public-mirrors/3b1b-manim
1
0
Fork 0
mirror of https://github.com/3b1b/manim.git synced 2025-08-05 16:49:03 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Changed get_quadratic_approximation_of_cubic

Browse source
This commit is contained in:
Grant Sanderson 2020-06-08 20:40:39 -07:00
parent ccefbc0dea
commit f0a36329b1
1 changed files with 9 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
manimlib/utils/bezier.py
View file

@ -3,6 +3,7 @@ import numpy as np
from manimlib.utils.simple_functions import choose from manimlib.utils.simple_functions import choose
from manimlib.utils.space_ops import find_intersection from manimlib.utils.space_ops import find_intersection
from manimlib.utils.space_ops import cross2d
CLOSED_THRESHOLD = 0.001 CLOSED_THRESHOLD = 0.001
@ -182,26 +183,21 @@ def get_quadratic_approximation_of_cubic(a0, h0, h1, a1):
q = h1 - 2 * h0 + a0 q = h1 - 2 * h0 + a0
r = a1 - 3 * h1 + 3 * h0 - a0 r = a1 - 3 * h1 + 3 * h0 - a0
def cross2d(v, w):
return v[:, 0] * w[:, 1] - v[:, 1] * w[:, 0]
a = cross2d(q, r) a = cross2d(q, r)
b = cross2d(p, r) b = cross2d(p, r)
c = cross2d(p, q) c = cross2d(p, q)
disc = b * b - 4 * a * c disc = b * b - 4 * a * c
has_infl &= (disc > 0) has_infl &= (disc > 0)
sqrt_disc = np.sqrt(abs(disc)) sqrt_disc = np.sqrt(np.abs(disc))
# print(a, b, c, sqrt_disc)
settings = np.seterr(all='ignore') settings = np.seterr(all='ignore')
ti_min, ti_max = [ ti_bounds = []
np.true_divide( for sgn in [-1, +1]:
-b + sgn * sqrt_disc, 2 * a, ti = (-b + sgn * sqrt_disc) / (2 * a)
out=(-c / b), ti[a == 0] = (-c / b)[a == 0]
where=(a != 0), ti[(a == 0) & (b == 0)] = 0
) ti_bounds.append(ti)
for sgn in [-1, +1] ti_min, ti_max = ti_bounds
]
np.seterr(**settings) np.seterr(**settings)
ti_min_in_range = has_infl & (0 < ti_min) & (ti_min < 1) ti_min_in_range = has_infl & (0 < ti_min) & (ti_min < 1)
ti_max_in_range = has_infl & (0 < ti_max) & (ti_max < 1) ti_max_in_range = has_infl & (0 < ti_max) & (ti_max < 1)