Animations for the introduction of the prime spiral video

This commit is contained in:
Grant Sanderson
2019-09-19 13:39:02 -07:00
parent 42e0cd07ac
commit 2bb8afa9e0

View File

@ -1,7 +1,10 @@
from manimlib.imports import *
import json
OUTPUT_DIRECTORY = "spirals"
INV_113_MOD_710 = 377 # Inverse of 113 mode 710
INV_7_MOD_44 = 19
def generate_prime_list(*args):
@ -25,58 +28,133 @@ def generate_prime_list(*args):
return result
class SpiralScene(Scene):
def get_gcd(x, y):
while y > 0:
x, y = y, x % y
return x
def read_in_primes(max_N=None):
with open(os.path.join("assets", "primes.json")) as fp:
primes = np.array(json.load(fp))
if max_N:
return primes[primes <= max_N]
return primes
class SpiralScene(MovingCameraScene):
CONFIG = {
"axes_config": {
"number_line_config": {
"stroke_width": 1.5,
}
}
},
"default_dot_color": TEAL,
"p_spiral_width": 6,
}
def setup(self):
super().setup()
self.axes = Axes(**self.axes_config)
self.add(self.axes)
def get_dots_in_spiral(self, sequence, axes=None, dot_radius=None):
def get_v_spiral(self, sequence, axes=None, data_point_width=None):
if axes is None:
axes = self.axes
if dot_radius is None:
if data_point_width is None:
unit = get_norm(axes.c2p(1, 0) - axes.c2p(0, 0)),
dot_radius = max(
0.1 / (-np.log10(unit) + 1),
0.01,
data_point_width = max(
0.2 / (-np.log10(unit) + 1),
0.02,
)
return VGroup(*[
Dot(
self.get_polar_point(n, n, axes),
radius=dot_radius,
fill_color=TEAL,
)
Square(
side_length=data_point_width,
fill_color=self.default_dot_color,
fill_opacity=1,
stroke_width=0,
).move_to(self.get_polar_point(n, n, axes))
for n in sequence
])
def get_polar_point(self, r, theta, axes):
def get_p_spiral(self, sequence, axes=None):
if axes is None:
axes = self.axes
result = PMobject(
color=self.default_dot_color,
stroke_width=self.p_spiral_width,
)
result.add_points([
self.get_polar_point(n, n, axes)
for n in sequence
])
return result
def get_prime_v_spiral(self, max_N, **kwargs):
primes = read_in_primes(max_N)
return self.get_v_spiral(primes, **kwargs)
def get_prime_p_spiral(self, max_N, **kwargs):
primes = read_in_primes(max_N)
return self.get_p_spiral(primes, **kwargs)
def get_polar_point(self, r, theta, axes=None):
if axes is None:
axes = self.axes
return axes.c2p(r * np.cos(theta), r * np.sin(theta))
def set_scale(self, scale, exceptions=None, run_time=3):
axes = self.axes
if exceptions is None:
exceptions = []
def set_scale(self, scale,
axes=None,
spiral=None,
to_shrink=None,
min_data_point_width=0.05,
target_p_spiral_width=None,
run_time=3):
if axes is None:
axes = self.axes
sf = self.get_scale_factor(scale, axes)
unit = get_norm(axes.c2p(1, 0) - axes.c2p(0, 0))
sf = unit / scale
anims = []
for mob in [axes, spiral, to_shrink]:
if mob is None:
continue
mob.generate_target()
mob.target.scale(sf, about_point=ORIGIN)
if mob is spiral:
if isinstance(mob, VMobject):
old_width = mob[0].get_width()
for submob in mob.target:
submob.set_width(max(
old_width * sf,
min_data_point_width,
))
elif isinstance(mob, PMobject):
if target_p_spiral_width is not None:
mob.target.set_stroke_width(target_p_spiral_width)
anims.append(MoveToTarget(mob))
self.remove(*exceptions)
self.play(*[
ApplyMethod(
mob.scale, sf,
about_point=ORIGIN,
if run_time == 0:
for anim in anims:
anim.begin()
anim.update(1)
anim.finish()
else:
self.play(
*anims,
run_time=run_time,
rate_func=lambda t: interpolate(
smooth(t),
smooth(t)**(sf**(0.5)),
t,
)
)
for mob in self.get_top_level_mobjects()
])
def get_scale_factor(self, target_scale, axes=None):
if axes is None:
axes = self.axes
unit = get_norm(axes.c2p(1, 0) - axes.c2p(0, 0))
return 1 / (target_scale * unit)
# Scenes
@ -101,7 +179,9 @@ class RefresherOnPolarCoordinates(MovingCameraScene):
