Removes gradient descent and begins refactor
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This commit is contained in:
Deepak Mallubhotla 2021-08-29 10:54:36 -05:00
parent 359e048531
commit c279f1b470
Signed by: deepak
GPG Key ID: 64BF53A3369104E7
8 changed files with 161 additions and 160 deletions

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@ -1,29 +0,0 @@
import numpy
def find_sols(cost_array, jacobian, step_size=0.001, max_iterations=5, initial=(0, 0), desired_cost=1e-6, step_size_tries=30):
desired_cost_squared = desired_cost**2
current = numpy.array(initial)
iterations = 0
curr_cost = numpy.array(cost_array(current))
def total_cost(x):
cost = numpy.array(cost_array(x))
return cost.dot(cost)
while iterations < max_iterations:
curr_cost = numpy.array(cost_array(current))
if curr_cost.dot(curr_cost) < desired_cost_squared:
return ("Finished early", iterations, current)
gradient = .5 * numpy.matmul(numpy.transpose(jacobian(current)), curr_cost)
tries = step_size_tries
current_step = step_size
while total_cost(current - current_step * gradient) > (total_cost(current) - 0.5 * current_step * gradient.dot(gradient)):
current_step = current_step * .8
tries -= 1
if tries == 0:
return ("hit minimum step size", iterations, current)
current = current - current_step * gradient
iterations += 1
return ("Ran out of iterations", iterations, current)

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@ -1,4 +1,5 @@
from pathfinder.model.dot import Dot
from pathfinder.model.dot import DotMeasurement
from pathfinder.model.model import DotDipoleModel
from pathfinder.model.staticdipole import StaticDipole
__all__ = ['Dot', 'DotDipoleModel', ]
__all__ = ['DotMeasurement', 'DotDipoleModel', 'StaticDipole']

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@ -2,9 +2,11 @@ from dataclasses import dataclass
import numpy
import numpy.typing
from pathfinder.model.staticdipole import StaticDipole
@dataclass
class Dot():
class DotMeasurement():
'''
Representation of a dot measuring static dipoles.
@ -13,20 +15,32 @@ class Dot():
v : float
The voltage measured at the dot.
r : numpy.ndarray
The number of dots used to sample the potential.
The position of the dot.
'''
v: float
r: numpy.typing.ArrayLike
r: numpy.ndarray
def __post_init__(self) -> None:
self.r = numpy.array(self.r)
def v_for_point(self, pt: numpy.ndarray) -> float:
'''
Returns the voltage for a static dipole represented as a phase space point.
Parameters
----------
pt: A length 6 numpy array representing a dipole, as (px, py, pz, sx, sy, sz).
Returns
----------
Returns the voltage from that dipole at the point.
'''
p = pt[0:3] # hardcoded here because chances
s = pt[3:6] # are we'll only ever work in 3d.
diff = self.r - s
return p.dot(diff) / (numpy.linalg.norm(diff)**3)
dipole = StaticDipole(p, s)
return dipole.v_at_position(self.r)
def cost(self, pts: numpy.ndarray) -> float:
# 6 because dipole in 3d has 6 degrees of freedom.

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@ -1,7 +1,7 @@
from typing import Callable, Sequence
import numpy
from pathfinder.model.dot import Dot
from pathfinder.model.dot import DotMeasurement
class DotDipoleModel():
@ -16,7 +16,7 @@ class DotDipoleModel():
n: int
The number of dipoles to assume.
'''
def __init__(self, dots: Sequence[Dot], n: int) -> None:
def __init__(self, dots: Sequence[DotMeasurement], n: int) -> None:
self.dots = dots
self.m = len(dots)
self.n = n
@ -29,3 +29,9 @@ class DotDipoleModel():
return numpy.array([dot.cost(pt) for dot in self.dots])
return costs_to_return
def jac(self) -> Callable[[numpy.ndarray], numpy.ndarray]:
def jac_to_return(pts: numpy.ndarray) -> numpy.ndarray:
return numpy.array([dot.jac(pts) for dot in self.dots])
return jac_to_return

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@ -0,0 +1,31 @@
from dataclasses import dataclass
import numpy
import numpy.typing
@dataclass
class StaticDipole():
'''
Representation of a static dipoles, either known or guessed.
Parameters
----------
p : numpy.ndarray
The static dipole moment.
s : numpy.ndarray
The position of the dipole.
'''
p: numpy.ndarray
s: numpy.ndarray
def __post_init__(self) -> None:
'''
Coerce the inputs into numpy arrays.
'''
self.p = numpy.array(self.p)
self.s = numpy.array(self.s)
def v_at_position(self, r: numpy.typing.ArrayLike) -> float:
diff = r - self.s
return self.p.dot(diff) / (numpy.linalg.norm(diff)**3)

