3b1b-manim/from_3b1b/active/bayes/beta.py

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from manimlib.imports import *
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from from_3b1b.active.bayes.beta_helpers import *
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import scipy.stats
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OUTPUT_DIRECTORY = "bayes/beta"
# Scenes
class BarChartTest(Scene):
def construct(self):
bar_chart = BarChart()
bar_chart.to_edge(DOWN)
self.add(bar_chart)
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class Thumbnail(Scene):
def construct(self):
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p1 = "$96\\%$"
p2 = "$93\\%$"
n1 = "50"
n2 = "200"
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t2c = {
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p1: BLUE,
p2: YELLOW,
n1: BLUE_C,
n2: YELLOW,
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}
kw = {"tex_to_color_map": t2c}
text = VGroup(
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TextMobject(f"{p1} with {n1} reviews", **kw),
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TextMobject("vs.", **kw),
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TextMobject(f"{p2} with {n2} reviews", **kw),
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)
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fix_percent(text[0].get_part_by_tex(p1)[-1])
fix_percent(text[2].get_part_by_tex(p2)[-1])
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text.scale(2)
text.arrange(DOWN, buff=LARGE_BUFF)
text.set_width(FRAME_WIDTH - 1)
self.add(text)
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class ShowThreeCases(Scene):
def construct(self):
titles = self.get_titles()
reviews = self.get_reviews(titles)
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for review in reviews:
review.match_x(reviews[2])
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# Introduce everything
self.play(LaggedStartMap(
FadeInFrom, titles,
lambda m: (m, DOWN),
lag_ratio=0.2
))
self.play(LaggedStart(*[
LaggedStartMap(
FadeInFromLarge, review,
lag_ratio=0.1
)
for review in reviews
], lag_ratio=0.1))
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self.add(reviews)
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self.wait()
self.play(ShowCreationThenFadeAround(reviews[2]))
self.wait()
# Suspicious of 100%
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randy = Randolph()
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randy.flip()
randy.set_height(2)
randy.next_to(
reviews[0], RIGHT, LARGE_BUFF,
aligned_edge=UP,
)
randy.look_at(reviews[0])
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self.play(FadeIn(randy))
self.play(randy.change, "sassy")
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self.play(Blink(randy))
self.wait()
self.play(FadeOut(randy))
# Low number means it could be a fluke.
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review = reviews[0]
review.generate_target()
review.target.scale(2)
review.target.arrange(RIGHT)
review.target.move_to(review)
self.play(MoveToTarget(review))
alt_negs = [1, 2, 1, 0]
alt_reviews = VGroup()
for k in alt_negs:
alt_reviews.add(self.get_plusses_and_minuses(titles[0], 1, 10, k))
for ar in alt_reviews:
for m1, m2 in zip(ar, review):
m1.replace(m2)
alt_percents = VGroup(*[
TexMobject(str(10 * (10 - k)) + "\\%")
for k in alt_negs
])
hundo = titles[0][0]
for ap in alt_percents:
fix_percent(ap.family_members_with_points()[-1])
ap.match_style(hundo)
ap.match_height(hundo)
ap.move_to(hundo, RIGHT)
last_review = review
last_percent = hundo
for ar, ap in zip(alt_reviews, alt_percents):
self.play(
FadeInFrom(ar, 0.5 * DOWN, lag_ratio=0.2),
FadeOut(last_review),
FadeInFrom(ap, 0.5 * DOWN),
FadeOutAndShift(last_percent, 0.5 * UP),
run_time=1.5
)
last_review = ar
last_percent = ap
self.remove(last_review, last_percent)
self.add(titles, *reviews)
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# How do you think about the tradeoff?
p1 = titles[1][0]
p2 = titles[2][0]
nums = VGroup(p1, p2)
lower_reviews = reviews[1:]
lower_reviews.generate_target()
lower_reviews.target.arrange(LEFT, buff=1.5)
lower_reviews.target.center()
nums.generate_target()
for nt, review in zip(nums.target, lower_reviews.target):
nt.next_to(review, UP, MED_LARGE_BUFF)
nums.target[0].match_y(nums.target[1])
self.clear()
self.play(
MoveToTarget(lower_reviews),
MoveToTarget(nums),
FadeOut(titles[1][1:]),
FadeOut(titles[2][1:]),
FadeOut(titles[0]),
FadeOut(reviews[0]),
run_time=2,
)
greater_than = TexMobject(">")
greater_than.scale(2)
greater_than.move_to(midpoint(
reviews[2].get_right(),
reviews[1].get_left(),
))
less_than = greater_than.copy().flip()
less_than.match_height(nums[0][0])
less_than.match_y(nums, DOWN)
nums.generate_target()
nums.target[1].next_to(less_than, LEFT, MED_LARGE_BUFF)
nums.target[0].next_to(less_than, RIGHT, MED_LARGE_BUFF)
squares = VGroup(*[
SurroundingRectangle(
submob, buff=0.01,
stroke_color=LIGHT_GREY,
stroke_width=1,
)
for submob in reviews[2]
])
squares.shuffle()
self.play(
LaggedStartMap(
ShowCreationThenFadeOut, squares,
lag_ratio=0.5 / len(squares),
run_time=3,
),
Write(greater_than),
)
self.wait()
self.play(
MoveToTarget(nums),
TransformFromCopy(
greater_than, less_than,
)
)
self.wait()
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def get_titles(self):
titles = VGroup(
TextMobject(
"$100\\%$ \\\\",
"10 reviews"
),
TextMobject(
"$96\\%$ \\\\",
"50 reviews"
),
TextMobject(
"$93\\%$ \\\\",
"200 reviews"
),
)
colors = [PINK, BLUE, YELLOW]
for title, color in zip(titles, colors):
fix_percent(title[0][-1])
title[0].set_color(color)
titles.scale(1.25)
titles.arrange(DOWN, buff=1.5)
titles.to_corner(UL)
return titles
def get_reviews(self, titles):
return VGroup(
self.get_plusses_and_minuses(
titles[0], 5, 2, 0,
),
self.get_plusses_and_minuses(
titles[1], 5, 10, 2,
),
self.get_plusses_and_minuses(
titles[2], 8, 25, 14,
),
)
def get_plusses_and_minuses(self, title, n_rows, n_cols, n_minus):
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check = TexMobject(CMARK_TEX, color=GREEN)
cross = TexMobject(XMARK_TEX, color=RED)
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checks = VGroup(*[
check.copy() for x in range(n_rows * n_cols)
])
checks.arrange_in_grid(n_rows=n_rows, n_cols=n_cols)
checks.scale(0.5)
# if checks.get_height() > title.get_height():
# checks.match_height(title)
checks.next_to(title, RIGHT, LARGE_BUFF)
for check in random.sample(list(checks), n_minus):
mob = cross.copy()
mob.replace(check, dim_to_match=0)
check.become(mob)
return checks
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class WhatsTheModel(Scene):
def construct(self):
self.add_questions()
self.introduce_buyer_and_seller()
for x in range(3):
self.play(*self.experience_animations(self.seller, self.buyer))
self.wait()
self.add_probability_label()
self.bring_up_goal()
def add_questions(self):
questions = VGroup(
TextMobject("What's the model?"),
TextMobject("What are you optimizing?"),
)
for question, vect in zip(questions, [LEFT, RIGHT]):
question.move_to(vect * FRAME_WIDTH / 4)
questions.arrange(DOWN, buff=LARGE_BUFF)
questions.scale(1.5)
# Intro questions
self.play(FadeInFrom(questions[0]))
self.play(FadeInFrom(questions[1], UP))
self.wait()
questions[1].save_state()
self.questions = questions
def introduce_buyer_and_seller(self):
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if hasattr(self, "questions"):
questions = self.questions
added_anims = [
questions[0].to_edge, UP,
questions[1].set_opacity, 0.5,
questions[1].scale, 0.25,
questions[1].to_corner, UR,
]
else:
added_anims = []
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seller = Randolph(mode="coin_flip_1")
seller.to_edge(LEFT)
seller.label = TextMobject("Seller")
buyer = Mortimer()
buyer.to_edge(RIGHT)
buyer.label = TextMobject("Buyer")
VGroup(buyer, seller).shift(DOWN)
labels = VGroup()
for pi in seller, buyer:
pi.set_height(2)
pi.label.scale(1.5)
pi.label.next_to(pi, DOWN, MED_LARGE_BUFF)
labels.add(pi.label)
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buyer.make_eye_contact(seller)
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self.play(
LaggedStartMap(
FadeInFromDown, VGroup(seller, buyer, *labels),
lag_ratio=0.2
),
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*added_anims
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)
self.wait()
self.buyer = buyer
self.seller = seller
def add_probability_label(self):
seller = self.seller
buyer = self.buyer
label = get_prob_positive_experience_label()
label.add(TexMobject("=").next_to(label, RIGHT))
rhs = DecimalNumber(0.75)
rhs.next_to(label, RIGHT)
rhs.align_to(label[0], DOWN)
label.add(rhs)
label.scale(1.5)
label.next_to(seller, UP, MED_LARGE_BUFF, aligned_edge=LEFT)
rhs.set_color(YELLOW)
brace = Brace(rhs, UP)
success_rate = brace.get_text("Success rate")[0]
s_sym = brace.get_tex("s").scale(1.5, about_edge=DOWN)
success_rate.match_color(rhs)
s_sym.match_color(rhs)
self.add(label)
self.play(
GrowFromCenter(brace),
FadeInFrom(success_rate, 0.5 * DOWN)
)
self.wait()
self.play(
TransformFromCopy(success_rate[0], s_sym),
FadeOutAndShift(success_rate, 0.1 * RIGHT, lag_ratio=0.1),
)
for x in range(2):
self.play(*self.experience_animations(seller, buyer, arc=30 * DEGREES))
self.wait()
grey_box = SurroundingRectangle(rhs, buff=SMALL_BUFF)
grey_box.set_stroke(GREY_E, 0.5)
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grey_box.set_fill(GREY_D, 1)
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lil_q_marks = TexMobject("???")