plane = NumberPlane()
plane.add_coordinates()
x, y = 3, 2
x = 3 * np.cos(PI / 6)
y = 3 * np.sin(PI / 6)
point = plane.c2p(x, y)
xp = plane.c2p(x, 0)
origin = plane.c2p(0, 0)
@ -114,7 +194,7 @@ class RefresherOnPolarCoordinates(MovingCameraScene):
dot = Dot(point)
coord_label = self.get_coord_label(x, y, x_color, y_color)
coord_label = self.get_coord_label(0, 0, x_color, y_color)
x_coord = coord_label.x_coord
y_coord = coord_label.y_coord
@ -251,6 +331,7 @@ class RefresherOnPolarCoordinates(MovingCameraScene):
ChangeDecimalToValue(degree_label, theta_value / DEGREES),
)
self.play(
degree_label.scale, 0.9,
degree_label.move_to, theta_coord,
FadeInFromDown(theta_label),
)
@ -371,9 +452,8 @@ class RefresherOnPolarCoordinates(MovingCameraScene):
self.wait()
# And now 3
self.play(theta_tracker.set_value, 3)
self.play(
Transform(arc, self.get_arc(3)),
theta_tracker.set_value, 3,
Rotate(r_line, angle=1, about_point=ORIGIN),
)
self.wait()
@ -382,6 +462,17 @@ class RefresherOnPolarCoordinates(MovingCameraScene):
)
self.wait()
# Finally 4
self.play(
theta_tracker.set_value, 4,
Rotate(r_line, angle=1, about_point=ORIGIN),
)
self.wait()
self.play(
r_line.scale, 4 / 3, {"about_point": ORIGIN}
)
self.wait()
# Zoom out and show spiral
spiral = ParametricFunction(
lambda t: self.get_polar_point(t, t),
@ -466,7 +557,9 @@ class RefresherOnPolarCoordinates(MovingCameraScene):
include_background_rectangle=True,
**decimal_kwargs):
x_coord = DecimalNumber(x, **decimal_kwargs)
x_coord.set_color(x_color)
y_coord = DecimalNumber(y, **decimal_kwargs)
y_coord.set_color(y_color)
coord_label = VGroup(
TexMobject("("), x_coord,
@ -496,33 +589,253 @@ class RefresherOnPolarCoordinates(MovingCameraScene):
)
class SpiralSceneTest(SpiralScene):
class IntroducePrimePatterns(SpiralScene):
CONFIG = {
"small_n_primes": 25000,
"big_n_primes": 1000000,
"axes_config": {
"x_min": -25,
"x_max": 25,
"y_min": -25,
"y_max": 25,
},
"spiral_scale": 3e3,
"ray_scale": 1e5,
}
def construct(self):
N = 1 * 10**4
axes = self.axes
self.slowly_zoom_out()
self.show_clumps_of_four()
primes = generate_prime_list(N)
prime_dots = self.get_dots_in_spiral(primes)
def slowly_zoom_out(self):
zoom_time = 8
scale_factor = TAU / N
prime_spiral = self.get_prime_p_spiral(self.small_n_primes)
prime_spiral.set_stroke_width(25)
self.add(prime_spiral)
axes.generate_target(use_deepcopy=True)
axes.target.scale(scale_factor, about_point=ORIGIN)
prime_dots.target = self.get_dots_in_spiral(primes, axes.target)
self.add(prime_dots)
self.set_scale(3, spiral=prime_spiral)
self.wait()
self.set_scale(0.1)
# self.add(ParametricFunction(
# lambda t: axes.c2p(t * np.cos(t), t * np.sin(t)),
# t_min=0,
# t_max=30,
# ))
return
ap_dots = self.get_dots_in_spiral(range(0, N, 666))
ap_dots.set_color(YELLOW)
self.play(ShowIncreasingSubsets(ap_dots))
self.set_scale(
self.spiral_scale,
spiral=prime_spiral,
target_p_spiral_width=8,
run_time=zoom_time,
)
self.wait()
self.remove(prime_spiral)
prime_spiral = self.get_prime_p_spiral(self.big_n_primes)
prime_spiral.set_stroke_width(8)
self.set_scale(
self.ray_scale,
spiral=prime_spiral,
target_p_spiral_width=4,
run_time=zoom_time,
)
self.wait()
def show_clumps_of_four(self):
line_groups = VGroup()
for n in range(71):
group = VGroup()
for k in [-3, -1, 1, 3]:
r = ((10 * n + k) * INV_113_MOD_710) % 710
group.add(self.get_arithmetic_sequence_line(
710, r, self.big_n_primes
))
line_groups.add(group)
line_groups.set_stroke(YELLOW, 2, opacity=0.5)
self.play(ShowCreation(line_groups[0]))
for g1, g2 in zip(line_groups, line_groups[1:5]):
self.play(
FadeOut(g1),
ShowCreation(g2)
)
self.play(
FadeOut(line_groups[4]),
