removed unnecessary stuff

assorted_scenes/pascal_triangle.py

@@ -1,13 +1,19 @@
 from manim import *
-import math
-import itertools
+import math, itertools, functools
 
 def int_binom(n: int, k: int) -> int:
     if (k < 0) or (k > n):
         return(0)
     else:
         return(math.factorial(n) // (math.factorial(k) * math.factorial(n-k)))    
 
+def centroid(*iterables):
+    sum = functools.reduce((lambda x,y: x + y), iterables)
+    return(sum / float(len(iterables)))
+
+def center_centroid(*iterables):
+    return(centroid(*map((lambda x : x.get_center()), iterables)))
+
 class VRow(VGroup):
     def __init__(self, *vmobjects, spacing = 1 * RIGHT, **kwargs):
         super().__init__(**kwargs)
@@ -37,8 +43,8 @@ def construct(self):
         # Build Pascal's Triangle:
         tex_wrap = (lambda x: MathTex(str(x)))
         tex_coeff = {i: {j: tex_wrap(int_binom(i, j)) for j in range(0, i + 1)} for i in range(1, 5)}
-        rows = [VRow(*tex_coeff[i].values(), spacing = 2 * RIGHT) for i in tex_coeff.keys()]
-        triangle = VRow(*rows, spacing = 2 * DOWN)        
+        rows = [VGroup(*tex_coeff[i].values()).arrange_submobjects(RIGHT, buff = 2) for i in tex_coeff.keys()]
+        triangle = VGroup(*rows).arrange_submobjects(DOWN, buff = 2)        
         for i in tex_coeff.keys():
             self.play(Write(tex_coeff[i][0]), Write(tex_coeff[i][i]))
         self.wait(1)
@@ -47,7 +53,7 @@ def construct(self):
             self.wait(1)
             self.play(FadeIn(add_rig), Write(tex_coeff[i][1]))
             for j in range(1, i - 1):
-                self.play(add_rig.animate.shift(2 * RIGHT))
+                self.play(add_rig.animate.shift(center_centroid(tex_coeff[i-1][j], tex_coeff[i-1][j+1]) - add_rig.submobjects[0].get_center()))
                 self.play(Write(tex_coeff[i][j + 1]))
             self.play(FadeOut(add_rig))
 
@@ -59,35 +65,6 @@ def build_addition_rig(self, left_el, right_el):
         add_rig = VGroup(*[plus, arrow])
         return(add_rig)
 
-class SumAnimationWithZeros(Scene):
-    def construct(self):
-        # Build Pascal's Triangle:
-        tex_wrap = (lambda x: MathTex(str(x)))
-        tex_coeff = [{j: tex_wrap(int_binom(i, j)) for j in range(-1, i + 2)} for i in range(0, 4)]
-        rows = [VRow(*tex_coeff[i].values(), spacing = 2 * RIGHT) for i in range(len(tex_coeff))]
-        triangle = VRow(*rows, spacing = 2 * DOWN)        
-
-        self.play(Write(tex_coeff[0][0]))
-        self.wait(1)
-        for i in range(1, len(rows)):
-            add_rig = self.build_addition_rig(tex_coeff[i - 1][-1], tex_coeff[i - 1][0])
-            self.play(FadeIn(tex_coeff[i - 1][-1]), FadeIn(tex_coeff[i - 1][i]))
-            self.wait(1)
-            self.play(FadeIn(add_rig), Write(tex_coeff[i][0]))
-            for j in range(1, i + 1):
-                self.play(add_rig.animate.shift(2 * RIGHT))
-                self.play(Write(tex_coeff[i][j]))
-            self.play(FadeOut(tex_coeff[i - 1][-1]), FadeOut(tex_coeff[i - 1][i]), FadeOut(add_rig))
-
-
-    def build_addition_rig(self, left_el, right_el):
-        plus = MathTex("+")
-        plus.move_to((left_el.get_center() + right_el.get_center()) / 2.0)
-        arrow = Arrow(start = 0.75 * UP, end = 0.75 * DOWN)
-        arrow.next_to(plus, DOWN * 1.5)
-        add_rig = VGroup(*[plus, arrow])
-        return(add_rig)
-
 class PascalMonomials(Scene):
     def construct(self):
         coeff_data = [(int_binom(4, i), i) for i in range(0, 5)]