Finished pi day

This commit is contained in:
Grant Sanderson 2018-03-14 14:52:33 -07:00
parent d6f8d5b0c4
commit 9ccc9fa8b4
3 changed files with 499 additions and 15 deletions

View file

@ -32,6 +32,7 @@ from camera import *
from mobject.svg_mobject import *
from mobject.tex_mobject import *
from topics.graph_scene import *
from topics.common_scenes import *
RESOURCE_DIR = os.path.join(MEDIA_DIR, "3b1b_videos", "π Day 2018", "images")
def get_image(name):
@ -415,6 +416,488 @@ class HeroAndVillain(Scene):
self.remove(bad_euler_pixelated)
self.wait(2)
class AnalysisQuote(Scene):
def construct(self):
analysis = get_image("Analysis_page_showing_pi")
analysis.scale_to_fit_height(2*SPACE_HEIGHT)
analysis.to_edge(LEFT, buff = 0)
text = TextMobject(
"``\\dots set the radius of",
"the circle\\dots to be = 1, \\dots \\\\",
"through approximations the",
"semicircumference \\\\", "of said circle",
"has been found to be", "$= 3.14159\\dots$,\\\\",
"for which number, for the sake of",
"brevity, \\\\ I will write", "$\pi$\\dots''",
alignment = ''
)
pi_formula = TexMobject(
"\\pi", "=", "{ \\text{semicircumference}", "\\over", "\\text{radius}}"
)
text.scale_to_fit_width(SPACE_WIDTH)
text.next_to(analysis, RIGHT, LARGE_BUFF)
text.to_edge(UP)
HIGHLIGHT_COLOR= GREEN
for mob in text, pi_formula:
mob.highlight_by_tex_to_color_map({
"semicircumference" : HIGHLIGHT_COLOR,
"3.14" : HIGHLIGHT_COLOR,
"\pi" : HIGHLIGHT_COLOR
})
terms, generate_anims1, generate_anims2 = get_circle_drawing_terms(
radius = 1,
positioning_func = lambda circ : circ.next_to(text, DOWN, LARGE_BUFF)
)
terms[0].highlight(HIGHLIGHT_COLOR)
terms[-1].highlight(HIGHLIGHT_COLOR)
pi_formula.next_to(terms, DOWN, buff = 0)
pi_formula.align_to(text, alignment_vect = RIGHT)
pi_formula[0].scale(2, about_edge = RIGHT)
self.add(analysis)
self.play(*generate_anims2(), rate_func = lambda t : 0.5*smooth(t))
self.play(LaggedStart(FadeIn,text), run_time = 5)
self.play(FadeIn(pi_formula))
self.wait()
class QuarterTurn(Scene):
def construct(self):
terms, generate_anims1, generate_anims2 = get_circle_drawing_terms(
radius = 2,
positioning_func = lambda circ : circ.move_to(4*RIGHT)
)
circle, radius, one, decimal = terms
circle_ghost = circle.copy().set_stroke(YELLOW_E, 1)
radius_ghost = radius.copy().set_stroke(WHITE, 1)
self.add(circle_ghost, radius_ghost)
self.play(
*generate_anims2(),
rate_func = lambda t : 0.25*smooth(t)
)
self.wait()
pi_halves = TexMobject("\\pi", "/2")
pi_halves[0].highlight(RED)
tau_fourths = TexMobject("\\tau", "/4")
tau_fourths[0].highlight(GREEN)
for mob in pi_halves, tau_fourths:
mob.next_to(decimal, UP)
self.play(FadeInFromDown(pi_halves))
self.wait()
self.play(
pi_halves.shift, 0.75*UP,
FadeInFromDown(tau_fourths)
)
self.wait()
class UsingTheta(Scene):
def construct(self):
plane = NumberPlane(x_unit_size = 3, y_unit_size = 3)
# plane.main_lines.fade(0.5)
# plane.secondary_lines.fade(0.5)
plane.fade(0.5)
self.add(plane)
circle = Circle(radius = 3)
circle.set_stroke(YELLOW, 2)
self.add(circle)
radius = Line(ORIGIN, circle.get_right())
arc = Arc(radius = 0.5, angle = TAU, num_anchors = 200)
arc.highlight(GREEN)
start_arc = arc.copy()
theta = TexMobject("\\theta", "=")
theta[0].match_color(arc)
theta.add_background_rectangle()
update_theta = ContinualUpdateFromFunc(
theta, lambda m : m.shift(
rotate_vector(0.9*RIGHT, radius.get_angle()/2) \
- m[1][0].get_center()
)
)
angle = Integer(0, unit = "^\\circ")
update_angle = ContinualChangingDecimal(
angle, lambda a : radius.get_angle()*(360/TAU),
position_update_func = lambda a : a.next_to(theta, RIGHT, SMALL_BUFF)
)
self.add(update_theta, update_angle)
last_frac = 0
for frac in 1./4, 1./12, 3./8, 1./6, 5./6:
self.play(
Rotate(radius, angle = (frac-last_frac)*TAU, about_point = ORIGIN),
UpdateFromAlphaFunc(
arc,
lambda m, a : m.pointwise_become_partial(
start_arc, 0, interpolate(last_frac, frac, a)
)
),
run_time = 3
)
last_frac = frac
self.wait()
class ThingsNamedAfterEuler(Scene):
def construct(self):
group = VGroup(*map(TextMobject, [
"Euler's formula (Complex analysis)",
"Euler's formula (Graph theory)",