lil_q_marks.scale(0.5)
lil_q_marks.next_to(buyer, UP)
self.play(
FadeOutAndShift(rhs, 0.5 * DOWN),
FadeInFrom(grey_box, 0.5 * UP),
FadeInFrom(lil_q_marks, DOWN),
buyer.change, "confused", grey_box,
)
rhs.set_opacity(0)
for x in range(2):
self.play(*self.experience_animations(seller, buyer, arc=30 * DEGREES))
self.play(buyer.change, "confused", lil_q_marks)
self.play(Blink(buyer))
self.prob_group = VGroup(
label, grey_box, brace, s_sym,
)
self.buyer_q_marks = lil_q_marks
def bring_up_goal(self):
prob_group = self.prob_group
questions = self.questions
questions.generate_target()
questions.target[1].replace(questions[0], dim_to_match=1)
questions.target[1].match_style(questions[0])
questions.target[0].replace(questions[1], dim_to_match=1)
questions.target[0].match_style(questions[1])
prob_group.generate_target()
prob_group.target.scale(0.5)
prob_group.target.next_to(self.seller, RIGHT)
self.play(
FadeOut(self.buyer_q_marks),
self.buyer.change, "pondering", questions[0],
self.seller.change, "pondering", questions[0],
MoveToTarget(prob_group),
MoveToTarget(questions),
)
self.play(self.seller.change, "coin_flip_1")
for x in range(3):
self.play(*self.experience_animations(self.seller, self.buyer))
self.wait()
#
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def experience_animations(self, seller, buyer, arc=-30 * DEGREES, p=0.75):
positive = (random.random() < p)
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words = TextMobject(
"Positive\\\\experience"
if positive else
"Negative\\\\experience"
)
words.set_color(GREEN if positive else RED)
if positive:
new_mode = random.choice([
"hooray",
"happy",
])
else:
new_mode = random.choice([
"tired",
"angry",
"sad",
])
words.move_to(seller.get_corner(UR))
result = [
ApplyMethod(
words.move_to, buyer.get_corner(UL),
path_arc=arc,
run_time=2
),
VFadeInThenOut(words, run_time=2),
ApplyMethod(
buyer.change, new_mode, seller.eyes,
run_time=2,
rate_func=squish_rate_func(smooth, 0.5, 1),
),
ApplyMethod(
seller.change, "coin_flip_2", buyer.eyes,
rate_func=there_and_back,
),
]
return result
class IsSellerOne100(Scene):
def construct(self):
self.add_review()
self.show_probability()
self.show_random_numbers()
def add_review(self):
reviews = VGroup(*[TexMobject("\\checkmark") for x in range(10)])
reviews.arrange(RIGHT)
reviews.scale(2)
reviews.set_color(GREEN)
reviews.next_to(ORIGIN, UP)
blanks = VGroup(*[
Line(LEFT, RIGHT).match_width(rev).next_to(rev, DOWN, SMALL_BUFF)
for rev in reviews
])
blanks.shift(0.25 * reviews[0].get_width() * LEFT)
label = TextMobject(
" out of ",
)
tens = VGroup(*[Integer(10) for x in range(2)])
tens[0].next_to(label, LEFT)
tens[1].next_to(label, RIGHT)
tens.set_color(GREEN)
label.add(tens)
label.scale(2)
label.next_to(reviews, DOWN, LARGE_BUFF)
self.add(label)
self.add(blanks)
tens[0].to_count = reviews
self.play(
ShowIncreasingSubsets(reviews, int_func=np.ceil),
UpdateFromAlphaFunc(
tens[0],
lambda m, a: m.set_color(
interpolate_color(RED, GREEN, a)
).set_value(len(m.to_count))
),
run_time=2,
rate_func=bezier([0, 0, 1, 1]),
)
self.wait()
self.review_group = VGroup(reviews, blanks, label)
def show_probability(self):
review_group = self.review_group
prob_label = get_prob_positive_experience_label()
prob_label.add(TexMobject("=").next_to(prob_label, RIGHT))
rhs = DecimalNumber(1)
rhs.next_to(prob_label, RIGHT)
rhs.set_color(YELLOW)
prob_label.add(rhs)
prob_label.scale(2)
prob_label.to_corner(UL)
q_mark = TexMobject("?")
q_mark.set_color(YELLOW)
q_mark.match_height(rhs)
q_mark.reference = rhs
q_mark.add_updater(lambda m: m.next_to(m.reference, RIGHT))
rhs_rect = SurroundingRectangle(rhs, buff=0.2)
rhs_rect.set_color(RED)
not_necessarily = TextMobject("Not necessarily!")
not_necessarily.set_color(RED)
not_necessarily.scale(1.5)
not_necessarily.next_to(prob_label, DOWN, 1.5)
arrow = Arrow(
not_necessarily.get_top(),
rhs_rect.get_corner(DL),
buff=MED_SMALL_BUFF,
)
arrow.set_color(RED)
rhs.set_value(0)
self.play(
ChangeDecimalToValue(rhs, 1),
UpdateFromAlphaFunc(
prob_label,
lambda m, a: m.set_opacity(a),
),
FadeIn(q_mark),
)
self.wait()
self.play(
ShowCreation(rhs_rect),
Write(not_necessarily),
ShowCreation(arrow),
review_group.to_edge, DOWN,
run_time=1,
)
self.wait()
self.play(
ChangeDecimalToValue(rhs, 0.95),
FadeOut(rhs_rect),
FadeOut(arrow),
FadeOut(not_necessarily),
)
self.wait()
self.prob_label_group = VGroup(
prob_label, rhs, q_mark,
)
def show_random_numbers(self):
prob_label_group = self.prob_label_group
random.seed(2)
rows = VGroup(*[
VGroup(*[
Integer(
random.randint(0, 99)
).move_to(0.85 * x * RIGHT)
for x in range(10)
])
for y in range(10 * 2)
])
rows.arrange_in_grid(n_cols=2, buff=MED_LARGE_BUFF)
rows[:10].shift(LEFT)
rows.set_height(5.5)
rows.center().to_edge(DOWN)
lt_95 = VGroup(*[
mob
for row in rows
for mob in row
if mob.get_value() < 95
])
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square = Square()
square.set_stroke(width=0)
square.set_fill(YELLOW, 0.5)
square.set_width(1.5 * rows[0][0].get_height())
highlights = VGroup(*[
square.copy().move_to(mob)
for row in rows
for mob in row
if mob.get_value() < 95
])
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row_rects = VGroup(*[
SurroundingRectangle(row)
for row in rows
if all([m.get_value() < 95 for m in row])
])
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row_rects.set_stroke(GREEN, 2)
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self.play(
LaggedStartMap(
ShowIncreasingSubsets, rows,
run_time=3,
lag_ratio=0.25,
),
FadeOutAndShift(self.review_group, DOWN),
prob_label_group.set_height, 0.75,
prob_label_group.to_corner, UL,
)
self.wait()
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# self.add(highlights, rows)
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self.play(
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# FadeIn(highlights)
lt_95.set_fill, BLUE,
lt_95.set_stroke, BLUE, 2, {"background": True},
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)
self.wait()
self.play(LaggedStartMap(ShowCreation, row_rects))
self.wait()
class LookAtAllPossibleSuccessRates(Scene):
def construct(self):
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axes = get_beta_dist_axes(y_max=6, y_unit=1)
dist = scipy.stats.beta(10, 2)
graph = axes.get_graph(dist.pdf)
graph.set_stroke(BLUE, 3)
flat_graph = graph.copy()
flat_graph.points[:, 1] = axes.c2p(0, 0)[1]
flat_graph.set_stroke(YELLOW, 3)
x_labels = axes.x_axis.numbers
x_labels.set_opacity(0)
sellers = VGroup(*[
self.get_example_seller(label.get_value())
for label in x_labels
])
sellers.arrange(RIGHT, buff=LARGE_BUFF)
sellers.set_width(FRAME_WIDTH - 1)
sellers.to_edge(UP, buff=LARGE_BUFF)
sellers.generate_target()
for seller, label in zip(sellers.target, x_labels):
seller.next_to(label, DOWN)
seller[0].set_opacity(0)
seller[1].set_opacity(0)
seller[2].replace(label, dim_to_match=1)
x_label = TextMobject("All possible success rates")
x_label.next_to(axes.c2p(0.5, 0), UP)
x_label.shift(2 * LEFT)
y_axis_label = TextMobject(
"A kind of probability\\\\",
"of probabilities"
)
y_axis_label.scale(0.75)
y_axis_label.next_to(axes.y_axis, RIGHT)
y_axis_label.to_edge(UP)
y_axis_label[1].set_color(YELLOW)
graph_label = TextMobject(
"Some notion of likelihood\\\\",
"for each one"
)
graph_label[1].align_to(graph_label[0], LEFT)
graph_label.next_to(graph.get_boundary_point(UP), UP)
graph_label.shift(0.5 * DOWN)
graph_label.to_edge(RIGHT)
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x_axis_line = Line(axes.c2p(0, 0), axes.c2p(1, 0))
x_axis_line.set_stroke(YELLOW, 3)
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shuffled_sellers = VGroup(*sellers)
shuffled_sellers.shuffle()
self.play(GrowFromCenter(shuffled_sellers[0]))
self.play(LaggedStartMap(
FadeInFromPoint, shuffled_sellers[1:],
lambda m: (m, sellers.get_center())
))
self.wait()
self.play(
MoveToTarget(sellers),
FadeIn(axes),
run_time=2,
)
self.play(
x_label.shift, 4 * RIGHT,
UpdateFromAlphaFunc(
x_label,
lambda m, a: m.set_opacity(a),
rate_func=there_and_back,
),
ShowCreation(x_axis_line),
run_time=3,
)
self.play(FadeOut(x_axis_line))
self.wait()
self.play(
FadeInFromDown(graph_label),
ReplacementTransform(flat_graph, graph),
)
self.wait()
self.play(FadeInFromDown(y_axis_label))
# Show probabilities
x_tracker = ValueTracker(0.5)
prob_label = get_prob_positive_experience_label(True, True, True)
prob_label.next_to(axes.c2p(0, 2), RIGHT, MED_LARGE_BUFF)
prob_label.decimal.tracker = x_tracker
prob_label.decimal.add_updater(
lambda m: m.set_value(m.tracker.get_value())
)
v_line = Line(DOWN, UP)
v_line.set_stroke(YELLOW, 2)
v_line.tracker = x_tracker
v_line.graph = graph
v_line.axes = axes
v_line.add_updater(
lambda m: m.put_start_and_end_on(
m.axes.x_axis.n2p(m.tracker.get_value()),
m.axes.input_to_graph_point(m.tracker.get_value(), m.graph),
)
)
self.add(v_line)
for x in [0.95, 0.8, 0.9]:
self.play(
x_tracker.set_value, x,
run_time=4,
)
self.wait()
def get_example_seller(self, success_rate):
randy = Randolph(mode="coin_flip_1", height=1)
label = TexMobject("s = ")
decimal = DecimalNumber(success_rate)
decimal.match_height(label)
decimal.next_to(label[-1], RIGHT)
label.set_color(YELLOW)
decimal.set_color(YELLOW)
VGroup(label, decimal).next_to(randy, DOWN)
result = VGroup(randy, label, decimal)
result.randy = randy
result.label = label
result.decimal = decimal
return result
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class AskAboutUnknownProbabilities(Scene):
def construct(self):
# Setup
unknown_title, prob_title = titles = self.get_titles()
v_line = Line(UP, DOWN)
v_line.set_height(FRAME_HEIGHT)
v_line.set_stroke([WHITE, LIGHT_GREY], 3)
h_line = Line(LEFT, RIGHT)
h_line.set_width(FRAME_WIDTH)
h_line.next_to(titles, DOWN)
processes = VGroup(
get_random_coin(shuffle_time=1),
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get_random_die(shuffle_time=1.5),
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get_random_card(shuffle_time=2),
)
processes.arrange(DOWN, buff=0.7)
processes.next_to(unknown_title, DOWN, LARGE_BUFF)
processes_rect = BackgroundRectangle(processes)
processes_rect.set_fill(BLACK, 1)
prob_labels = VGroup(
TexMobject("P(", "00", ")", "=", "1 / 2"),
TexMobject("P(", "00", ")", "=", "1 / 6}"),
TexMobject("P(", "00", ")", "=", "1 / 52}"),
)
prob_labels.scale(1.5)
prob_labels.arrange(DOWN, aligned_edge=LEFT)
prob_labels.match_x(prob_title)
for pl, pr in zip(prob_labels, processes):
pl.match_y(pr)
content = pr[1].copy()
content.replace(pl[1], dim_to_match=0)
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pl.replace_submobject(1, content)
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# Putting numbers to the unknown
number_rects = VGroup(*[
SurroundingRectangle(pl[-1])
for pl in prob_labels
])
number_rects.set_stroke(YELLOW, 2)
for pl in prob_labels:
pl.save_state()
pl[:3].match_x(prob_title)
pl[3:].match_x(prob_title)
pl.set_opacity(0)
self.add(processes)
self.play(
LaggedStartMap(FadeInFromDown, titles),
LaggedStart(
ShowCreation(v_line),
ShowCreation(h_line),
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lag_ratio=0.1,
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),
LaggedStartMap(Restore, prob_labels),
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run_time=1
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)
self.wait(2)
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# self.play(
# LaggedStartMap(
# ShowCreationThenFadeOut,
# number_rects,
# run_time=3,
# )
# )
# self.wait(2)
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# Highlight coin flip
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fade_rects = VGroup(*[
VGroup(
BackgroundRectangle(pl, buff=MED_SMALL_BUFF),
BackgroundRectangle(pr, buff=MED_SMALL_BUFF),
)
for pl, pr in zip(prob_labels, processes)
])
fade_rects.set_fill(BLACK, 0.8)
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prob_half = prob_labels[0]
half = prob_half[-1]
half_underline = Line(LEFT, RIGHT)
half_underline.set_width(half.get_width() + MED_SMALL_BUFF)
half_underline.next_to(half, DOWN, buff=SMALL_BUFF)
half_underline.set_stroke(YELLOW, 3)
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self.play(
FadeIn(fade_rects[1]),
FadeIn(fade_rects[2]),
)
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self.wait(2)
self.play(
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FadeIn(fade_rects[0]),
FadeOut(fade_rects[1]),
)
self.wait(3)
self.play(
FadeOut(fade_rects[0]),
FadeOut(fade_rects[2]),
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)
self.wait(4)
# Transition to question
processes.suspend_updating()
self.play(
LaggedStart(
FadeOutAndShift(unknown_title, UP),
FadeOutAndShift(prob_title, UP),
lag_ratio=0.2,
),
FadeOutAndShift(h_line, UP, lag_ratio=0.1),
FadeOutAndShift(processes, LEFT, lag_ratio=0.1),
FadeOut(prob_labels[1]),
FadeOut(prob_labels[2]),
v_line.rotate, 90 * DEGREES,
v_line.shift, 0.6 * FRAME_HEIGHT * UP,
prob_half.center,
prob_half.to_edge, UP,
run_time=2,
)
self.clear()
self.add(prob_half)
arrow = Vector(UP)
arrow.next_to(half, DOWN)
question = TextMobject("What exactly does\\\\this mean?")
