Function check

numpy/core/tests/test_mem_overlap.py:398–412

(A, U, exists=None)

def test_internal_overlap_diophantine():
    def check(A, U, exists=None):
        X = solve_diophantine(A, U, 0, require_ub_nontrivial=1)

        if exists is None:
            exists = (X is not None)

        if X is not None:
            assert_(sum(a*x for a, x in zip(A, X)) == sum(a*u//2 for a, u in zip(A, U)))
            assert_(all(0 <= x <= u for x, u in zip(X, U)))
            assert_(any(x != u//2 for x, u in zip(X, U)))

        if exists:
            assert_(X is not None, repr(X))
        else:
            assert_(X is None, repr(X))

    # Smoke tests
    check((3, 2), (2*2, 3*2), exists=True)