LaggedStartMap(
VFadeInThenOut,
line_groups[4:],
lag_ratio=0.5,
run_time=5,
)
)
self.wait()
def get_arithmetic_sequence_line(self, N, r, max_val, skip_factor=5):
line = VMobject()
line.set_points_smoothly([
self.get_polar_point(x, x)
for x in range(r, max_val, skip_factor * N)
])
return line
class AskWhat(TeacherStudentsScene):
def construct(self):
screen = self.screen
self.student_says(
"I'm sory,\\\\what?!?",
target_mode="angry",
look_at_arg=screen,
student_index=2,
added_anims=[
self.teacher.change, "happy", screen,
self.students[0].change, "confused", screen,
self.students[1].change, "confused", screen,
]
)
self.wait(3)
class CountSpirals(IntroducePrimePatterns):
CONFIG = {
"count_sound": "pen_click.wav",
}
def construct(self):
prime_spiral = self.get_prime_p_spiral(self.small_n_primes)
self.add(prime_spiral)
self.set_scale(
self.spiral_scale,
spiral=prime_spiral,
run_time=0,
)
spiral_lines = self.get_all_primative_arithmetic_lines(
44, self.small_n_primes, INV_7_MOD_44,
)
spiral_lines.set_stroke(YELLOW, 2, opacity=0.5)
counts = VGroup()
for n, spiral in zip(it.count(1), spiral_lines):
count = Integer(n)
count.move_to(spiral.point_from_proportion(0.25))
counts.add(count)
run_time = 3
self.play(
ShowIncreasingSubsets(spiral_lines),
ShowSubmobjectsOneByOne(counts),
run_time=run_time,
rate_func=linear,
)
self.add_count_clicks(len(spiral_lines), run_time)
self.play(
counts[-1].scale, 3,
counts[-1].set_stroke, BLACK, 5, {"background": True},
)
self.wait()
def get_all_primative_arithmetic_lines(self, N, max_val, mult_factor):
lines = VGroup()
for r in range(1, N):
if get_gcd(N, r) == 1:
lines.add(
self.get_arithmetic_sequence_line(N, (mult_factor * r) % N, max_val)
)
return lines
def add_count_clicks(self, N, time, rate_func=linear):
alphas = np.arange(0, 1, 1 / N)
if rate_func is linear:
delays = time * alphas
else:
delays = time * np.array([
binary_search(
rate_func,
alpha,
0,
1,
)
for alpha in alphas
])
for delay in delays:
self.add_sound(
self.count_sound,
time_offset=-delay,
gain=-15,
)
class CountRays(CountSpirals):
def construct(self):
prime_spiral = self.get_prime_p_spiral(self.big_n_primes)
self.add(prime_spiral)
self.set_scale(
self.ray_scale,
spiral=prime_spiral,
run_time=0,
)
spiral_lines = self.get_all_primative_arithmetic_lines(
710, self.big_n_primes, INV_113_MOD_710,
)
spiral_lines.set_stroke(YELLOW, 2, opacity=0.5)
counts = VGroup()
for n, spiral in zip(it.count(1), spiral_lines):
count = Integer(n)
count.move_to(spiral.point_from_proportion(0.25))
counts.add(count)
run_time = 6
self.play(
ShowIncreasingSubsets(spiral_lines),
ShowSubmobjectsOneByOne(counts),
run_time=run_time,
rate_func=smooth,
)
self.add_count_clicks(len(spiral_lines), run_time, rate_func=smooth)
self.play(
counts[-1].scale, 3,
counts[-1].set_stroke, BLACK, 5, {"background": True},
)
self.wait()
self.play(FadeOut(spiral_lines))
self.wait()
class AskAboutRelationToPrimes(TeacherStudentsScene):
def construct(self):
numbers = TextMobject("20, 280")
arrow = Arrow(LEFT, RIGHT)
primes = TextMobject("2, 3, 5, 7, 11, \\dots")
q_marks = TextMobject("???")
q_marks.set_color(YELLOW)
group = VGroup(numbers, arrow, primes)
group.arrange(RIGHT)
q_marks.next_to(arrow, UP)
group.add(q_marks)
group.scale(1.5)
group.next_to(self.pi_creatures, UP, LARGE_BUFF)
self.play(
self.get_student_changes(
*3 * ["maybe"],
look_at_arg=numbers,
),
self.teacher.change, "maybe", numbers,
ShowCreation(arrow),
FadeInFrom(numbers, RIGHT)
)
self.play(
FadeInFrom(primes, LEFT),
)
self.play(
LaggedStartMap(FadeInFromDown, q_marks[0]),
Blink(self.teacher)
)
self.wait(3)
class ZoomOutOnPrimesWithNumbers(IntroducePrimePatterns):
def construct(self):
pass