def test_normal_vector(self, a: Point):
if isclose(abs(a), 0.0):
with pytest.raises(ZeroDivisionError):
a.normal()
else:
angle = a.normal().angle() - a.angle()
assert isclose(angle, np.pi / 2.0)
def test_rotation_about_zero(self, a: Point, angle: Angle):
assume(abs(a) != 0)
b = a.rotate(angle, Point(0.0, 0.0))
aa = a.angle()
bb = b.angle()
note(f"a angle: {aa}")
note(f"b angle: {bb}")
assert isclose(bb - aa, angle)
def __init__(
self,
start: Point,
length: float,
width: float = None,
bar_length: float = None,
num_windings: int = 11,
teeth: bool = False,
):
B = start
n = num_windings - 1 # n counts teeth intervals
if n <= 6:
n = 7
# n must be odd:
if n % 2 == 0:
n = n + 1
L = length
if width is None:
w = L / 10.0
else:
w = width / 2.0
s = bar_length
shapes = {}
if s is None:
f = Spring.spring_fraction
s = L * (1 - f) / 2.0 # start of spring
self.bar_length = s # record
self.width = 2 * w
p0 = Point(B.x, B.y + s)
p1 = Point(B.x, B.y + L - s)
p2 = Point(B.x, B.y + L)
if s >= L:
raise ValueError(
"length of first bar: %g is larger than total length: %g" %
(s, L))
shapes["bar1"] = Line(B, p0)
spring_length = L - 2 * s
t = spring_length / n # height increment per winding
if teeth:
resolution = 4
else:
resolution = 90
q = np.linspace(0, n, n * resolution + 1)
xs = p0.x + w * np.sin(2 * np.pi * q)
ys = p0.y + q * t
points = Point.from_coordinate_lists(xs, ys)
shapes["spiral"] = Curve(points)
shapes["bar2"] = Line(p1, p2)
super().__init__(shapes)
def test_angle(self, a: Point):
if a.x != 0.0:
assume(abs(a.y / a.x) < 1e4)
if a.y != 0.0:
assume(abs(a.x / a.y) < 1e4)
angle = a.angle()
note(angle)
b = Point(abs(a), 0.0).rotate(angle, Point(0.0, 0.0))
note(f"The angle is : {np.format_float_scientific(a.angle())}")
note(f"The length is : {np.format_float_scientific(abs(a))}")
assert b == a
assert -np.pi <= angle <= np.pi
def composition(self):
shape1 = Line(Point(0, 1), Point(1, 1))
shape2 = Line(Point(1, 1), Point(0, 2))
text = Text("This is a test.", Point(2, 2))
composition = Composition(
{
"shape1": shape1,
"shape2": shape2,
"test": text,
}
)
return composition
def main():
circle = Circle(Point(0, 0), 1)
line = Line(Point(0, 0), Point(0, 1))
def func(frame: int):
new_line = line.rotate(Angle(2 * np.pi * frame / 360), Point(0, 0))
model = Composition({"circle": circle, "line": new_line})
return model
fig = Figure(-1.2, 1.2, -1.2, 1.2, backend=MatplotlibBackend)
fig.animate(func, (0, 360))
fig.save_animation("animation.mp4")
def test_rotation(self, a: Point, angle: Angle, center: Point):
assume(abs(a - center) != 0)
b = a.rotate(angle, center)
new_angle = (b - center).angle() - (a - center).angle()
note(angle)
note(new_angle)
assert isclose(angle, angle)
def main() -> None:
logging.basicConfig(level=logging.INFO)
L = 8.0
H = 1.0
x_pos = 2.0
y_pos = 3.0
fig = Figure(0, x_pos + 1.2 * L, 0, y_pos + 5 * H, MatplotlibBackend)
p0 = Point(x_pos, y_pos)
main = Rectangle(p0, L,
H).set_fill_pattern(Style.FillPattern.UP_LEFT_TO_RIGHT)
h = L / 16 # size of support, clamped wall etc
support = SimpleSupport(p0, h)
clamped = Rectangle(p0 + Point(L, 0) - Point(0, 2 * h), h, 6 *
h).set_fill_pattern(Style.FillPattern.UP_RIGHT_TO_LEFT)
F_pt = Point(p0.x + L / 2, p0.y + H)
force = Force("$F$", F_pt + Point(0, 2 * H), F_pt).set_line_width(3)
L_dim = LinearDimension("$L$", Point(x_pos, p0.y - 3 * h),
Point(x_pos + L, p0.y - 3 * h))
beam = Composition({
"main": main,
"simply supported end": support,
"clamped end": clamped,
"force": force,
"L": L_dim,
})
fig.add(beam)
fig.show()
def test_unit_vector(self, x: float, y: float):
a = Point(x, y)
if isclose(abs(a), 0.0):
with pytest.raises(ZeroDivisionError):
a.unit_vector
else:
b = a.unit_vector
