?
- When will more threads make it faster to solve a model?
- Why does Gurobi sometimes return values for integer variables that are not integers?