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@ -5,14 +5,14 @@ import pathfinder.model as model
def test_dot():
dot = model.Dot(0.235, (1, 2, 3))
dot = model.DotMeasurement(0.235, (1, 2, 3))
assert dot.v == 0.235
numpy.testing.assert_array_equal(dot.r, (1, 2, 3), "These arrays should have been equal!")
def test_dot_v_from_dipole():
# for a dot located at (1, 2, 3)
dot = model.Dot(50, (1, 2, 3))
dot = model.DotMeasurement(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))
@ -27,7 +27,7 @@ def test_dot_v_from_dipole():
def test_dot_jac():
# for a dot located at (1, 2, 3)
dot = model.Dot(50, (1, 2, 3))
dot = model.DotMeasurement(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))

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@ -1,4 +1,7 @@
import numpy
import pathfinder.model as model
import scipy.optimize
import pytest
def test_dotdipolemodel_repr():
@ -7,5 +10,98 @@ def test_dotdipolemodel_repr():
def test_dotdipolemodel_m():
mod = model.DotDipoleModel([model.Dot(1, (0, 0, 0)), model.Dot(2, (0, 0, 0))], 1)
mod = model.DotDipoleModel([model.DotMeasurement(1, (0, 0, 0)), model.DotMeasurement(2, (0, 0, 0))], 1)
assert mod.m == 2
def print_result(msg, result):
print(msg)
print(f"\tResult: {result.x}")
print(f"\tSuccess: {result.success}. {result.message}")
try:
print(f"\tFunc evals: {result.nfev}")
except AttributeError:
pass
try:
print(f"\tJacb evals: {result.njev}")
except AttributeError:
pass
@pytest.mark.skip(reason="old")
def test_dot_dipole_model_jac():
v1 = -0.05547767706400186526225414
v2 = -0.06018573388098888319642888
v3 = -0.06364032191901859480476888
v4 = -0.06488383879243851188402150
v5 = -0.06297148063759813929659130
v6 = -0.05735489606460216
v7 = -0.07237320672886623
v8 = -0.1082531754730548
c1 = model.DotMeasurement(v1, [0, 0, 1])
c2 = model.DotMeasurement(v2, [0, 0, 2])
c3 = model.DotMeasurement(v3, [0, 0, 3])
c4 = model.DotMeasurement(v4, [0, 0, 4])
c5 = model.DotMeasurement(v5, [0, 0, 5])
c6 = model.DotMeasurement(v6, [0, 0, 6])
c7 = model.DotMeasurement(v7, [1, 1, 7])
c8 = model.DotMeasurement(v8, [1, 2, 3])
mod = model.DotDipoleModel([c1, c2, c3, c4, c5, c6], 1)
res = scipy.optimize.least_squares(mod.costs(), numpy.array([1, 2, 3, 4, 5, 6]), jac=mod.jac(), ftol=1e-12)
print_result("6 dots, least sq", res)
mod2 = model.DotDipoleModel([c1, c2, c3, c4, c5, c6, c7, c8], 1)
res2 = scipy.optimize.least_squares(mod2.costs(), numpy.array([0, 0, 0, 0, 0, 0]), jac=mod2.jac(), ftol=1e-12, gtol=3e-16)
print_result("7 dots, least squares", res2)
print(mod2.costs()(res2.x))
print(mod2.costs()(numpy.array([1, 3, 5, 5, 6, 7])))
@pytest.mark.skip(reason="bad test")
def test_dot_2dipoles_model_jac():
dots_12andone = [
model.DotMeasurement(-0.1978319326584865, [-4, -1, 0]),
model.DotMeasurement(-0.1273171638293727, [-4, -5, 0]),
model.DotMeasurement(-0.05545025617224288, [-4, -9, 0]),
model.DotMeasurement(-0.4960209997369774, [-1, -1, 0]),
model.DotMeasurement(-0.1763373289754278, [-1, -5, 0]),
model.DotMeasurement(-0.04946346672578462, [-1, -9, 0]),
model.DotMeasurement(-0.5633156098386561, [1, -1, 0]),
model.DotMeasurement(-0.113765134433174, [1, -5, 0]),
model.DotMeasurement(-0.0294893572499722, [1, -9, 0]),
model.DotMeasurement(0.7794941616360612, [4, -1, 0]),
model.DotMeasurement(0.1110683086477768, [4, -5, 0]),
model.DotMeasurement(0.01183272220840589, [4, -9, 0]),
model.DotMeasurement(-0.1096485462119833, [1, 1, 1]),
model.DotMeasurement(-0.3925851888077783, [1, 1, -1])
]
# dots = [
# model.Dot(-0.1978319326584865, [-4, -1, 0]),
# model.Dot(-0.1273171638293727, [-4, -5, 0]),
# model.Dot(-0.05545025617224288, [-4, -9, 0]),
# model.Dot(-0.4960209997369774, [-1, -1, 0]),
# model.Dot(-0.1763373289754278, [-1, -5, 0]),
# model.Dot(-0.04946346672578462, [-1, -9, 0]),
# model.Dot(-0.5633156098386561, [1, -1, 0]),
# model.Dot(-0.113765134433174, [1, -5, 0]),
# model.Dot(-0.0294893572499722, [1, -9, 0]),
# model.Dot(0.7794941616360612, [4, -1, 0]),
# model.Dot(0.1110683086477768, [4, -5, 0]),
# model.Dot(0.01183272220840589, [4, -9, 0]),
# model.Dot(-0.0261092728062841, [-4, -13, 0]),
# model.Dot(-0.02035559593904894, [-1, -13, 0]),
# model.Dot(-0.01296894715810522, [1, -13, 0]),
# model.Dot(0.0003306001626435171, [4, -13, 0]),
# model.Dot(0.2612817068810759, [7, -1, 0]),
# model.Dot(0.1203841445911355, [7, -5, 0]),
# model.Dot(0.03425933872931543, [7, -9, 0]),
# model.Dot(0.01068547688208644, [7, -13, 0]),
# ]
mod = model.DotDipoleModel(dots_12andone, 2)
res = scipy.optimize.least_squares(mod.costs(), numpy.array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]), jac=mod.jac(), ftol=1e-12)
print_result("6 dots, least sq", res)
print(mod.costs()(res.x))
for val in res.x:
print(val)