question.next_to(arrow, DOWN)
self.play(
GrowArrow(arrow),
FadeInFrom(question, UP),
)
self.wait(2)
self.play(
FadeOutAndShift(question, RIGHT),
Rotate(arrow, 90 * DEGREES),
VFadeOut(arrow),
)
# Show long run averages
self.show_many_coins(20, 50)
self.show_many_coins(40, 100)
# Make probability itself unknown
q_marks = TexMobject("???")
q_marks.set_color(YELLOW)
q_marks.replace(half, dim_to_match=0)
randy = Randolph(mode="confused")
randy.center()
randy.look_at(prob_half)
self.play(
FadeOutAndShift(half, UP),
FadeInFrom(q_marks, DOWN),
)
self.play(FadeIn(randy))
self.play(Blink(randy))
self.wait()
# self.embed()
def get_titles(self):
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unknown_label = TextMobject("Random process")
prob_label = TextMobject("Long-run frequency")
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titles = VGroup(unknown_label, prob_label)
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titles.scale(1.25)
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unknown_label.move_to(FRAME_WIDTH * LEFT / 4)
prob_label.move_to(FRAME_WIDTH * RIGHT / 4)
titles.to_edge(UP, buff=MED_SMALL_BUFF)
titles.set_color(BLUE)
return titles
def show_many_coins(self, n_rows, n_cols):
coin_choices = VGroup(
get_coin(BLUE_E, "H"),
get_coin(RED_E, "T"),
)
coin_choices.set_stroke(width=0)
coins = VGroup(*[
random.choice(coin_choices).copy()
for x in range(n_rows * n_cols)
])
def organize_coins(coin_group):
coin_group.scale(1 / coin_group[0].get_height())
coin_group.arrange_in_grid(n_rows=n_rows)
coin_group.set_width(FRAME_WIDTH - 1)
coin_group.to_edge(DOWN, MED_LARGE_BUFF)
organize_coins(coins)
sorted_coins = VGroup()
for coin in coins:
coin.generate_target()
sorted_coins.add(coin.target)
sorted_coins.submobjects.sort(key=lambda m: m.symbol)
organize_coins(sorted_coins)
self.play(LaggedStartMap(
FadeInFrom, coins,
lambda m: (m, 0.2 * DOWN),
run_time=3,
rate_func=linear
))
self.wait()
self.play(LaggedStartMap(
MoveToTarget, coins,
path_arc=30 * DEGREES,
run_time=2,
lag_ratio=1 / len(coins),
))
self.wait()
self.play(FadeOut(coins))
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class ComplainAboutSimplisticModel(TeacherStudentsScene):
def construct(self):
axes = self.get_experience_graph()
self.add(axes)
self.play(
self.teacher.change, "raise_right_hand", axes,
self.get_student_changes(
"pondering", "erm", "sassy",
look_at_arg=axes,
),
ShowCreation(
axes.graph,
run_time=3,
rate_func=linear,
),
)
self.wait(2)
student = self.students[2]
bubble = SpeechBubble(
direction=LEFT,
height=3,
width=5,
)
bubble.pin_to(student)
bubble.write("What about something\\\\like this?")
self.play(
axes.next_to, student, UL,
VFadeOut(axes.graph),
FadeIn(bubble),
Write(bubble.content, run_time=1),
student.change, "raise_left_hand",
self.students[0].change, "thinking", axes,
self.students[1].change, "thinking", axes,
self.teacher.change, "happy",
)
new_graph = VMobject()
new_graph.set_points_as_corners([
axes.c2p(0, 0.75),
axes.c2p(2, 0.9),
axes.c2p(4, 0.5),
axes.c2p(6, 0.75),
axes.c2p(8, 0.55),
axes.c2p(10, 0.95),
])
new_graph.make_smooth()
new_graph.set_stroke([YELLOW, RED, GREEN], 2)
self.play(
ShowCreation(new_graph),
*[
ApplyMethod(pi.look_at, new_graph)
for pi in self.pi_creatures
]
)
self.wait(3)
def get_experience_graph(self):
axes = Axes(
x_min=-1,
x_max=10,
y_min=0,
y_max=1.25,
y_axis_config={
"unit_size": 5,
"tick_frequency": 0.25,
"include_tip": False,
}
)
axes.set_stroke(LIGHT_GREY, 1)
axes.set_height(3)
y_label = TextMobject("Experience quality")
y_label.scale(0.5)
y_label.next_to(axes.y_axis.get_top(), RIGHT, SMALL_BUFF)
axes.add(y_label)
lines = VGroup()
for x in range(10):
lines.add(
Line(axes.c2p(x, 0), axes.c2p(x + 0.9, 0))
)
lines.set_stroke(RED, 3)
for line in lines:
if random.random() < 0.5:
line.set_y(axes.c2p(0, 1)[1])
line.set_stroke(GREEN)
axes.add(lines)
axes.graph = lines
rect = BackgroundRectangle(axes, buff=0.25)
rect.set_stroke(WHITE, 1)
rect.set_fill(BLACK, 1)
axes.add_to_back(rect)
axes.to_corner(UR)
return axes
class ComingUpWrapper(Scene):
def construct(self):
background = FullScreenFadeRectangle()
background.set_fill(GREY_E, 1)
title = TextMobject("What's coming...")
title.scale(1.5)
title.to_edge(UP)
rect = ScreenRectangle()
rect.set_height(6)
rect.set_stroke(WHITE)
rect.set_fill(BLACK, 1)
rect.next_to(title, DOWN)
self.add(background, rect)
self.play(FadeInFromDown(title))
self.wait()
class PreviewBeta(Scene):
def construct(self):
axes = get_beta_dist_axes(label_y=True)
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axes.y_axis.remove(axes.y_axis.numbers)
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marks = get_plusses_and_minuses(p=0.75)
marks.next_to(axes.y_axis.get_top(), DR, buff=0.75)
beta_label = get_beta_label(0, 0)
beta_label.next_to(marks, UR, buff=LARGE_BUFF)
beta_label.to_edge(UP)
bl_left = beta_label.get_left()
beta_container = VGroup()
graph_container = VGroup()
n_graphs = 2
for x in range(n_graphs):
graph_container.add(VMobject())
def get_counts(marks):
is_plusses = [m.is_plus for m in marks]
p = sum(is_plusses)
n = len(is_plusses) - p
return p, n
def update_beta(container):
counts = get_counts(marks)
new_label = get_beta_label(*counts)
new_label.move_to(bl_left, LEFT)
container.set_submobjects([new_label])
return container
def update_graph(container):
counts = get_counts(marks)
new_graph = get_beta_graph(axes, *counts)
new_graphs = [*container[1:], new_graph]
for g, a in zip(new_graphs, np.linspace(0.2, 1, n_graphs)):
g.set_opacity(a)
container.set_submobjects(new_graphs)
return container
self.add(axes)
self.play(
ShowIncreasingSubsets(marks),
UpdateFromFunc(
beta_container,
update_beta,
),
UpdateFromFunc(
graph_container,
update_graph,
),
run_time=15,
rate_func=bezier([0, 0, 1, 1]),
)
self.wait()
class AskInverseQuestion(WhatsTheModel):
def construct(self):
self.force_skipping()
self.introduce_buyer_and_seller()
self.bs_group = VGroup(
self.buyer,
self.seller,
self.buyer.label,
self.seller.label,
)
self.bs_group.to_edge(DOWN)
self.revert_to_original_skipping_status()
self.add_probability_label()
self.show_many_review_animations()
self.ask_question()
def add_probability_label(self):
label = get_prob_positive_experience_label(True, True, False)
label.decimal.set_value(0.95)
label.next_to(self.seller, UP, aligned_edge=LEFT, buff=MED_LARGE_BUFF)
self.add(label)
self.probability_label = label
def show_many_review_animations(self):
for x in range(7):
self.play(*self.experience_animations(
self.seller,
self.buyer,
arc=30 * DEGREES,
p=0.95,
))
def ask_question(self):
pis = [self.buyer, self.seller]
labels = VGroup(
self.get_prob_review_label(10, 0),
self.get_prob_review_label(48, 2),
self.get_prob_review_label(184, 16),
)
labels.arrange(DOWN)
labels.to_edge(UP)
labels[0].save_state()
labels[0].set_opacity(0)
words = labels[0][-3:-1]
words.set_opacity(1)
words.scale(1.5)
words.center().to_edge(UP)
self.play(
FadeInFromDown(words),
)
self.wait()
self.play(
Restore(labels[0]),
*[
ApplyMethod(pi.change, 'pondering', labels)
for pi in pis
]
)
self.play(Blink(pis[0]))
self.play(Blink(pis[1]))
self.play(LaggedStartMap(FadeInFromDown, labels[1:]))
self.wait(2)
# Succinct
short_label = TexMobject(
"P(\\text{data} | s)",
tex_to_color_map={
"\\text{data}": LIGHT_GREY,
"s": YELLOW
}
)
short_label.scale(2)
short_label.next_to(labels, DOWN, LARGE_BUFF),
rect = SurroundingRectangle(short_label, buff=MED_SMALL_BUFF)
bs_group = self.bs_group
bs_group.add(self.probability_label)
self.play(
FadeInFrom(short_label, UP),
bs_group.scale, 0.5, {"about_edge": DOWN},
)
self.play(ShowCreation(rect))
self.wait()
def get_prob_review_label(self, n_positive, n_negative):
label = TexMobject(
"P(",
f"{n_positive}\\,{CMARK_TEX}", ",\\,",
f"{n_negative}\\,{XMARK_TEX}",
"\\,\\text{ Given that }",
"s = 0.95",
")",
)
label.set_color_by_tex_to_color_map({
CMARK_TEX: GREEN,
XMARK_TEX: RED,
"0.95": YELLOW,
})
return label
class SimulationsOf10Reviews(Scene):
CONFIG = {
"s": 0.95
}
def construct(self):
s_label = TexMobject("s = 0.95")
s_label.set_height(0.3)
s_label.to_corner(UL, buff=MED_SMALL_BUFF)
s_label.set_color(YELLOW)
self.add(s_label)
self.camera.frame.shift(LEFT)
s_label.shift(LEFT)
np.random.seed(6)
row = get_random_lt100_row(self.s)
count = self.get_count(row)
count.add_updater(
lambda m: m.set_value(
sum([s.positive for s in row.syms])
)
)
def update_nums(nums):
for num in nums:
num.set_value(np.random.randint(0, 100))
row.nums.save_state()
row.nums.set_color(WHITE)
self.play(
UpdateFromFunc(row.nums, update_nums),
run_time=2,
)
row.nums.restore()
self.wait()
self.add(count)
self.play(
ShowIncreasingSubsets(row.syms),
run_time=2,
rate_func=linear,
)
count.clear_updaters()
self.wait()
# Histogram
data = np.zeros(11)
histogram = Histogram(
data,
bar_colors=[RED, RED, BLUE, GREEN]
)
histogram.to_edge(DOWN)
histogram.axes.y_labels.set_opacity(0)
histogram.axes.h_lines.set_opacity(0)
stacks = VGroup()
for bar in histogram.bars:
stacks.add(VGroup(bar.copy()))
def put_into_histogram(row_count_group):
row, count = row_count_group
count.clear_updaters()
index = int(count.get_value())
stack = stacks[index]
row.set_width(stack.get_width() - SMALL_BUFF)
