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Adds jacobian rows to dot

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This commit is contained in:
Deepak Mallubhotla 2021-08-24 14:00:39 -05:00
parent 7230d37244
commit 359e048531
Signed by: deepak
GPG Key ID: 64BF53A3369104E7
2 changed files with 41 additions and 0 deletions
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21
pathfinder/model/dot.py
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@ -35,3 +35,24 @@ class Dot():
# Will throw problems for irregular points, but that's okay for now.
chunked_pts = [pts[i: i + pt_length] for i in range(0, len(pts), pt_length)]
return sum(self.v_for_point(pt) for pt in chunked_pts) - self.v
def jac_pt(self, pt: numpy.ndarray) -> numpy.ndarray:
p = pt[0:3] # hardcoded here because chances
s = pt[3:6] # are we'll only ever work in 3d.
diff = self.r - s
p_divs = diff / (numpy.linalg.norm(diff)**3)
r_divs = -p / (numpy.linalg.norm(diff)**3) + 3 * p.dot(diff) * diff / (numpy.linalg.norm(diff)**5)
return numpy.append(p_divs, r_divs)
def jac(self, pts: numpy.ndarray) -> numpy.ndarray:
# 6 because dipole in 3d has 6 degrees of freedom.
pt_length = 6
# creates numpy.ndarrays in groups of pt_length.
# Will throw problems for irregular points, but that's okay for now.
chunked_pts = [pts[i: i + pt_length] for i in range(0, len(pts), pt_length)]
return numpy.append([], [self.jac_pt(pt) for pt in chunked_pts])

20
tests/model/test_dot.py
View File

@ -23,3 +23,23 @@ def test_dot_v_from_dipole():
numpy.testing.assert_allclose(dot.v_for_point(pt), target, err_msg="v from dipole at a dot was incorrect!")
numpy.testing.assert_allclose(dot.cost(pt), cost, err_msg="cost from dipole at a dot was incorrect!")
def test_dot_jac():
# for a dot located at (1, 2, 3)
dot = model.Dot(50, (1, 2, 3))
# and dipole located at (4, 7, 11) with p=(8, 9, 10)
pt = numpy.array((8, 9, 10, 4, 7, 11))
target_jac_pt = [-0.003092303707812889, -0.005153839513021483, -0.00824614322083437, 0.0058585481811285, 0.01423090787983279, 0.02730483137919137]
# assume a second dipole at (12, 13, -5), with p = (-1, -2, -3)
second_target = [-0.002054993939616119, -0.002054993939616119, 0.001494541046993541, 5.494636202182148e-6, 0.0001923122670763748, 0.0006923241614749492]
pt2 = numpy.array((-1, -2, -3, 12, 13, -5))
jac_row_target = target_jac_pt + second_target
pts = numpy.append(pt, pt2)
assert len(dot.jac_pt(pt)) == 6
numpy.testing.assert_allclose(dot.jac_pt(pt), target_jac_pt, err_msg="Jac pt doesn't match Mathematica result.")
numpy.testing.assert_allclose(dot.jac(pts), jac_row_target, err_msg="whole row should match")