"Euler's formula (Mechanical engineering)",
"Euler's formula (Analytical number theory)",
"Euler's formula (Continued fractions)",
"Euler-Lagrance equations (mechanics)",
"Euler number (topology)",
"Euler equations (fluid dynamics)",
"Euler angles (rigid-body mechanics)",
"Euler totient function (number theory)",
]))
group.arrange_submobjects(DOWN, aligned_edge = LEFT)
group.scale_to_fit_height(2*SPACE_HEIGHT - 1)
self.play(LaggedStart(FadeIn, group, lag_ratio = 0.2, run_time = 12))
self.wait()
class EulerThinking(Scene):
def construct(self):
image = get_image("Leonhard_Euler_by_Handmann")
image.scale_to_fit_height(4)
image.to_edge(DOWN)
image.shift(4*LEFT)
bubble = ThoughtBubble(height = 4.5)
bubble.next_to(image, RIGHT)
bubble.to_edge(UP, buff = SMALL_BUFF)
bubble.shift(0.8*LEFT)
bubble.set_fill(BLACK, 0.3)
pi_vs_tau = TextMobject(
"Should $\\pi$ represent \\\\", "3.1415...",
"or", "6.2831...", "?"
)
pi_vs_tau.highlight_by_tex_to_color_map({
"3.14" : GREEN,
"6.28" : RED,
})
pi_vs_tau.move_to(bubble.get_bubble_center())
question = TexMobject(
"\\frac{1}{1} + \\frac{1}{4} + \\frac{1}{9} + \\frac{1}{16} + \\cdots = ",
"\\;???"
)
question[0].gradient_highlight(BLUE_C, BLUE_B)
question.move_to(bubble.get_bubble_center())
question.shift(2*SMALL_BUFF*UP)
cross = Cross(pi_vs_tau)
cross.set_stroke(RED, 8)
self.add(image)
self.play(
ShowCreation(bubble),
Write(pi_vs_tau)
)
self.play(ShowCreation(cross))
self.wait()
self.play(
FadeOut(VGroup(pi_vs_tau, cross)),
FadeIn(question),
)
self.wait()
class WhatIsRight(PiCreatureScene):
CONFIG = {
"default_pi_creature_kwargs" : {
"color" : BLUE_D,
"filp_at_start" : False,
},
"default_pi_creature_start_corner" : DOWN,
}
def construct(self):
randy = self.pi_creature
randy.scale(0.75, about_edge = DOWN)
title = TextMobject("Which is ``right''?")
title.scale(1.5)
title.to_edge(UP)
self.add(title)
sum_over_N_converges = TexMobject("1+2+3+\\cdots = -\\frac{1}{12}")
sum_over_N_diverges = TexMobject("1+2+3+\\cdots \\text{ Diverges}")
literal_derivative = TexMobject(
"f'(x) = \\frac{f(x+dx) - f(x)}{dx}"
)
limit_derivative = TexMobject(
"f'(x) = \\lim_{h \\to 0}\\frac{f(x+h) - f(x)}{h}"
)
divide_by_zero_definable = TexMobject(
"\\frac{1}{0}", "\\text{ has meaning}"
)
divide_by_zero_undefinable = TexMobject(
"\\frac{1}{0}", "\\text{ is undefined}"
)
left_mobs = VGroup(
sum_over_N_converges, literal_derivative,
divide_by_zero_definable
)
right_mobs = VGroup(
sum_over_N_diverges, limit_derivative,
divide_by_zero_undefinable
)
for mob in left_mobs:
mob.next_to(randy, UP)
mob.shift(3.5*LEFT)
for mob in right_mobs:
mob.next_to(randy, UP)
mob.shift(3.5*RIGHT)
left_mobs.gradient_highlight(YELLOW_C, YELLOW_D)
right_mobs.gradient_highlight(GREEN_C, GREEN_D)
self.play(randy.change, "pondering", title)
self.wait()
self.play(randy.change, "sassy", title)
self.wait()
last_terms = VGroup()
for left, right in zip(left_mobs, right_mobs)[:-1]:
right.align_to(left)
self.play(
randy.change, "raise_right_hand",
FadeInFromDown(left),
last_terms.shift, 1.75*UP
)
self.wait()
self.play(
randy.change, "raise_left_hand",
FadeInFromDown(right)
)
self.play(randy.change, "plain", right)
last_terms.add(left, right, title)
self.play(
randy.change, "shruggie",
FadeInFromDown(left_mobs[-1]),
FadeInFromDown(right_mobs[-1]),
last_terms.shift, 1.75*UP,
)
self.wait(4)
class AskPuzzle(TeacherStudentsScene):
def construct(self):
series = TexMobject(
"\\frac{1}{1} + \\frac{1}{4} + \\frac{1}{9} + \\cdots + " +\
"\\frac{1}{n^2} + \\cdots = ", "\\,???"
)
series[0].gradient_highlight(BLUE_C, BLUE_B)
series[1].highlight(YELLOW)
question = TextMobject(
"How should we think about\\\\",
"$\\displaystyle \\sum_{n=1}^\\infty \\frac{1}{n^s}$",
"for arbitrary $s$?"
)
question[1].highlight(BLUE)
question[0].shift(SMALL_BUFF*UP)
response = TextMobject(
"What do you mean by ",
"$\\displaystyle \\sum_{n = 1}^{\\infty}$",
"?"
)
response[1].highlight(BLUE)
self.teacher_says(series)
self.change_all_student_modes("pondering", look_at_arg = series)
self.wait(3)
self.play(
FadeOut(self.teacher.bubble),
self.teacher.change, "happy",
series.scale, 0.5,
series.to_corner, UP+LEFT,