row.next_to(stack, UP, SMALL_BUFF)
count.replace(histogram.axes.x_labels[index])
stack.add(row)
return row_count_group
self.play(
FadeIn(histogram),
ApplyFunction(
put_into_histogram,
VGroup(row, count),
)
)
self.wait()
for x in range(2):
row = get_random_lt100_row(self.s)
count = self.get_count(row)
group = VGroup(row, count)
self.play(FadeIn(group, lag_ratio=0.2))
self.wait(0.5)
self.play(
ApplyFunction(
put_into_histogram,
VGroup(row, count),
)
)
for x in range(40):
row = get_random_lt100_row(self.s)
count = self.get_count(row)
lower_group = VGroup(row, count).copy()
put_into_histogram(lower_group)
self.add(row, count, lower_group)
self.wait(0.1)
self.remove(row, count)
data = np.array([len(stack) - 1 for stack in stacks])
self.add(row, count)
self.play(
FadeOut(stacks),
FadeOut(count),
histogram.bars.become, histogram.get_bars(data),
histogram.axes.y_labels.set_opacity, 1,
histogram.axes.h_lines.set_opacity, 1,
histogram.axes.y_axis.set_opacity, 1,
)
self.remove(stacks)
arrow = Vector(0.5 * DOWN)
arrow.set_stroke(width=5)
arrow.set_color(YELLOW)
arrow.next_to(histogram.bars[10], UP, SMALL_BUFF)
def update(dummy):
new_row = get_random_lt100_row(self.s)
row.become(new_row)
count = sum([m.positive for m in new_row.nums])
data[count] += 1
histogram.bars.become(histogram.get_bars(data))
arrow.next_to(histogram.bars[count], UP, SMALL_BUFF)
self.add(arrow)
self.play(
UpdateFromFunc(Group(row, arrow, histogram.bars), update),
run_time=10,
)
#
def get_count(self, row):
count = Integer()
count.set_height(0.75)
count.next_to(row, DOWN, buff=0.65)
count.set_value(sum([s.positive for s in row.syms]))
return count
class SimulationsOf50Reviews(Scene):
CONFIG = {
"s": 0.95,
"histogram_config": {
"x_label_freq": 5,
"y_axis_numbers_to_show": range(10, 70, 10),
"y_max": 0.6,
"y_tick_freq": 0.1,
"height": 5,
"bar_colors": [BLUE],
},
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"random_seed": 1,
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}
def construct(self):
self.add_s_label()
data = np.zeros(51)
histogram = self.get_histogram(data)
row = self.get_row()
count = self.get_count(row)
original_count = count.get_value()
count.set_value(0)
self.add(histogram)
self.play(
ShowIncreasingSubsets(row),
ChangeDecimalToValue(count, original_count)
)
# Run many samples
arrow = Vector(0.5 * DOWN)
arrow.set_stroke(width=5)
arrow.set_color(YELLOW)
arrow.next_to(histogram.bars[10], UP, SMALL_BUFF)
total_data_label = VGroup(
TextMobject("Total samples: "),
Integer(1),
)
total_data_label.arrange(RIGHT)
total_data_label.next_to(row, DOWN)
total_data_label.add_updater(
lambda m: m[1].set_value(data.sum())
)
def update(dummy, n_added_data_points=0):
new_row = self.get_row()
row.become(new_row)
num_positive = sum([m.positive for m in new_row])
count.set_value(num_positive)
data[num_positive] += 1
if n_added_data_points:
values = np.random.random((n_added_data_points, 50))
counts = (values < self.s).sum(1)
for i in range(len(data)):
data[i] += (counts == i).sum()
histogram.bars.become(histogram.get_bars(data))
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histogram.bars.set_fill(GREY_C)
histogram.bars[48].set_fill(GREEN)
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arrow.next_to(histogram.bars[num_positive], UP, SMALL_BUFF)
self.add(arrow, total_data_label)
group = VGroup(histogram.bars, row, count, arrow)
self.play(
UpdateFromFunc(group, update),
run_time=4
)
self.play(
UpdateFromFunc(
group,
lambda m: update(m, 1000)
),
run_time=4
)
random.seed(0)
np.random.seed(0)
update(group)
self.wait()
# Show 48 bar
axes = histogram.axes
y = choose(50, 48) * (self.s)**48 * (1 - self.s)**2
line = DashedLine(
axes.c2p(0, y),
axes.c2p(51, y),
)
label = TexMobject("{:.1f}\\%".format(100 * y))
fix_percent(label.family_members_with_points()[-1])
label.next_to(line, RIGHT)
self.play(
ShowCreation(line),
FadeInFromPoint(label, line.get_start())
)
def add_s_label(self):
s_label = TexMobject("s = 0.95")
s_label.set_height(0.3)
s_label.to_corner(UL, buff=MED_SMALL_BUFF)
s_label.shift(0.8 * DOWN)
s_label.set_color(YELLOW)
self.add(s_label)
def get_histogram(self, data):
histogram = Histogram(
data, **self.histogram_config
)
histogram.to_edge(DOWN)
return histogram
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def get_row(self, n=50):
row = get_random_checks_and_crosses(n, self.s)
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row.to_edge(UP)
return row
def get_count(self, row):
count = Integer(sum([m.positive for m in row]))
count.set_height(0.3)
count.next_to(row, RIGHT)
return count
class ShowBinomialFormula(SimulationsOf50Reviews):
CONFIG = {
"histogram_config": {
"x_label_freq": 5,
"y_axis_numbers_to_show": range(10, 40, 10),
"y_max": 0.3,
"y_tick_freq": 0.1,
"height": 2.5,
"bar_colors": [BLUE],
},
"random_seed": 0,
}
def construct(self):
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# Add histogram
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dist = scipy.stats.binom(50, self.s)
data = np.array([
dist.pmf(x)
for x in range(0, 51)
])
histogram = self.get_histogram(data)
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histogram.bars.set_fill(GREY_C)
histogram.bars[48].set_fill(GREEN)
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self.add(histogram)
row = self.get_row()
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self.add(row)
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# Formula
prob_label = get_prob_review_label(48, 2)
eq = TexMobject("=")
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formula = get_binomial_formula(50, 48, self.s)
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equation = VGroup(
prob_label,
eq,
formula,
)
equation.arrange(RIGHT)
equation.next_to(histogram, UP, LARGE_BUFF)
equation.to_edge(RIGHT)
prob_label.save_state()
arrow = Vector(DOWN)
arrow.next_to(histogram.bars[48], UP, SMALL_BUFF)
prob_label.next_to(arrow, UP)
self.play(
FadeIn(prob_label),
GrowArrow(arrow),
)
for mob in prob_label[1::2]:
line = Underline(mob)
line.match_color(mob)
self.play(ShowCreationThenDestruction(line))
self.wait(0.5)
self.play(
Restore(prob_label),
FadeIn(equation[1:], lag_ratio=0.1),
)
self.wait()
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self.explain_n_choose_k(row, formula)
# Circle formula parts
rect1 = SurroundingRectangle(formula[4:8])
rect2 = SurroundingRectangle(formula[8:])
rect1.set_stroke(GREEN, 2)
rect2.set_stroke(RED, 2)
for rect in rect1, rect2:
self.play(ShowCreation(rect))
self.wait()
self.play(FadeOut(rect))
# Show numerical answer
eq2 = TexMobject("=")
value = DecimalNumber(dist.pmf(48), num_decimal_places=5)
rhs = VGroup(eq2, value)
rhs.arrange(RIGHT)
rhs.match_y(eq)
rhs.to_edge(RIGHT, buff=MED_SMALL_BUFF)
self.play(
FadeInFrom(value, LEFT),
FadeIn(eq2),
equation.next_to, eq2, LEFT,
)
self.wait()
# Show alternate values of k
n = 50
for k in it.chain(range(47, 42, -1), range(43, 51), [49, 48]):
new_prob_label = get_prob_review_label(k, n - k)
new_prob_label.replace(prob_label)
prob_label.become(new_prob_label)
new_formula = get_binomial_formula(n, k, self.s)
new_formula.replace(formula)
formula.set_submobjects(new_formula)
value.set_value(dist.pmf(k))
histogram.bars.set_fill(LIGHT_GREY)
histogram.bars[k].set_fill(GREEN)
arrow.next_to(histogram.bars[k], UP, SMALL_BUFF)
new_row = get_checks_and_crosses((n - k) * [False] + k * [True])
new_row.replace(row)
row.become(new_row)
self.wait(0.5)
# Name it as the Binomial distribution
long_equation = VGroup(prob_label, eq, formula, eq2, value)
bin_name = TextMobject("Binomial", " Distribution")
bin_name.scale(1.5)
bin_name.next_to(histogram, UP, MED_LARGE_BUFF)
underline = Underline(bin_name[0])
underline.set_stroke(PINK, 2)
nck_rect = SurroundingRectangle(formula[:4])
nck_rect.set_stroke(PINK, 2)
self.play(
long_equation.next_to, self.slots, DOWN, MED_LARGE_BUFF,
long_equation.to_edge, RIGHT,
FadeInFrom(bin_name, DOWN),
)
self.wait()
self.play(ShowCreationThenDestruction(underline))
self.wait()
bools = [True] * 50
bools[random.randint(0, 49)] = False
bools[random.randint(0, 49)] = False
row.become(get_checks_and_crosses(bools).replace(row))
self.play(ShowIncreasingSubsets(row, run_time=4))
self.wait()
# Show likelihood and posterior labels
likelihood_label = TexMobject(
"P(",
"\\text{data}", "\\,|\\,",
"\\text{success rate}",
")",
)
posterior_label = TexMobject(
"P(",
"\\text{success rate}",
"\\,|\\,",
"\\text{data}",
")",
)
for label in (likelihood_label, posterior_label):
label.set_color_by_tex_to_color_map({
"data": GREEN,
"success": YELLOW,
})
likelihood_label.next_to(
prob_label, DOWN, LARGE_BUFF, aligned_edge=LEFT
)
right_arrow = Vector(RIGHT)
right_arrow.next_to(likelihood_label, RIGHT)
ra_label = TextMobject("But we want")
ra_label.match_width(right_arrow)
ra_label.next_to(right_arrow, UP, SMALL_BUFF)
posterior_label.next_to(right_arrow, RIGHT)
self.play(
FadeInFrom(likelihood_label, UP),
bin_name.set_height, 0.4,
bin_name.set_y, histogram.axes.c2p(0, .25)[1]
)
self.wait()
self.play(
GrowArrow(right_arrow),
FadeInFrom(ra_label, 0.5 * LEFT),
)
anims = []
for i, j in enumerate([0, 3, 2, 1, 4]):
anims.append(