note(f"angle of a: {np.format_float_scientific(a.angle)}")
note(f"angle of b: {np.format_float_scientific(b.angle)}")
assert isclose(a.angle, b.angle)
note(f"magnitude of b: {abs(b)}")
assert isclose(abs(b), 1.0)
def inclined_plane():
theta = np.pi / 6
L = 10.0
a = 1.0
x_min = 0.0
y_min = -3.0
B = Point(a + L, 0)
A = Point(a, np.tan(theta) * L)
wall = Wall([A, B], thickness=-0.25)
wall.style.fill_pattern = Style.FillPattern.UP_LEFT_TO_RIGHT
angle = ArcWithText(
r"$\theta$", center=B, radius=3, start_angle=np.pi - theta, arc_angle=theta
)
angle.style.line_color = Style.Color.BLACK
angle.style.line_width = 1
ground = Line(Point(B.x - L / 10.0, 0), Point(B.x - L / 2.0, 0))
ground.style.line_color = Style.Color.BLACK
ground.style.line_style = Style.LineStyle.DASHED
ground.style.line_width = 1
r = 1.0 # radius of wheel
help_line = Line(A, B)
x = a + 3 * L / 10.0
y = help_line(x=x)
contact = Point(x, y)
normal_vec = Point(np.sin(theta), np.cos(theta))
c = contact + normal_vec * r
outer_wheel = (
Circle(c, r).set_line_color(Style.Color.BLUE).set_fill_color(Style.Color.BLUE)
)
hole = (
Circle(c, r / 2.0)
.set_line_color(Style.Color.BLUE)
.set_fill_color(Style.Color.WHITE)
)
wheel = Composition({"outer": outer_wheel, "inner": hole})
N = Force("$N$", contact - normal_vec * 2 * r, contact, spacing=0.2)
N.style.line_color = Style.Color.BLACK
# text_alignment='left')
mg = Gravity(c, 3 * r, text="$Mg$", text_position=Gravity.TextPosition.END)
x_const = Line(contact, contact + Point(0, 4))
x_const.style.line_style = Style.LineStyle.DOTTED
x_const = x_const.rotate(-theta, contact)
x_axis = Axis(
start=contact + normal_vec * 3.0 * r,
length=4 * r,
label="$x$",
rotation_angle=-theta,
)
body = Composition({"wheel": wheel, "N": N, "mg": mg})
fixed = Composition(
{
"angle": angle,
"inclined wall": wall,
"wheel": wheel,
"ground": ground,
"x start": x_const,
"x axis": x_axis,
}
)
model = Composition({"fixed elements": fixed, "body": body})
fig = Figure(x_min, x_min + 1.5 * L, y_min, y_min + L, backend=MatplotlibBackend)
fig.add(model)
fig.show()
time.sleep(1)
tangent_vec = Point(normal_vec.y, -normal_vec.x)
def position(t):
"""Position of center point of wheel."""
return c + tangent_vec * 7 * t ** 2
def move(fig: Shape, t: float, dt: float = None) -> fig:
x = position(t)
x0 = position(t - dt)
displacement = x - x0
return fig["body"].translate(displacement)
def test_coordinates(self, x: float, y: float) -> None:
p = Point(x, y)
assert p.x == x
assert p.y == y
def composition(self):
shape1 = Line(Point(0, 1), Point(1, 1))
shape2 = Line(Point(1, 1), Point(0, 2))
composition = Composition({"shape1": shape1, "shape2": shape2})
return composition
def func(frame: int):
new_line = line.rotate(Angle(2 * np.pi * frame / 360), Point(0, 0))
model = Composition({"circle": circle, "line": new_line})
return model
def test_equality(self, x: float, y: float) -> None:
assert Point(x, y) == Point(x, y)
def test_adding(self, x1: float, x2: float, y1: float, y2: float):
a = Point(x1, y1)
b = Point(x2, y2)
assert a + b == Point(x1 + x2, y1 + y2)
def test_abs(self, x: float, y: float):
assume(x * x != inf)
assume(y * y != inf)
a = Point(x, y)
assert abs(a) == np.hypot(x, y)
def test_scale(self, x: float, y: float, s: float):
a = Point(x, y)
assert a.scale(s) == Point(x * s, y * s)
def test_multiplication(self, x: float, y: float, s: float):
a = Point(x, y)
assert a * s == Point(x * s, y * s)
def test_subtraction(self, x1: float, x2: float, y1: float, y2: float):
a = Point(x1, y1)
b = Point(x2, y2)
assert a - b == Point(x1 - x2, y1 - y2)
def test_translation(self, x1: float, x2: float, y1: float, y2: float):
a = Point(x1, y1)
b = Point(x2, y2)
assert a + b == Point(x1 + x2, y1 + y2)
