files with gifs

1 files changed, 82 insertions, 0 deletions

diff --git a/FSF-2020/calculus-of-several-variables/div-curl-grad-and-all-that/Curl and Div/DivCurl_file9_formal-def.py b/FSF-2020/calculus-of-several-variables/div-curl-grad-and-all-that/Curl and Div/DivCurl_file9_formal-def.py
new file mode 100644
index 0000000..ecafca4
--- /dev/null
+++ b/FSF-2020/calculus-of-several-variables/div-curl-grad-and-all-that/Curl and Div/DivCurl_file9_formal-def.py
@@ -0,0 +1,82 @@
+from manimlib.imports import *
+import numpy as np
+
+
+
+def func(coordinate):
+	x,y = coordinate[:2]
+	return np.array([
+			1.9*np.cos(x+2*y),
+			1.5*np.sin(x-2*y),
+			0
+	])
+
+def coord(x,y,z=0):
+	return np.array([x,y,z])
+
+class Instrument(Scene):
+	CONFIG = {
+		"x_coords": ([1, 2.2, 3.9, 3, -0, -0.2, 1]),
+		"y_coords": ([1.5, 1, -0.5, -2.0, -1.4, 0.5, 1.5]),
+	}
+
+	def setup(self):
+		self.tuples = list(zip(self.x_coords,self.y_coords))
+		dots = self.get_all_mobs()
+
+	def get_dots(self, coords):
+		dots = VGroup(*[Dot(coord(x,y)) for x,y in coords])
+		return dots
+	
+	def get_all_mobs(self):
+		dots = self.get_dots(self.tuples)
+		return dots
+
+
+class Curl_one(MovingCameraScene, Instrument):
+	def setup(self):
+		MovingCameraScene.setup(self)
+		Instrument.setup(self)
+
+
+	def construct(self):
+		vec = VectorField(func)
+
+
+		frame_one = Circle(radius = 0.5).move_to(np.array([4, 2, 0]))
+		dot = Dot(frame_one.get_center()).scale(0.5)
+		surface = VMobject()
+		surface.set_points_smoothly([*[coord(x,y) for x,y in self.tuples]])
+		surface.move_to(dot.get_center()).set_stroke(width = 0.5)
+		
+		label = TexMobject(r"A").scale(0.5).next_to(dot, LEFT+UP, buff = SMALL_BUFF)
+		#self.add(frame_one)
+		self.camera_frame.save_state()
+		self.play(
+			self.camera_frame.set_width,frame_one.get_width()*7.0,
+			self.camera_frame.move_to,frame_one)
+
+
+	
+
+		self.add(vec, dot, label)
+		lines = StreamLines(
+			func,
+			virtual_time=7,
+			min_magnitude=0,
+			max_magnitude=8,
+		)
+		lines1 = AnimatedStreamLines(
+			lines,
+			line_anim_class=ShowPassingFlashWithThinningStrokeWidth
+		)
+
+		self.add(lines1)
+		self.wait(3)
+		self.play(Restore(self.camera_frame))
+		self.wait(2)
+		self.add(surface)
+		self.wait(3)
+		self.play(ApplyMethod(surface.scale, 0.01), run_time = 2)
+		self.remove(surface)
+		self.wait(2)