TransformFromCopy(
likelihood_label[i],
posterior_label[j],
path_arc=-45 * DEGREES,
run_time=2,
)
)
self.play(*anims)
self.add(posterior_label)
self.wait()
# Prepare for new plot
histogram.add(bin_name)
always(arrow.next_to, histogram.bars[48], UP, SMALL_BUFF)
self.play(
FadeOut(likelihood_label),
FadeOut(posterior_label),
FadeOut(right_arrow),
FadeOut(ra_label),
FadeOutAndShift(row, UP),
FadeOutAndShift(self.slots, UP),
histogram.scale, 0.7,
histogram.to_edge, UP,
arrow.scale, 0.5,
arrow.set_stroke, None, 4,
long_equation.center,
run_time=1.5,
)
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self.add(arrow)
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# x_labels = histogram.axes.x_labels
# underline = Underline(x_labels)
# underline.set_stroke(GREEN, 3)
# self.play(
# LaggedStartMap(
# ApplyFunction, x_labels,
# lambda mob: (
# lambda m: m.scale(1.5).set_color(GREEN),
# mob,
# ),
# rate_func=there_and_back,
# ),
# ShowCreationThenDestruction(underline),
# )
# num_checks = TexMobject("\\# " + CMARK_TEX)
# num_checks.set_color(GREEN)
# num_checks.next_to(
# x_labels, RIGHT,
# MED_LARGE_BUFF,
# aligned_edge=DOWN,
# )
# self.play(Write(num_checks))
# self.wait()
low_axes = get_beta_dist_axes(y_max=0.3, y_unit=0.1, label_y=False)
low_axes.y_axis.set_height(
2,
about_point=low_axes.c2p(0, 0),
stretch=True,
)
low_axes.to_edge(DOWN)
low_axes.x_axis.numbers.set_color(YELLOW)
y_label_copies = histogram.axes.y_labels.copy()
y_label_copies.set_height(0.6 * low_axes.get_height())
y_label_copies.next_to(low_axes, LEFT, 0, aligned_edge=UP)
y_label_copies.shift(SMALL_BUFF * UP)
low_axes.y_axis.add(y_label_copies)
low_axes.y_axis.set_opacity(0)
# Show alternate values of s
s_tracker = ValueTracker(self.s)
s_tip = ArrowTip(start_angle=-90 * DEGREES)
s_tip.set_color(YELLOW)
s_tip.axis = low_axes.x_axis
s_tip.st = s_tracker
s_tip.add_updater(
lambda m: m.next_to(m.axis.n2p(m.st.get_value()), UP, buff=0)
)
pl_decimal = DecimalNumber(self.s)
pl_decimal.set_color(YELLOW)
pl_decimal.replace(prob_label[-2][2:])
prob_label[-2][2:].set_opacity(0)
s_label = VGroup(prob_label[-2][:2], pl_decimal).copy()
sl_rect = SurroundingRectangle(s_label)
sl_rect.set_stroke(YELLOW, 2)
self.add(pl_decimal)
self.play(
ShowCreation(sl_rect),
Write(low_axes),
)
self.play(
s_label.next_to, s_tip, UP, 0.2, ORIGIN, s_label[1],
ReplacementTransform(sl_rect, s_tip)
)
always(s_label.next_to, s_tip, UP, 0.2, ORIGIN, s_label[1])
decimals = VGroup(pl_decimal, s_label[1], formula[5], formula[9])
decimals.s_tracker = s_tracker
histogram.s_tracker = s_tracker
histogram.n = n
histogram.rhs_value = value
def update_decimals(decs):
for dec in decs:
dec.set_value(decs.s_tracker.get_value())
def update_histogram(hist):
new_dist = scipy.stats.binom(hist.n, hist.s_tracker.get_value())
new_data = np.array([
new_dist.pmf(x)
for x in range(0, 51)
])
new_bars = hist.get_bars(new_data)
new_bars.match_style(hist.bars)
hist.bars.become(new_bars)
hist.rhs_value.set_value(new_dist.pmf(48))
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bar_copy = histogram.bars[48].copy()
value.initial_config["num_decimal_places"] = 2
value.set_value(value.get_value())
bar_copy.next_to(value, RIGHT, aligned_edge=DOWN)
bar_copy.add_updater(
lambda m: m.set_height(
max(
histogram.bars[48].get_height() * 0.75,
1e-6,
),
stretch=True,
about_edge=DOWN,
)
)
self.add(bar_copy)
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self.add(histogram)
self.add(decimals)
for s in [0.95, 0.5, 0.99, 0.9]:
self.play(
s_tracker.set_value, s,
UpdateFromFunc(decimals, update_decimals),
UpdateFromFunc(histogram, update_histogram),
UpdateFromFunc(value, lambda m: m),
UpdateFromFunc(s_label, lambda m: m.update),
run_time=5,
)
self.wait()
# Plot
def func(x):
return scipy.stats.binom(50, x).pmf(48) + 1e-5
graph = low_axes.get_graph(func, step_size=0.05)
graph.set_stroke(BLUE, 3)
v_line = Line(DOWN, UP)
v_line.axes = low_axes
v_line.st = s_tracker
v_line.graph = graph
v_line.add_updater(
lambda m: m.put_start_and_end_on(
m.axes.c2p(m.st.get_value(), 0),
m.axes.input_to_graph_point(
m.st.get_value(),
m.graph,
),
)
)
v_line.set_stroke(GREEN, 2)
dot = Dot()
dot.line = v_line
dot.set_height(0.05)
dot.add_updater(lambda m: m.move_to(m.line.get_end()))
self.play(
ApplyMethod(
histogram.bars[48].stretch, 2, 1, {"about_edge": DOWN},
rate_func=there_and_back,
run_time=2,
),
)
self.wait()
self.play(low_axes.y_axis.set_opacity, 1)
self.play(
FadeIn(graph),
FadeOut(s_label),
FadeOut(s_tip),
)
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self.play(
TransformFromCopy(histogram.bars[48], v_line),
FadeIn(dot),
)
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self.add(histogram)
decimals.remove(decimals[1])
for s in [0.9, 0.96, 1, 0.8, 0.96]:
self.play(
s_tracker.set_value, s,
UpdateFromFunc(decimals, update_decimals),
UpdateFromFunc(histogram, update_histogram),
UpdateFromFunc(value, lambda m: m),
run_time=5,
)
self.wait()
def explain_n_choose_k(self, row, formula):
row.add_updater(lambda m: m)
brace = Brace(formula[:4], UP, buff=SMALL_BUFF)
words = brace.get_text("``50 choose 48''")
slots = self.slots = VGroup()
for sym in row:
line = Underline(sym)
line.scale(0.9)
slots.add(line)
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for slot in slots:
slot.match_y(slots[0])
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formula[1].counted = slots
k_rect = SurroundingRectangle(formula[2])
k_rect.set_stroke(GREEN, 2)
checks = VGroup()
for sym in row:
if sym.positive:
checks.add(sym)
self.play(
GrowFromCenter(brace),
FadeInFromDown(words),
)
self.wait()
self.play(FadeOut(words))
formula.save_state()
self.play(
ShowIncreasingSubsets(slots),
UpdateFromFunc(
formula[1],
lambda m: m.set_value(len(m.counted))
),
run_time=2,
)
formula.restore()
self.add(formula)
self.wait()
self.play(
LaggedStartMap(
ApplyMethod, checks,
lambda m: (m.shift, 0.3 * DOWN),
rate_func=there_and_back,
lag_ratio=0.05,
),
ShowCreationThenFadeOut(k_rect),
run_time=2,
)
self.remove(checks)
self.add(row)
self.wait()
# Example orderings
row_target = VGroup()
for sym in row:
sym.generate_target()
row_target.add(sym.target)
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row_target.sort(submob_func=lambda m: -int(m.positive))
row_target.arrange(
RIGHT, buff=get_norm(row[0].get_right() - row[1].get_left())
)
row_target.move_to(row)
self.play(
LaggedStartMap(
MoveToTarget, row,
path_arc=30 * DEGREES,
lag_ratio=0,
),
)
self.wait()
row.sort()
self.play(Swap(*row[-3:-1]))
self.add(row)
self.wait()
# All orderings
nck_count = Integer(2)
nck_count.next_to(brace, UP)
nck_top = nck_count.get_top()
always(nck_count.move_to, nck_top, UP)
combs = list(it.combinations(range(50), 48))
bool_lists = [
[i in comb for i in range(50)]
for comb in combs
]
row.counter = nck_count
row.bool_lists = bool_lists
def update_row(r):
i = r.counter.get_value() - 1
new_row = get_checks_and_crosses(r.bool_lists[i])
new_row.replace(r, dim_to_match=0)
r.set_submobjects(new_row)
row.add_updater(update_row)
self.add(row)
self.play(
ChangeDecimalToValue(nck_count, choose(50, 48)),
run_time=10,
)
row.clear_updaters()
self.wait()
self.play(
FadeOut(nck_count),
FadeOut(brace),
)
class WriteLikelihoodFunction(Scene):
def construct(self):
formula = TexMobject(
"f({s}) = (\\text{const.})",
"{s}^{\\#" + CMARK_TEX + "}",
"(1 - {s})^{\\#" + XMARK_TEX, "}",
tex_to_color_map={
"{s}": YELLOW,
"\\#" + CMARK_TEX: GREEN,
"\\#" + XMARK_TEX: RED,
}
)
formula.scale(2)
rect1 = SurroundingRectangle(formula[3:6])
rect2 = SurroundingRectangle(formula[6:])
self.play(FadeInFromDown(formula))
self.wait()
self.play(ShowCreationThenFadeOut(rect1))
self.wait()
self.play(ShowCreationThenFadeOut(rect2))
self.wait()
self.add(formula)
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self.embed()
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class LikelihoodGraphFor10of10(ShowBinomialFormula):
CONFIG = {
"histogram_config": {
"x_label_freq": 2,
"y_axis_numbers_to_show": range(25, 125, 25),
"y_max": 1,
"y_tick_freq": 0.25,
"height": 2,
"bar_colors": [BLUE],
},
}
def construct(self):
# Add histogram
dist = scipy.stats.binom(10, self.s)
data = np.array([
dist.pmf(x)
for x in range(0, 11)
])
histogram = self.get_histogram(data)
histogram.bars.set_fill(GREY_C)
histogram.bars[10].set_fill(GREEN)
histogram.to_edge(UP)
x_label = TexMobject("\\#" + CMARK_TEX)
x_label.set_color(GREEN)
x_label.next_to(histogram.axes.x_axis.get_end(), RIGHT)
histogram.add(x_label)
self.add(histogram)
# Add formula
prob_label = get_prob_review_label(10, 0)
eq = TexMobject("=")
formula = get_binomial_formula(10, 10, self.s)
eq2 = TexMobject("=")
value = DecimalNumber(dist.pmf(10), num_decimal_places=2)
equation = VGroup(prob_label, eq, formula, eq2, value)
equation.arrange(RIGHT)
equation.next_to(histogram, DOWN, MED_LARGE_BUFF)
arrow = Vector(DOWN)
arrow.next_to(histogram.bars[10], UP, SMALL_BUFF)
self.add(equation)
self.add(arrow)
# Add lower axes
low_axes = get_beta_dist_axes(y_max=1, y_unit=0.25, label_y=False)
low_axes.y_axis.set_height(
2,
about_point=low_axes.c2p(0, 0),
stretch=True,
)
low_axes.to_edge(DOWN)
low_axes.x_axis.numbers.set_color(YELLOW)
