def test_success():
f.calls = 0
result = rootfinding.bracket_root(f, (0, -0.1))
check_result(result, f, f_calls=f.calls, has_bracket=True, has_root=False)
assert result.iterations >= 1
rootfinding.bisect(f, result.bracket, f_bracket=result.f_bracket)
def test_growth_factor2():
growth_factor = 3.14
interval = (0, -0.1)
f.calls = 0
result = rootfinding.bracket_root(f, interval, growth_factor=growth_factor)
check_result(result, f, f_calls=f.calls, has_bracket=True, has_root=False)
assert result.bracket[1] - result.bracket[0] == pytest.approx(
(interval[1] - interval[0]) * growth_factor**result.iterations)
def test_iterationlimit():
f.calls = 0
with pytest.raises(rootfinding.IterationLimitReached) as exc_info:
result = rootfinding.bracket_root(f, (-1, -2))
exc = exc_info.value
check_iterationlimitreached(exc, f, f_calls=f.calls)
with pytest.raises(rootfinding.NotABracketError):
rootfinding.bisect(f, exc.interval, f_bracket=exc.f_interval)
def test_instantbracket():
interval = (0, 2)
f_interval = (None, f(interval[1]))
f.calls = 0
result = rootfinding.bracket_root(f,
interval,
f_interval=f_interval,
maxiter=0)
assert f.calls == 1
check_result(result, f, f_calls=f.calls, has_bracket=True, has_root=False)
rootfinding.bisect(f, result.bracket, f_bracket=result.f_bracket)
def test_instantroot2():
interval = (-1, 0)
f_interval = (f(interval[0]), None)
ftol = 0
f.calls = 0
result = rootfinding.bracket_root(f,
interval,
f_interval=f_interval,
ftol=ftol,
maxiter=0)
assert f.calls == 1
check_result(result,
f,
ftol=ftol,
f_calls=f.calls,
has_bracket=False,
has_root=True)
def test_instantrootwithbracket():
interval = (0, -1.00001)
f_interval = (f(interval[0]), None)
ftol = 1e-3
f.calls = 0
result = rootfinding.bracket_root(f,
interval,
f_interval=f_interval,
ftol=ftol,
maxiter=0)
assert f.calls == 1
check_result(result,
f,
ftol=ftol,
f_calls=f.calls,
has_bracket=True,
has_root=True)
rootfinding.bisect(f, result.bracket)
def test_invalidmaxiter():
with pytest.raises(ValueError):
rootfinding.bracket_root(f, (0, -0.1), maxiter=-0.5)
def test_invalidftol():
with pytest.raises(ValueError):
rootfinding.bracket_root(f, (0, -0.1), ftol=-1e-3)
def test_invalidgrowth_factor():
with pytest.raises(ValueError):
rootfinding.bracket_root(f, (0, -0.1), growth_factor=0.5)
def test_invalidinterval():
with pytest.raises(ValueError):
rootfinding.bracket_root(f, (0, 0))