PiCreatureSays(
self.students[0], question,
target_mode = "raise_left_hand"
)
)
self.change_student_modes(
None, "confused", "confused",
added_anims = [self.students[0].look_at, question]
)
self.wait(2)
self.students[0].bubble.content = VGroup()
self.play(
RemovePiCreatureBubble(self.students[0]),
question.scale, 0.5,
question.next_to, series, DOWN, MED_LARGE_BUFF, LEFT,
PiCreatureSays(self.teacher, response)
)
self.change_all_student_modes("erm")
self.wait(3)
class ChangeTopic(PiCreatureScene):
def construct(self):
pi, tau = self.pi_creatures
title = TextMobject("Happy $\\pi$ day!")
title.scale(1.5)
title.to_edge(UP, buff = MED_SMALL_BUFF)
self.add(title)
question = TextMobject(
"Have you ever seen why \\\\",
"$\\displaystyle \\frac{2}{1} \\cdot \\frac{2}{3} \\cdots"+ \
"\\frac{4}{3} \\cdot \\frac{4}{5} \\cdot" + \
"\\frac{6}{5} \\cdot \\frac{6}{7} \\cdots = \\frac{\\pi}{2}$", "?"
)
question[0].shift(MED_SMALL_BUFF*UP)
question[1].gradient_highlight(YELLOW, GREEN)
self.play(
PiCreatureSays(
tau, "We should \\emph{really} celebrate \\\\ on 6/28!",
target_mode = "angry",
),
pi.change, "guilty",
)
self.wait(2)
self.play(
PiCreatureSays(pi, question),
RemovePiCreatureBubble(
tau, target_mode = "pondering", look_at_arg = question,
)
)
self.play(pi.change, "pondering", question)
self.wait(4)
def create_pi_creatures(self):
tau = TauCreature(color = GREEN_E)
pi = Randolph().flip()
VGroup(pi, tau).scale(0.75)
tau.to_edge(DOWN).shift(3*LEFT)
pi.to_edge(DOWN).shift(3*RIGHT)
return pi, tau
class SpecialThanks(Scene):
def construct(self):
title = TextMobject("Special thanks to:")
title.to_edge(UP, LARGE_BUFF)
title.scale(1.5)
title.highlight(BLUE)
h_line = Line(LEFT, RIGHT).scale(4)
h_line.next_to(title, DOWN)
h_line.set_stroke(WHITE, 1)
people = VGroup(*map(TextMobject, [
"Ben Hambrecht",
"University Library Basel",
"Martin Mattmüller",
"Library of the Institut de France",
]))
people.arrange_submobjects(DOWN, aligned_edge = LEFT, buff = MED_LARGE_BUFF)
people.next_to(h_line, DOWN)
self.add(title, h_line, people)
class EndScene(PatreonEndScreen):
CONFIG = {
"camera_config" : {
"background_alpha" : 255,
}
}
def construct(self):
self.add_title()
title = self.title
basel_screen = ScreenRectangle(height = 2.35)
basel_screen.next_to(title, DOWN)
watch_basel = TextMobject(
"One such actual piece of math", "(quite pretty!)",
)
watch_basel[0].highlight(YELLOW)
watch_basel.next_to(basel_screen, DOWN, submobject_to_align = watch_basel[0])
self.add(watch_basel)
# self.add(basel_screen)
line = DashedLine(SPACE_WIDTH*LEFT, SPACE_WIDTH*RIGHT)
line.next_to(watch_basel, DOWN)
self.add(line)
plushie_square = Square(side_length = 2)
plushie_square.to_corner(DOWN+LEFT, buff = MED_LARGE_BUFF)
plushie_square.shift(UP)
plushie_words = TextMobject(
"Plushie pi \\\\ creatures \\\\ now available.",
alignment = ""
)
plushie_words.next_to(plushie_square, RIGHT)
self.add(plushie_words)
# self.add(plushie_square)
instagram_line = TextMobject(
"randy\\_the\\_pi"
)
instagram_logo = ImageMobject("instagram_logo")
instagram_logo.match_height(instagram_line)
instagram_logo.next_to(instagram_line, LEFT, SMALL_BUFF)
instagram = Group(instagram_logo, instagram_line)
instagram.next_to(line, DOWN)
instagram.shift(SPACE_WIDTH*RIGHT/2)
self.add(instagram)
pictures = Group(*[
ImageMobject("randy/randy_%s"%name)
for name in [
"science",
"cooking",
"in_a_can",
"sandwhich",
"lab",
"fractal",
"flowers",
"group",
"labcoat",
"tennis",
]
])
for i, picture in enumerate(pictures):
picture.scale_to_fit_height(2)
picture.next_to(instagram, DOWN, aligned_edge = RIGHT)
if i%3 != 0:
picture.next_to(last_picture, LEFT, buff = 0)
self.play(FadeIn(picture, run_time = 2))
last_picture = picture
class Thumbnail(Scene):
def construct(self):
pi, eq, num = formula = TexMobject(
"\\pi", "=", "6.283185\\dots"
)
formula.scale(2)
pi.scale(1.5, about_edge = RIGHT)
formula.set_stroke(BLUE, 1)
formula.scale_to_fit_width(2*SPACE_WIDTH - 2)
# formula.shift(0.5*RIGHT)
self.add(formula)
words = TextMobject("...according to Euler.")
words.scale(1.5)
words.next_to(formula, DOWN, MED_LARGE_BUFF)
self.add(words)