y_label_copies = histogram.axes.y_labels.copy()
y_label_copies.set_height(0.7 * low_axes.get_height())
y_label_copies.next_to(low_axes, LEFT, 0, aligned_edge=UP)
y_label_copies.shift(SMALL_BUFF * UP)
low_axes.y_axis.add(y_label_copies)
self.add(low_axes)
# Add lower plot
s_tracker = ValueTracker(self.s)
def func(x):
return x**10
graph = low_axes.get_graph(func, step_size=0.05)
graph.set_stroke(BLUE, 3)
v_line = Line(DOWN, UP)
v_line.axes = low_axes
v_line.st = s_tracker
v_line.graph = graph
v_line.add_updater(
lambda m: m.put_start_and_end_on(
m.axes.c2p(m.st.get_value(), 0),
m.axes.input_to_graph_point(
m.st.get_value(),
m.graph,
),
)
)
v_line.set_stroke(GREEN, 2)
dot = Dot()
dot.line = v_line
dot.set_height(0.05)
dot.add_updater(lambda m: m.move_to(m.line.get_end()))
self.add(graph, v_line, dot)
# Show simpler formula
brace = Brace(formula, DOWN, buff=SMALL_BUFF)
simpler_formula = TexMobject("s", "^{10}")
simpler_formula.set_color_by_tex("s", YELLOW)
simpler_formula.set_color_by_tex("10", GREEN)
simpler_formula.next_to(brace, DOWN)
rects = VGroup(
BackgroundRectangle(formula[:4]),
BackgroundRectangle(formula[8:]),
)
rects.set_opacity(0.75)
self.wait()
self.play(FadeIn(rects))
self.play(
GrowFromCenter(brace),
FadeInFrom(simpler_formula, UP)
)
self.wait()
# Show various values of s
pl_decimal = DecimalNumber(self.s)
pl_decimal.set_color(YELLOW)
pl_decimal.replace(prob_label[-2][2:])
prob_label[-2][2:].set_opacity(0)
decimals = VGroup(pl_decimal, formula[5], formula[9])
decimals.s_tracker = s_tracker
histogram.s_tracker = s_tracker
histogram.n = 10
histogram.rhs_value = value
def update_decimals(decs):
for dec in decs:
dec.set_value(decs.s_tracker.get_value())
def update_histogram(hist):
new_dist = scipy.stats.binom(hist.n, hist.s_tracker.get_value())
new_data = np.array([
new_dist.pmf(x)
for x in range(0, 11)
])
new_bars = hist.get_bars(new_data)
new_bars.match_style(hist.bars)
hist.bars.become(new_bars)
hist.rhs_value.set_value(new_dist.pmf(10))
self.add(histogram)
self.add(decimals, rects)
always(arrow.next_to, histogram.bars[10], UP, SMALL_BUFF)
for s in [0.8, 1]:
self.play(
s_tracker.set_value, s,
UpdateFromFunc(decimals, update_decimals),
UpdateFromFunc(histogram, update_histogram),
UpdateFromFunc(value, lambda m: m),
run_time=5,
)
self.wait()
class StateNeedForBayesRule(TeacherStudentsScene):
def construct(self):
axes = get_beta_dist_axes(y_max=1, y_unit=0.25, label_y=False)
axes.y_axis.set_height(
2,
about_point=axes.c2p(0, 0),
stretch=True,
)
axes.set_width(5)
graph = axes.get_graph(lambda x: x**10)
graph.set_stroke(BLUE, 3)
alt_graph = graph.copy()
alt_graph.add_line_to(axes.c2p(1, 0))
alt_graph.add_line_to(axes.c2p(0, 0))
alt_graph.set_stroke(width=0)
alt_graph.set_fill(BLUE_E, 1)
plot = VGroup(axes, alt_graph, graph)
student0, student1, student2 = self.students
plot.next_to(student2.get_corner(UL), UP, MED_LARGE_BUFF)
plot.shift(LEFT)
v_lines = VGroup(
DashedLine(axes.c2p(0.8, 0), axes.c2p(0.8, 1)),
DashedLine(axes.c2p(1, 0), axes.c2p(1, 1)),
)
v_lines.set_stroke(YELLOW, 2)
self.play(
LaggedStart(
ApplyMethod(student0.change, "pondering", plot),
ApplyMethod(student1.change, "pondering", plot),
ApplyMethod(student2.change, "raise_left_hand", plot),
),
FadeInFrom(plot, DOWN),
run_time=1.5
)
self.play(*map(ShowCreation, v_lines))
self.play(
self.teacher.change, "tease",
*[
ApplyMethod(
v_line.move_to,
axes.c2p(0.9, 0),
DOWN,
)
for v_line in v_lines
]
)
self.change_student_modes(
"thinking", "thinking", "pondering",
look_at_arg=v_lines,
)
self.wait(3)
self.teacher_says(
"First we need\\\\Bayes' rule",
added_anims=[
FadeOutAndShift(plot, LEFT),
FadeOutAndShift(v_lines, LEFT),
self.get_student_changes(
"pondering", "thinking", "pondering",
look_at_arg=self.teacher.eyes,
)
]
)
self.change_all_student_modes("hooray")
self.wait(2)
class ShowBayesRule(Scene):
def construct(self):
hyp = "\\text{Hypothesis}"
data = "\\text{Data}"
bayes = TexMobject(
f"P({hyp} \\,|\\, {data})", "=", "{",
f"P({data} \\,|\\, {hyp})", f"P({hyp})",
"\\over", f"P({data})",
tex_to_color_map={
hyp: YELLOW,
data: GREEN,
}
)
title = TextMobject("Bayes' rule")
title.scale(2)
title.to_edge(UP)
self.add(title)
self.add(*bayes[:5])
self.wait()
self.play(
*[
TransformFromCopy(bayes[i], bayes[j], path_arc=30 * DEGREES)
for i, j in [
(0, 7),
(1, 10),
(2, 9),
(3, 8),
(4, 11),
]
],
FadeIn(bayes[5]),
run_time=1.5
)
self.wait()
self.play(
*[
TransformFromCopy(bayes[i], bayes[j], path_arc=30 * DEGREES)
for i, j in [
(0, 12),
(1, 13),
(4, 14),
(0, 16),
(3, 17),
(4, 18),
]
],
FadeIn(bayes[15]),
run_time=1.5
)
self.add(bayes)
self.wait()
hyp_word = bayes.get_part_by_tex(hyp)
example_hyp = TextMobject(
"For example,\\\\",
"$0.9 < s < 0.99$",
)
example_hyp[1].set_color(YELLOW)
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example_hyp.next_to(hyp_word, DOWN, buff=1.5)
data_word = bayes.get_part_by_tex(data)
example_data = TexMobject(
"48\\,", CMARK_TEX,
"\\,2\\,", XMARK_TEX,
)
example_data.set_color_by_tex(CMARK_TEX, GREEN)
example_data.set_color_by_tex(XMARK_TEX, RED)
example_data.scale(1.5)
example_data.next_to(example_hyp, RIGHT, buff=1.5)
hyp_arrow = Arrow(
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hyp_word.get_bottom(),
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example_hyp.get_top(),
)
data_arrow = Arrow(
data_word.get_bottom(),
example_data.get_top(),
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)
self.play(
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GrowArrow(hyp_arrow),
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FadeInFromPoint(example_hyp, hyp_word.get_center()),
)
self.wait()
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self.play(
GrowArrow(data_arrow),
FadeInFromPoint(example_data, data_word.get_center()),
)
self.wait()
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class VisualizeBayesRule(Scene):
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def construct(self):
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self.show_continuum()
self.show_arrows()
self.show_discrete_probabilities()
self.show_bayes_formula()
self.parallel_universes()
self.update_from_data()
def show_continuum(self):
axes = get_beta_dist_axes(y_max=1, y_unit=0.1)
axes.y_axis.add_numbers(
*np.arange(0.2, 1.2, 0.2),
number_config={
"num_decimal_places": 1,
}
)
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p_label = TexMobject(
"P(s \\,|\\, \\text{data})",
tex_to_color_map={
"s": YELLOW,
"\\text{data}": GREEN,
}
)
p_label.scale(1.5)
p_label.to_edge(UP, LARGE_BUFF)
s_part = p_label.get_part_by_tex("s").copy()
x_line = Line(axes.c2p(0, 0), axes.c2p(1, 0))
x_line.set_stroke(YELLOW, 3)
arrow = Vector(DOWN)
arrow.next_to(s_part, DOWN, SMALL_BUFF)
value = DecimalNumber(0, num_decimal_places=4)
value.set_color(YELLOW)
value.next_to(arrow, DOWN)
self.add(axes)
self.add(p_label)
self.play(
s_part.next_to, x_line.get_start(), UR, SMALL_BUFF,
GrowArrow(arrow),
FadeInFromPoint(value, s_part.get_center()),
)
s_part.tracked = x_line
value.tracked = x_line
value.x_axis = axes.x_axis
self.play(
ShowCreation(x_line),
UpdateFromFunc(
s_part,
lambda m: m.next_to(m.tracked.get_end(), UR, SMALL_BUFF)
),
UpdateFromFunc(
value,
lambda m: m.set_value(
m.x_axis.p2n(m.tracked.get_end())
)
),
run_time=3,
)
self.wait()
self.play(
FadeOut(arrow),
FadeOut(value),
)
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self.p_label = p_label
self.s_part = s_part
self.value = value
self.x_line = x_line
self.axes = axes
def show_arrows(self):
axes = self.axes
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arrows = VGroup()
arrow_template = Vector(DOWN)
arrow_template.lock_triangulation()
def get_arrow(s, denom):
arrow = arrow_template.copy()
arrow.set_height(4 / denom)
arrow.move_to(axes.c2p(s, 0), DOWN)
arrow.set_color(interpolate_color(
GREY_A, GREY_C, random.random()
))
return arrow
for k in range(2, 50):
for n in range(1, k):
if np.gcd(n, k) != 1:
continue
s = n / k
arrows.add(get_arrow(s, k))
for k in range(50, 1000):
arrows.add(get_arrow(1 / k, k))
arrows.add(get_arrow(1 - 1 / k, k))
kw = {
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"lag_ratio": 0.5,
"run_time": 5,
"rate_func": lambda t: t**4,
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}
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arrows.save_state()
for arrow in arrows:
arrow.stretch(0, 0)
arrow.set_stroke(width=0)
arrow.set_opacity(0)
self.play(Restore(arrows, **kw))
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self.play(LaggedStartMap(
ApplyMethod, arrows,
lambda m: (m.scale, 0, {"about_edge": DOWN}),
**kw
))
self.remove(arrows)
self.wait()
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def show_discrete_probabilities(self):
axes = self.axes
x_lines = VGroup()
dx = 0.01
for x in np.arange(0, 1, dx):
line = Line(
axes.c2p(x, 0),
axes.c2p(x + dx, 0),
)
line.set_stroke(BLUE, 3)
line.generate_target()
line.target.rotate(
90 * DEGREES,
about_point=line.get_start()
)
x_lines.add(line)
self.add(x_lines)
self.play(
FadeOut(self.x_line),
LaggedStartMap(
MoveToTarget, x_lines,
)
)
label = Integer(0)
label.set_height(0.5)
label.next_to(self.p_label[1], DOWN, LARGE_BUFF)
