def test_out_nonstandard_strides():
x = np.array([1, 2, 0, 3, 4, 5])
base = np.zeros(2 * len(x))
out = base[::2]
y1 = backlash(x, 1, 1)
y2 = backlash(x, 1, 1, out=out)
assert_array_equal(y1, y2)
def test_nonstandard_strides():
t = np.linspace(0, 5, 11).reshape(-1, 1)
y = (10 * np.sin(t + [0, 1, np.pi / 2])).T[::2]
# y has strides (16, 24)
# y.copy() has strides (88, 8)
y1 = backlash(y, 1, 1, axis=1)
y2 = backlash(y.copy(order='C'), 1, 1)
assert_array_equal(y1, y2)
import numpy as np
import matplotlib.pyplot as plt
from ufunclab import backlash
t = np.linspace(0, 20, 1000)
x = (21 - t) * np.sin(t * t / 20) / 8
deadband = 1.0
y0 = 0.0
y = backlash(x, deadband, y0)
plt.figure(figsize=(6, 4))
plt.plot(t, x, linewidth=2, label='x(t)')
plt.plot(t, y, '--', linewidth=2, label='backlash(x(t))')
plt.plot(t,
x + deadband / 2,
'k:',
alpha=0.5,
linewidth=1,
label=f'x(t) ± {deadband/2}')
plt.plot(t, x - deadband / 2, 'k:', alpha=0.5, linewidth=1)
plt.title(f'Backlash, deadband={deadband}')
plt.legend(shadow=True)
plt.grid(alpha=0.6)
#plt.show()
plt.savefig('backlash_demo.png')
def test_all_zeros():
x = np.zeros(10)
y = backlash(x, 1, 0)
assert_array_equal(y, x)
def test_initial_b():
x = np.array([1.75, 2, 3, 2.9, -1])
y = backlash(x, 2, 0.5)
assert_array_equal(y, [0.75, 1, 2, 2, 0])
def test_basic():
x = np.array([0, 0, 1.5, 1.5, 1, 1, 1, -3, -3.25, -3])
y = backlash(x, 2, 0)
assert_array_equal(y, [0, 0, 0.5, 0.5, 0.5, 0.5, 0.5, -2, -2.25, -2.25])
def test_within_deadband():
x = np.array([0, 0, 0, 0.5, 0.5, 0.5, -0.75, -0.8])
y = backlash(x, 2, 0)
assert_array_equal(y, np.zeros_like(x))