View file

@ -46,19 +46,19 @@ class PiCreature(SVGMobject):
def __init__(self, mode = "plain", **kwargs):
digest_config(self, kwargs)
self.parts_named = False
# try:
svg_file = os.path.join(
PI_CREATURE_DIR,
"%s_%s.svg"%(self.file_name_prefix, mode)
)
SVGMobject.__init__(self, file_name = svg_file, **kwargs)
# except:
# warnings.warn("No %s design with mode %s"%(self.file_name_prefix, mode))
# svg_file = os.path.join(
# FILE_DIR,
# "PiCreatures_plain.svg",
# )
# SVGMobject.__init__(self, file_name = svg_file, **kwargs)
try:
svg_file = os.path.join(
PI_CREATURE_DIR,
"%s_%s.svg"%(self.file_name_prefix, mode)
)
SVGMobject.__init__(self, file_name = svg_file, **kwargs)
except:
warnings.warn("No %s design with mode %s"%(self.file_name_prefix, mode))
svg_file = os.path.join(
FILE_DIR,
"PiCreatures_plain.svg",
)
SVGMobject.__init__(self, file_name = svg_file, **kwargs)
if self.flip_at_start:
self.flip()

View file

@ -3,7 +3,8 @@ from helpers import *
from scene.scene import Scene
from animation import Animation
from animation.simple_animations import Write, DrawBorderThenFill, LaggedStart
from animation.simple_animations import Write, DrawBorderThenFill
from animation.compositions import LaggedStart
from animation.transform import FadeIn, FadeOut, ApplyMethod
from mobject.vectorized_mobject import VGroup
from mobject.tex_mobject import TexMobject, TextMobject
@ -132,7 +133,7 @@ class PatreonEndScreen(PatreonThanks):
self.scroll_through_patrons()
def add_title(self):
title = TextMobject("Clicky Stuffs")
title = self.title = TextMobject("Clicky Stuffs")
title.scale(1.5)
title.to_edge(UP, buff = MED_SMALL_BUFF)