unit = TexMobject("\\%")
unit.match_height(label)
fix_percent(unit.family_members_with_points()[0])
always(unit.next_to, label, RIGHT, SMALL_BUFF)
arrow = Arrow()
arrow.max_stroke_width_to_length_ratio = 1
arrow.axes = axes
arrow.label = label
arrow.add_updater(lambda m: m.put_start_and_end_on(
m.label.get_bottom() + MED_SMALL_BUFF * DOWN,
m.axes.c2p(0.01 * m.label.get_value(), 0.03),
))
self.add(label, unit, arrow)
self.play(
ChangeDecimalToValue(label, 99),
run_time=5,
)
self.wait()
self.play(*map(FadeOut, [label, unit, arrow]))
# Show prior label
p_label = self.p_label
given_data = p_label[2:4]
prior_label = TexMobject("P(s)", tex_to_color_map={"s": YELLOW})
prior_label.match_height(p_label)
prior_label.move_to(p_label, DOWN, LARGE_BUFF)
p_label.save_state()
self.play(
given_data.scale, 0.5,
given_data.set_opacity, 0.5,
given_data.to_corner, UR,
Transform(p_label[:2], prior_label[:2]),
Transform(p_label[-1], prior_label[-1]),
)
self.wait()
# Zoom in on the y-values
new_ticks = VGroup()
new_labels = VGroup()
dy = 0.01
for y in np.arange(dy, 5 * dy, dy):
height = get_norm(axes.c2p(0, dy) - axes.c2p(0, 0))
tick = axes.y_axis.get_tick(y, SMALL_BUFF)
label = DecimalNumber(y)
label.match_height(axes.y_axis.numbers[0])
always(label.next_to, tick, LEFT, SMALL_BUFF)
new_ticks.add(tick)
new_labels.add(label)
for num in axes.y_axis.numbers:
height = num.get_height()
always(num.set_height, height, stretch=True)
bars = VGroup()
dx = 0.01
origin = axes.c2p(0, 0)
for x in np.arange(0, 1, dx):
rect = Rectangle(
width=get_norm(axes.c2p(dx, 0) - origin),
height=get_norm(axes.c2p(0, dy) - origin),
)
rect.x = x
rect.set_stroke(BLUE, 1)
rect.set_fill(BLUE, 0.5)
rect.move_to(axes.c2p(x, 0), DL)
bars.add(rect)
stretch_group = VGroup(
axes.y_axis,
bars,
new_ticks,
x_lines,
)
x_lines.set_height(
bars.get_height(),
about_edge=DOWN,
stretch=True,
)
self.play(
stretch_group.stretch, 25, 1, {"about_point": axes.c2p(0, 0)},
VFadeIn(bars),
VFadeIn(new_ticks),
VFadeIn(new_labels),
VFadeOut(x_lines),
run_time=4,
)
highlighted_bars = bars.copy()
highlighted_bars.set_color(YELLOW)
self.play(
LaggedStartMap(
FadeIn, highlighted_bars,
lag_ratio=0.5,
rate_func=there_and_back,
),
ShowCreationThenFadeAround(new_labels[0]),
run_time=3,
)
self.remove(highlighted_bars)
# Nmae as prior
prior_name = TextMobject("Prior", " distribution")
prior_name.set_height(0.6)
prior_name.next_to(prior_label, DOWN, LARGE_BUFF)
self.play(FadeInFromDown(prior_name))
self.wait()
# Show alternate distribution
bars.save_state()
for a, b in [(5, 2), (1, 6)]:
dist = scipy.stats.beta(a, b)
for bar, saved in zip(bars, bars.saved_state):
bar.target = saved.copy()
height = get_norm(axes.c2p(0.1 * dist.pdf(bar.x)) - axes.c2p(0, 0))
bar.target.set_height(height, about_edge=DOWN, stretch=True)
self.play(LaggedStartMap(MoveToTarget, bars, lag_ratio=0.00))
self.wait()
self.play(Restore(bars))
self.wait()
uniform_name = TextMobject("Uniform")
uniform_name.match_height(prior_name)
uniform_name.move_to(prior_name, DL)
uniform_name.shift(RIGHT)
uniform_name.set_y(bars.get_top()[1] + MED_SMALL_BUFF, DOWN)
self.play(
prior_name[0].next_to, uniform_name, RIGHT, MED_SMALL_BUFF, DOWN,
FadeOutAndShift(prior_name[1], RIGHT),
FadeInFrom(uniform_name, LEFT)
)
self.wait()
self.bars = bars
self.uniform_label = VGroup(uniform_name, prior_name[0])
def show_bayes_formula(self):
uniform_label = self.uniform_label
p_label = self.p_label
bars = self.bars
prior_label = VGroup(
p_label[0].deepcopy(),
p_label[1].deepcopy(),
p_label[4].deepcopy(),
)
eq = TexMobject("=")
likelihood_label = TexMobject(
"P(", "\\text{data}", "|", "s", ")",
)
likelihood_label.set_color_by_tex("data", GREEN)
likelihood_label.set_color_by_tex("s", YELLOW)
over = Line(LEFT, RIGHT)
p_data_label = TextMobject("P(", "\\text{data}", ")")
p_data_label.set_color_by_tex("data", GREEN)
for mob in [eq, likelihood_label, over, p_data_label]:
mob.scale(1.5)
mob.set_opacity(0.1)
eq.move_to(prior_label, LEFT)
over.set_width(
prior_label.get_width() +
likelihood_label.get_width() +
MED_SMALL_BUFF
)
over.next_to(eq, RIGHT, MED_SMALL_BUFF)
p_data_label.next_to(over, DOWN, MED_SMALL_BUFF)
likelihood_label.next_to(over, UP, MED_SMALL_BUFF, RIGHT)
self.play(
p_label.restore,
p_label.next_to, eq, LEFT, MED_SMALL_BUFF,
prior_label.next_to, over, UP, MED_SMALL_BUFF, LEFT,
FadeIn(eq),
FadeIn(likelihood_label),
FadeIn(over),
FadeIn(p_data_label),
FadeOut(uniform_label),
)
# Show new distribution
post_bars = bars.copy()
total_prob = 0
for bar, p in zip(post_bars, np.arange(0, 1, 0.01)):
prob = scipy.stats.binom(50, p).pmf(48)
bar.stretch(prob, 1, about_edge=DOWN)
total_prob += 0.01 * prob
post_bars.stretch(1 / total_prob, 1, about_edge=DOWN)
post_bars.stretch(0.25, 1, about_edge=DOWN) # Lie to fit on screen...
post_bars.set_color(MAROON_D)
post_bars.set_fill(opacity=0.8)
brace = Brace(p_label, DOWN)
post_word = brace.get_text("Posterior")
post_word.scale(1.25, about_edge=UP)
post_word.set_color(MAROON_D)
self.play(
ReplacementTransform(
bars.copy().set_opacity(0),
post_bars,
),
GrowFromCenter(brace),
FadeInFrom(post_word, 0.25 * UP)
)
self.wait()
self.play(
eq.set_opacity, 1,
likelihood_label.set_opacity, 1,
)
self.wait()
data = get_check_count_label(48, 2)
data.scale(1.5)
data.next_to(likelihood_label, DOWN, buff=2, aligned_edge=LEFT)
data_arrow = Arrow(
likelihood_label[1].get_bottom(),
data.get_top()
)
data_arrow.set_color(GREEN)
self.play(
GrowArrow(data_arrow),
GrowFromPoint(data, data_arrow.get_start()),
)
self.wait()
self.play(FadeOut(data_arrow))
self.play(
over.set_opacity, 1,
p_data_label.set_opacity, 1,
)
self.wait()
self.play(
FadeOut(brace),
FadeOut(post_word),
FadeOut(post_bars),
FadeOut(data),
p_label.set_opacity, 0.1,
eq.set_opacity, 0.1,
likelihood_label.set_opacity, 0.1,
over.set_opacity, 0.1,
p_data_label.set_opacity, 0.1,
)
self.bayes = VGroup(
p_label, eq,
prior_label, likelihood_label,
over, p_data_label
)
self.data = data
def parallel_universes(self):
bars = self.bars
cols = VGroup()
squares = VGroup()
sample_colors = color_gradient(
[GREEN_C, GREEN_D, GREEN_E],
100
)
for bar in bars:
n_rows = 12
col = VGroup()
for x in range(n_rows):
square = Rectangle(
width=bar.get_width(),
height=bar.get_height() / n_rows,
)
square.set_stroke(width=0)
square.set_fill(opacity=1)
square.set_color(random.choice(sample_colors))
col.add(square)
squares.add(square)
col.arrange(DOWN, buff=0)
col.move_to(bar)
cols.add(col)
squares.shuffle()
self.play(
LaggedStartMap(
VFadeInThenOut, squares,
lag_ratio=0.005,
run_time=3
)
)
self.remove(squares)
squares.set_opacity(1)
self.wait()
example_col = cols[95]
self.play(
bars.set_opacity, 0.25,
FadeIn(example_col, lag_ratio=0.1),
)
self.wait()
dist = scipy.stats.binom(50, 0.95)
for x in range(12):
square = random.choice(example_col).copy()
square.set_fill(opacity=0)
square.set_stroke(YELLOW, 2)
self.add(square)
nc = dist.ppf(random.random())
data = get_check_count_label(nc, 50 - nc)
data.next_to(example_col, UP)
self.add(square, data)
self.wait(0.5)
self.remove(square, data)
self.wait()
self.data.set_opacity(1)
self.play(
FadeIn(self.data),
FadeOut(example_col),
self.bayes[3].set_opacity, 1,
)
self.wait()
def update_from_data(self):
bars = self.bars
data = self.data
bayes = self.bayes
new_bars = bars.copy()
new_bars.set_stroke(opacity=1)
new_bars.set_fill(opacity=0.8)
for bar, p in zip(new_bars, np.arange(0, 1, 0.01)):
dist = scipy.stats.binom(50, p)
scalar = dist.pmf(48)
bar.stretch(scalar, 1, about_edge=DOWN)
self.play(
ReplacementTransform(
bars.copy().set_opacity(0),
new_bars
),
bars.set_fill, {"opacity": 0.1},
bars.set_stroke, {"opacity": 0.1},
run_time=2,
)
# Show example bar
bar95 = VGroup(
bars[95].copy(),
new_bars[95].copy()
)
bar95.save_state()
bar95.generate_target()
bar95.target.scale(2)
bar95.target.next_to(bar95, UP, LARGE_BUFF)
bar95.target.set_stroke(BLUE, 3)
ex_label = TexMobject("s", "=", "0.95")
ex_label.set_color(YELLOW)
ex_label.next_to(bar95.target, DOWN, submobject_to_align=ex_label[-1])
highlight = SurroundingRectangle(bar95, buff=0)
highlight.set_stroke(YELLOW, 2)
self.play(FadeIn(highlight))
self.play(
MoveToTarget(bar95),
FadeInFromDown(ex_label),
data.shift, LEFT,
)
self.wait()
side_brace = Brace(bar95[1], RIGHT, buff=SMALL_BUFF)
side_label = side_brace.get_text("0.26", buff=SMALL_BUFF)
self.play(
GrowFromCenter(side_brace),
FadeIn(side_label)
)
self.wait()
self.play(
FadeOut(side_brace),
FadeOut(side_label),
FadeOut(ex_label),
)
self.play(
bar95.restore,
bar95.set_opacity, 0,
)
for bar in bars[94:80:-1]:
highlight.move_to(bar)
self.wait(0.5)
self.play(FadeOut(highlight))
self.wait()
# Emphasize formula terms
tops = VGroup()
for bar, new_bar in zip(bars, new_bars):
top = Line(bar.get_corner(UL), bar.get_corner(UR))
top.set_stroke(YELLOW, 2)
top.generate_target()
top.target.move_to(new_bar, UP)
tops.add(top)
rect = SurroundingRectangle(bayes[2])
rect.set_stroke(YELLOW, 1)
rect.target = SurroundingRectangle(bayes[3])
rect.target.match_style(rect)
self.play(
ShowCreation(rect),
ShowCreation(tops),
)
self.wait()
self.play(
LaggedStartMap(
MoveToTarget, tops,
run_time=2,
lag_ratio=0.02,
),
MoveToTarget(rect),
)
self.play(FadeOut(tops))
