Update example.py

1 files changed, 49 insertions, 13 deletions

diff --git a/FSF-2020/approximations-and-optimizations/Critical Points/example.py b/FSF-2020/approximations-and-optimizations/Critical Points/example.py
index 46c8bd9..bdbb6ed 100644
--- a/FSF-2020/approximations-and-optimizations/Critical Points/example.py
+++ b/FSF-2020/approximations-and-optimizations/Critical Points/example.py
@@ -4,30 +4,66 @@ class ExampleAnimation(ThreeDScene):
     def construct(self):
         axes = ThreeDAxes()
 
+        f_text = TextMobject("$f(x,y) = (y-x)(1-2x-3y)$").to_corner(UL)        
+        d = Dot(np.array([0,0,0]), color = '#800000')  #---- Critical Point
+        d_text = TextMobject("$(0.2,0.2)$",color = '#DC143C').scale(0.5).shift(0.2*UP)  #----x = 0.2, y = 0.2
+        r_text=TextMobject("Critical Point",color = '#00FFFF').shift(0.3*DOWN).scale(0.6)
+
         #----f(x,y) = (y-x)(1-2x-3y)
-        e = ParametricSurface(
+        f = ParametricSurface(
             lambda u, v: np.array([
                 u,
                 v,
                 (v-u)*(1-2*u-3*v)
             ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [PURPLE_D, PURPLE_E],
-            resolution=(20, 20)).scale(1)
-        
-        self.set_camera_orientation(phi = 35 * DEGREES, theta = -40 * DEGREES)
+            resolution=(20, 20)).scale(1)       
         
-        f_text = TextMobject("$f(x,y) = (y-x)(1-2x-3y)$").to_corner(UL)
-        d = Dot(np.array([0,0,0]), color = '#800000')  #---- Critical Point
-        d_text = TextMobject("$(0.2,0.2)$",color = '#DC143C').scale(0.5).shift(0.2*UP)  #----x = 0.2, y = 0.2
-        r_text = TextMobject("Critical Point",color = '#00FFFF').shift(0.3*DOWN).scale(0.6)
+        fx_text = TextMobject("$\\frac{\\partial f}{\\partial x} = 4x-1+y$").to_corner(UL)
+
+        #----fx = 4x-1+y
+        fx = ParametricSurface(
+            lambda u, v: np.array([
+                u,
+                v,
+                4*u-1+v
+            ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [BLUE_D, BLUE_E],
+            resolution = (20, 20)).scale(1)
+
+        fy_text = TextMobject("$\\frac{\\partial f}{\\partial y} = -6y+1+x$").to_corner(UL)
+
+        #----fy = -6y+1+x
+        fy = ParametricSurface(
+            lambda u, v: np.array([
+                u,
+                v,
+                -6*v+1+u
+            ]),v_min = -1, v_max = 1, u_min = -1, u_max = 1, checkerboard_colors = [RED_D, RED_E],
+            resolution = (20, 20)).scale(1)
+
+        self.set_camera_orientation(phi = 75 * DEGREES)
+        self.begin_ambient_camera_rotation(rate=0.2)
+
+        group1 = VGroup(axes,f,d,d_text,r_text,f_text)
+        group2 = VGroup(axes,fx,fx_text)
 
         self.add_fixed_in_frame_mobjects(f_text)
-        self.wait(2)
+        self.wait(1) 
         self.add(axes)
-        self.play(Write(e))
-        self.wait(2)
-        self.play(ShowCreation(d))
+        self.play(Write(f),Write(d))
         self.wait(1)
         self.add_fixed_in_frame_mobjects(d_text)
         self.wait(1)
         self.add_fixed_in_frame_mobjects(r_text)
-        self.wait(3)
+        self.wait(2)
+        self.play(FadeOut(group1))
+        self.wait(1)
+        self.add_fixed_in_frame_mobjects(fx_text) 
+        self.add(axes)
+        self.play(Write(fx))
+        self.wait(2)
+        self.play(FadeOut(group2))
+        self.wait(1)
+        self.add_fixed_in_frame_mobjects(fy_text) 
+        self.add(axes)
+        self.play(Write(fy))
+        self.wait(2)