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Ensure valid range for arccos function -1 to 1 #4

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Ensure valid range for arccos function -1 to 1
alanpawlak Jan 20, 2023
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Typo
alanpawlak Jan 20, 2023
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4 changes: 2 additions & 2 deletions src/sphstat/descriptives.py
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Original file line number Diff line number Diff line change
Expand Up @@ -128,7 +128,7 @@ def rotationmatrix_withaxis(ua: np.array, ub: np.array) -> np.ndarray:
ca /= np.linalg.norm(ca)
B = ub.reshape((3, 1)) @ ca.reshape((1, 3))
B -= B.T
th = np.arccos(ab)
th = np.arccos(np.clip(ab, -1.0, 1.0))
A = np.eye(3) + np.sin(th) * B + (np.cos(th) - 1) * ((ub.reshape((3, 1)) @ ub.reshape((1, 3))) + ca.reshape((3, 1))
@ ca.reshape((1, 3)))
return A
Expand Down Expand Up @@ -381,7 +381,7 @@ def errmin(thph, sample):
pts = sample['points']
err = 0
for pt in pts:
err += np.arccos(np.dot(pt, x))
err += np.arccos(np.clip(np.dot(pt, x), -1.0, 1.0))
return err
# We will use Nelder-Mead to minimise the arc lengths
res = minimize(errmin, np.array([ms[0], ms[1]]), args = (sample), method='Nelder-Mead', tol=1e-6)
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4 changes: 2 additions & 2 deletions src/sphstat/distributions.py
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Expand Up @@ -289,7 +289,7 @@ def watson(numsamp: int, lamb: float, mu: float, nu: float, kappa: float) -> dic
U = rng.uniform(0, 1, 1)
V = rng.uniform(0, 1, 1)
S = 1 / kappa * np.log(U / C + 1)
the = np.arccos(S)
the = np.arccos(np.clip(S, -1.0, 1.0))
phi = 2 * np.pi * rng.uniform(0, 1, 1)
sample['tetas'].append(the)
sample['phis'].append(phi)
Expand All @@ -310,7 +310,7 @@ def watson(numsamp: int, lamb: float, mu: float, nu: float, kappa: float) -> dic
U = rng.uniform(0, 1, 1)
V = rng.uniform(0, 1, 1)
S = (1 / c1) * np.tan(c2 * U)
the = np.arccos(S)
the = np.arccos(np.clip(S, -1.0, 1.0))
phi = 2 * np.pi * rng.uniform(0, 1, 1)
sample['tetas'].append(the)
sample['phis'].append(phi)
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2 changes: 1 addition & 1 deletion src/sphstat/twosample.py
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Expand Up @@ -898,5 +898,5 @@ def errors(samplecart: dict, srcpos: tuple) -> list:
errs = []
srcvec = sph2cart(srcpos[0], srcpos[1])
for pt in samplecart['points']:
errs.append(np.arccos(np.dot(pt, srcvec)))
errs.append(np.arccos(np.clip(np.dot(pt, srcvec), -1.0, 1.0)))
return errs
4 changes: 2 additions & 2 deletions src/sphstat/utils.py
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Expand Up @@ -258,7 +258,7 @@ def angle(pt1: np.ndarray, pt2: np.ndarray) -> float:
assert type(pt2) == np.ndarray
assert np.isclose(np.linalg.norm(pt1), 1)
assert np.isclose(np.linalg.norm(pt2), 1)
return np.arccos(np.dot(pt1, pt2))
return np.arccos(np.clip(np.dot(pt1, pt2), -1.0, 1.0))


def cart2sph(pt: np.array) -> tuple:
Expand All @@ -270,7 +270,7 @@ def cart2sph(pt: np.array) -> tuple:
:rtype: tuple
"""
assert np.isclose(np.linalg.norm(pt), 1)
th = np.arccos(pt[2])
th = np.arccos(np.clip(pt[2], -1.0, 1.0))
if pt[1] == 0:
ph = 0
return th, ph
Expand Down