self.wait()
# Show alternate priors
axes = self.axes
bar_groups = VGroup()
for bar, new_bar in zip(bars, new_bars):
bar_groups.add(VGroup(bar, new_bar))
bar_groups.save_state()
for a, b in [(5, 2), (7, 1)]:
dist = scipy.stats.beta(a, b)
for bar, saved in zip(bar_groups, bar_groups.saved_state):
bar.target = saved.copy()
height = get_norm(axes.c2p(0.1 * dist.pdf(bar[0].x)) - axes.c2p(0, 0))
height = max(height, 1e-6)
bar.target.set_height(height, about_edge=DOWN, stretch=True)
self.play(LaggedStartMap(MoveToTarget, bar_groups, lag_ratio=0))
self.wait()
self.play(Restore(bar_groups))
self.wait()
# Rescale
ex_p_label = TexMobject(
"P(s = 0.95 | 00000000) = ",
tex_to_color_map={
"s = 0.95": YELLOW,
"00000000": WHITE,
}
)
ex_p_label.scale(1.5)
ex_p_label.next_to(bars, UP, LARGE_BUFF)
ex_p_label.align_to(bayes, LEFT)
template = ex_p_label.get_part_by_tex("00000000")
template.set_opacity(0)
highlight = SurroundingRectangle(new_bars[95], buff=0)
highlight.set_stroke(YELLOW, 1)
self.remove(data)
self.play(
FadeIn(ex_p_label),
VFadeOut(data[0]),
data[1:].move_to, template,
FadeIn(highlight)
)
self.wait()
numer = new_bars[95].copy()
numer.set_stroke(YELLOW, 1)
denom = new_bars[80:].copy()
h_line = Line(LEFT, RIGHT)
h_line.set_width(3)
h_line.set_stroke(width=2)
h_line.next_to(ex_p_label, RIGHT)
self.play(
numer.next_to, h_line, UP,
denom.next_to, h_line, DOWN,
ShowCreation(h_line),
)
self.wait()
self.play(
denom.space_out_submobjects,
rate_func=there_and_back
)
self.play(
bayes[4].set_opacity, 1,
bayes[5].set_opacity, 1,
FadeOut(rect),
)
self.wait()
# Rescale
self.play(
FadeOut(highlight),
FadeOut(ex_p_label),
FadeOut(data),
FadeOut(h_line),
FadeOut(numer),
FadeOut(denom),
bayes.set_opacity, 1,
)
new_bars.unlock_shader_data()
self.remove(new_bars, *new_bars)
self.play(
new_bars.set_height, 5, {"about_edge": DOWN, "stretch": True},
new_bars.set_color, MAROON_D,
)
self.wait()
class UniverseOf95Percent(WhatsTheModel):
CONFIG = {"s": 0.95}
def construct(self):
self.introduce_buyer_and_seller()
for m, v in [(self.seller, RIGHT), (self.buyer, LEFT)]:
m.shift(v)
m.label.shift(v)
pis = VGroup(self.seller, self.buyer)
label = get_prob_positive_experience_label(True, True)
label[-1].set_value(self.s)
label.set_height(1)
label.next_to(pis, UP, LARGE_BUFF)
self.add(label)
for x in range(4):
self.play(*self.experience_animations(
self.seller, self.buyer, arc=30 * DEGREES, p=self.s
))
self.embed()
class UniverseOf50Percent(UniverseOf95Percent):
CONFIG = {"s": 0.5}
class OpenAndCloseAsideOnPdfs(Scene):
def construct(self):
labels = VGroup(
TextMobject("$\\langle$", "Aside on", " pdfs", "$\\rangle$"),
TextMobject("$\\langle$/", "Aside on", " pdfs", "$\\rangle$"),
)
labels.set_width(FRAME_WIDTH / 2)
for label in labels:
label.set_color_by_tex("pdfs", YELLOW)
self.play(FadeInFromDown(labels[0]))
self.wait()
self.play(Transform(*labels))
self.wait()
class TryAssigningProbabilitiesToSpecificValues(Scene):
def construct(self):
# To get "P(s = 95.9999%) ="" type labels
def get_p_label(value):
result = TexMobject(
"P(", "{s}", "=", value, "\\%", ")",
)
fix_percent(result.get_part_by_tex("\\%")[0])
result.set_color_by_tex("{s}", YELLOW)
return result
labels = VGroup(
get_p_label("95.0000000"),
get_p_label("94.9999999"),
get_p_label("94.9314159"),
get_p_label("94.9271828"),
get_p_label("94.9466920"),
get_p_label("94.9161803"),
)
labels.arrange(DOWN, buff=0.35, aligned_edge=LEFT)
q_marks = VGroup()
gt_zero = VGroup()
eq_zero = VGroup()
for label in labels:
qm = TexMobject("=", "\\,???")
qm.next_to(label, RIGHT)
qm[1].set_color(TEAL)
q_marks.add(qm)
gt = TexMobject("> 0")
gt.next_to(label, RIGHT)
gt_zero.add(gt)
eqz = TexMobject("= 0")
eqz.next_to(label, RIGHT)
eq_zero.add(eqz)
v_dots = TexMobject("\\vdots")
v_dots.next_to(q_marks[-1][0], DOWN, MED_LARGE_BUFF)
# Animations
self.play(FadeInFromDown(labels[0]))
self.play(FadeInFrom(q_marks[0], LEFT))
self.wait()
self.play(*[
TransformFromCopy(m1, m2)
for m1, m2 in [
(q_marks[0], q_marks[1]),
(labels[0][:3], labels[1][:3]),
(labels[0][5], labels[1][5]),
]
])
self.play(ShowIncreasingSubsets(
labels[1][3],
run_time=3,
int_func=np.ceil,
rate_func=linear,
))
self.add(labels[1])
self.wait()
self.play(
LaggedStartMap(
FadeInFrom, labels[2:],
lambda m: (m, UP),
),
LaggedStartMap(
FadeInFrom, q_marks[2:],
lambda m: (m, UP),
),
Write(v_dots, rate_func=squish_rate_func(smooth, 0.5, 1))
)
self.add(labels, q_marks)
self.wait()
q_marks.unlock_triangulation()
self.play(
ReplacementTransform(q_marks, gt_zero, lag_ratio=0.05),
run_time=2,
)
self.wait()
# Show sum
group = VGroup(labels, gt_zero, v_dots)
sum_label = TexMobject(
"\\sum_{s}", "P(", "{s}", ")", "=",
tex_to_color_map={"{s}": YELLOW},
)
# sum_label.set_color_by_tex("{s}", YELLOW)
sum_label[0].set_color(WHITE)
sum_label.scale(1.75)
sum_label.next_to(ORIGIN, RIGHT, buff=1)
self.play(group.next_to, ORIGIN, LEFT)
self.play(Write(sum_label))
infty = TexMobject("\\infty")
zero = TexMobject("0")
for mob in [infty, zero]:
mob.scale(2)
mob.next_to(sum_label[-1], RIGHT)
zero.set_color(RED)
self.play(Write(infty))
self.wait()
# If equal to zero
eq_zero.move_to(gt_zero)
eq_zero.set_color(RED)
gt_zero.unlock_triangulation()
self.play(
ReplacementTransform(gt_zero, eq_zero),
lag_ratio=0.05,
run_time=2,
path_arc=30 * DEGREES,
)
self.wait()
self.play(
FadeInFrom(zero, DOWN),
FadeOutAndShift(infty, UP),
)
self.wait()
class ShowLimitToPdf(Scene):
def construct(self):
# Init
axes = self.get_axes()
dist = scipy.stats.beta(4, 2)
bars = self.get_bars(axes, dist, 0.05)
axis_prob_label = TextMobject("Probability")
axis_prob_label.next_to(axes.y_axis, UP)
axis_prob_label.to_edge(LEFT)
self.add(axes)
self.add(axis_prob_label)
# From individual to ranges
kw = {"tex_to_color_map": {"s": YELLOW}}
eq_label = TexMobject("P(s = 0.8)", **kw)
ineq_label = TexMobject("P(0.8 < s < 0.85)", **kw)
arrows = VGroup(Vector(DOWN), Vector(DOWN))
for arrow, x in zip(arrows, [0.8, 0.85]):
arrow.move_to(axes.c2p(x, 0), DOWN)
brace = Brace(
Line(arrows[0].get_start(), arrows[1].get_start()),
UP, buff=SMALL_BUFF
)
eq_label.next_to(arrows[0], UP)
ineq_label.next_to(brace, UP)
self.play(
FadeInFrom(eq_label, 0.2 * DOWN),
GrowArrow(arrows[0]),
)
self.wait()
vect = eq_label.get_center() - ineq_label.get_center()
self.play(
FadeOutAndShift(eq_label, -vect),
FadeInFrom(ineq_label, vect),
TransformFromCopy(*arrows),
GrowFromPoint(brace, brace.get_left()),
)
self.wait()
arrows[0].generate_target()
arrows[0].target.next_to(bars[16], UP, SMALL_BUFF)
for bar in bars:
bar.save_state()
bar.stretch(0, 1, about_edge=DOWN)
kw = {
"run_time": 2,
"rate_func": squish_rate_func(smooth, 0.3, 0.9),
}
self.play(
MoveToTarget(arrows[0], **kw),
ApplyMethod(ineq_label.next_to, arrows[0].target, UP, **kw),
FadeOut(arrows[1]),
FadeOut(brace),
LaggedStartMap(Restore, bars, run_time=2, lag_ratio=0.025),
)
self.wait()
# Focus on area, not height
lines = VGroup()
new_bars = VGroup()
for bar in bars:
line = Line(
bar.get_corner(DL),
bar.get_corner(DR),
)
line.set_stroke(YELLOW, 0)
line.generate_target()
line.target.set_stroke(YELLOW, 3)
line.target.move_to(bar.get_top())
lines.add(line)
new_bar = bar.copy()
new_bar.match_style(line)
new_bar.set_fill(YELLOW, 0.5)
new_bar.generate_target()
new_bar.stretch(0, 1, about_edge=UP)
new_bars.add(new_bar)
prob_label = TextMobject(
"Height",
"$\\rightarrow$",
"Probability",
)
prob_label.space_out_submobjects(1.1)
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prob_label.next_to(bars[10], UL, LARGE_BUFF)
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height_word = prob_label[0]
height_cross = Cross(height_word)
area_word = TextMobject("Area")
area_word.move_to(height_word, UR)
area_word.set_color(YELLOW)
self.play(
LaggedStartMap(
MoveToTarget, lines,
lag_ratio=0.01,
),
FadeInFromDown(prob_label),
)
self.add(height_word)
self.play(
ShowCreation(height_cross),
FadeOutAndShift(axis_prob_label, LEFT)
)
self.wait()
self.play(
FadeOutAndShift(height_word, UP),
FadeOutAndShift(height_cross, UP),
FadeInFromDown(area_word),
)
self.play(
FadeOut(lines),
LaggedStartMap(
MoveToTarget, new_bars,
lag_ratio=0.01,
)
)
self.play(
FadeOut(new_bars),
area_word.set_color, BLUE,
)
prob_label = VGroup(area_word, *prob_label[1:])
self.add(prob_label)
self.embed()
def get_axes(self):
axes = Axes(
x_min=0,
x_max=1,
x_axis_config={
"tick_frequency": 0.05,
"unit_size": 12,
"include_tip": False,
},
y_min=0,
y_max=4,
y_axis_config={
"tick_frequency": 1,
"unit_size": 1.25,
"include_tip": False,
}
)
axes.center()
s_label = TexMobject("s")
s_label.set_color(YELLOW)
s_label.next_to(axes.x_axis, RIGHT)
axes.x_axis.add(s_label)
axes.x_axis.s_label = s_label
axes.x_axis.add_numbers(
*np.arange(0.2, 1.2, 0.2),
number_config={"num_decimal_places": 1}
)
return axes
def get_bars(self, axes, dist, step_size):
bars = VGroup()
for x in np.arange(0, 1, step_size):
bar = Rectangle()
bar.set_stroke(BLUE, 2)
bar.set_fill(BLUE, 0.5)
h_line = Line(
axes.c2p(x, 0),
axes.c2p(x + step_size, 0),
)
v_line = Line(
axes.c2p(0, 0),
axes.c2p(0, dist.pdf(x)),
)
bar.match_width(h_line, stretch=True)
bar.match_height(v_line, stretch=True)
bar.move_to(h_line, DOWN)
bars.add(bar)
return bars