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@ -1,118 +0,0 @@
import numpy
import pathfinder.gradient_descent
def circ_cost(radius, center=(0, 0)):
def cf(pt):
pt2 = numpy.array(pt) - numpy.array(center)
return (radius**2 - pt2.dot(pt2))
return cf
def test_circ_cost():
cost = circ_cost(5)
actual = cost([3, 4])
expected = 0
assert actual == expected
cost = circ_cost(13, [12, 5])
actual = cost([0, 0])
expected = 0
assert actual == expected
def test_find_sols():
c1 = circ_cost(5)
c2 = circ_cost(13, [8, -8])
def costs(pt):
return numpy.array(
[c1(pt), c2(pt)]
)
def jac(pt):
x, y = pt
return numpy.array([[-2 * x, -2 * y], [-2 * (x - 8), -2 * (y + 8)]])
message, iterations, result = pathfinder.gradient_descent.find_sols(costs, jac, step_size=0.01, max_iterations=5000, initial=(2, 10), desired_cost=1e-6)
numpy.testing.assert_almost_equal(
result, (3, 4),
decimal=7, err_msg='the result was off', verbose=True
)
def dipole_cost(vn, xn_raw):
xn = numpy.array(xn_raw)
def dc(pt):
p = pt[0:3]
s = pt[3:6]
diff = xn - s
return (vn * (numpy.linalg.norm(diff)**3)) - p.dot(diff)
return dc
def test_actual_dipole_finding():
def c0(pt):
p = pt[0:3]
return (p.dot(p) - 35)
v1 = -0.05547767706400186526225414
v2 = -0.06018573388098888319642888
v3 = -0.06364032191901859480476888
v4 = -0.06488383879243851188402150
v5 = -0.06297148063759813929659130
# the 0 here is a red herring for index purposes later
vns = [0, v1, v2, v3, v4, v5]
# the 0 here is a red herring
xns = [numpy.array([0, 0, n]) for n in range(0, 6)]
c1 = dipole_cost(v1, [0, 0, 1])
c2 = dipole_cost(v2, [0, 0, 2])
c3 = dipole_cost(v3, [0, 0, 3])
c4 = dipole_cost(v4, [0, 0, 4])
c5 = dipole_cost(v5, [0, 0, 5])
def costs(pt):
return numpy.array(
[c0(pt), c1(pt), c2(pt), c3(pt), c4(pt), c5(pt)]
)
def jac_row(n):
def jr(pt):
p = pt[0:3]
s = pt[3:6]
vn = vns[n]
xn = xns[n]
diff = xn - s
return [
-diff[0], -diff[1], -diff[2],
p[0] - vn * 3 * numpy.linalg.norm(diff) * (diff)[0],
p[1] - vn * 3 * numpy.linalg.norm(diff) * (diff)[1],
p[2] - vn * 3 * numpy.linalg.norm(diff) * (diff)[2]
]
return jr
def jac(pt):
return numpy.array([
[2 * pt[0], 2 * pt[1], 2 * pt[2], 0, 0, 0],
jac_row(1)(pt),
jac_row(2)(pt),
jac_row(3)(pt),
jac_row(4)(pt),
jac_row(5)(pt),
])
_, iterations, result = pathfinder.gradient_descent.find_sols(costs, jac, step_size=1, max_iterations=10000, initial=(1, 2, 3, 4, 5, 6), desired_cost=1e-6, step_size_tries=30)
print(f"\n\n{iterations} iterations")
print(result)
print("\n")
numpy.testing.assert_allclose(
result, (1, 3, 5, 5, 6, 7),
rtol=5e-2, err_msg='the result was off', verbose=True
)