Reorganized files for 3b1b videos into a 3b1b_projects folder

3b1b_projects/active/diffyq/part1/shared_constructs.py

@@ -0,0 +1,118 @@
+from manimlib.imports import *
+
+
+Lg_formula_config = {
+    "tex_to_color_map": {
+        "\\theta_0": WHITE,
+        "{L}": BLUE,
+        "{g}": YELLOW,
+    },
+}
+
+
+class You(PiCreature):
+    CONFIG = {
+        "color": BLUE_C,
+    }
+
+
+def get_ode():
+    tex_config = {
+        "tex_to_color_map": {
+            "{\\theta}": BLUE,
+            "{\\dot\\theta}": RED,
+            "{\\ddot\\theta}": YELLOW,
+            "{t}": WHITE,
+            "{\\mu}": WHITE,
+        }
+    }
+    ode = TexMobject(
+        "{\\ddot\\theta}({t})", "=",
+        "-{\\mu} {\\dot\\theta}({t})",
+        "-{g \\over L} \\sin\\big({\\theta}({t})\\big)",
+        **tex_config,
+    )
+    return ode
+
+
+def get_period_formula():
+    return TexMobject(
+        "2\\pi", "\\sqrt{\\,", "L", "/", "g", "}",
+        tex_to_color_map={
+            "L": BLUE,
+            "g": YELLOW,
+        }
+    )
+
+
+def pendulum_vector_field_func(point, mu=0.1, g=9.8, L=3):
+    theta, omega = point[:2]
+    return np.array([
+        omega,
+        -np.sqrt(g / L) * np.sin(theta) - mu * omega,
+        0,
+    ])
+
+
+def get_vector_symbol(*texs, **kwargs):
+    config = {
+        "include_background_rectangle": True,
+        "bracket_h_buff": SMALL_BUFF,
+        "bracket_v_buff": SMALL_BUFF,
+        "element_alignment_corner": ORIGIN,
+    }
+    config.update(kwargs)
+    array = [[tex] for tex in texs]
+    return Matrix(array, **config)
+
+
+def get_heart_var(index):
+    heart = SuitSymbol("hearts")
+    if index == 1:
+        heart.set_color(BLUE_C)
+    elif index == 2:
+        heart.set_color(GREEN)
+    heart.set_height(0.7)
+    index = Integer(index)
+    index.move_to(heart.get_corner(DR))
+    heart.add(index)
+    return heart
+
+
+def get_heart_var_deriv(index):
+    heart = get_heart_var(index)
+    filler_tex = "T"
+    deriv = TexMobject("{d", filler_tex, "\\over", "dt}")
+    deriv.scale(2)
+    filler = deriv.get_part_by_tex(filler_tex)
+    heart.match_height(filler)
+    heart.move_to(filler)
+    heart.scale(1.5, about_edge=UL)
+    deriv.remove(filler)
+    deriv.add(heart)
+    deriv.heart = heart
+    return deriv
+
+
+def get_love_equation1():
+    equation = VGroup(
+        get_heart_var_deriv(1),
+        TexMobject("=").scale(2),
+        TexMobject("a").scale(2),
+        get_heart_var(2)
+    )
+    equation.arrange(RIGHT)
+    equation[-1].shift(SMALL_BUFF * DL)
+    return equation
+
+
+def get_love_equation2():
+    equation = VGroup(
+        get_heart_var_deriv(2),
+        TexMobject("=").scale(2),
+        TexMobject("-b").scale(2),
+        get_heart_var(1),
+    )
+    equation.arrange(RIGHT)
+    equation[-1].shift(SMALL_BUFF * DL)
+    return equation