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assumptions_sample_sat

<table align="left"> <td> <a href="https://colab.research.google.com/github/google/or-tools/blob/main/examples/notebook/sat/assumptions_sample_sat.ipynb">Run in Google Colab</a> </td> <td> <a href="https://github.com/google/or-tools/blob/main/ortools/sat/samples/assumptions_sample_sat.py">View source on GitHub</a> </td> </table>

First, you must install ortools package in this colab.

python

%pip install ortools

Code sample that solves a model and gets the infeasibility assumptions.

python

from ortools.sat.python import cp_model



def main() -> None:
    """Showcases assumptions."""
    # Creates the model.
    model = cp_model.CpModel()

    # Creates the variables.
    x = model.new_int_var(0, 10, "x")
    y = model.new_int_var(0, 10, "y")
    z = model.new_int_var(0, 10, "z")
    a = model.new_bool_var("a")
    b = model.new_bool_var("b")
    c = model.new_bool_var("c")

    # Creates the constraints.
    model.add(x > y).only_enforce_if(a)
    model.add(y > z).only_enforce_if(b)
    model.add(z > x).only_enforce_if(c)

    # Add assumptions
    model.add_assumptions([a, b, c])

    # Creates a solver and solves.
    solver = cp_model.CpSolver()
    status = solver.solve(model)

    # Print solution.
    print(f"Status = {solver.status_name(status)}")
    if status == cp_model.INFEASIBLE:
        print(
            "sufficient_assumptions_for_infeasibility = "
            f"{solver.sufficient_assumptions_for_infeasibility()}"
        )


main()