3b1b-manim/manimlib/utils/simple_functions.py

99 lines
2.3 KiB
Python

from functools import reduce
import inspect
import numpy as np
import operator as op
def sigmoid(x):
return 1.0 / (1 + np.exp(-x))
CHOOSE_CACHE = {}
def choose_using_cache(n, r):
if n not in CHOOSE_CACHE:
CHOOSE_CACHE[n] = {}
if r not in CHOOSE_CACHE[n]:
CHOOSE_CACHE[n][r] = choose(n, r, use_cache=False)
return CHOOSE_CACHE[n][r]
def choose(n, r, use_cache=True):
if use_cache:
return choose_using_cache(n, r)
if n < r:
return 0
if r == 0:
return 1
denom = reduce(op.mul, range(1, r + 1), 1)
numer = reduce(op.mul, range(n, n - r, -1), 1)
return numer // denom
def get_num_args(function):
return len(get_parameters(function))
def get_parameters(function):
return inspect.signature(function).parameters
# Just to have a less heavyweight name for this extremely common operation
#
# We may wish to have more fine-grained control over division by zero behavior
# in the future (separate specifiable values for 0/0 and x/0 with x != 0),
# but for now, we just allow the option to handle indeterminate 0/0.
def clip(a, min_a, max_a):
if a < min_a:
return min_a
elif a > max_a:
return max_a
return a
def clip_in_place(array, min_val=None, max_val=None):
if max_val is not None:
array[array > max_val] = max_val
if min_val is not None:
array[array < min_val] = min_val
return array
def fdiv(a, b, zero_over_zero_value=None):
if zero_over_zero_value is not None:
out = np.full_like(a, zero_over_zero_value)
where = np.logical_or(a != 0, b != 0)
else:
out = None
where = True
return np.true_divide(a, b, out=out, where=where)
def binary_search(function,
target,
lower_bound,
upper_bound,
tolerance=1e-4):
lh = lower_bound
rh = upper_bound
while abs(rh - lh) > tolerance:
mh = np.mean([lh, rh])
lx, mx, rx = [function(h) for h in (lh, mh, rh)]
if lx == target:
return lx
if rx == target:
return rx
if lx <= target and rx >= target:
if mx > target:
rh = mh
else:
lh = mh
elif lx > target and rx < target:
lh, rh = rh, lh
else:
return None
return mh