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deepmind-research/fusion_tcv/targets.py
Nimrod Gileadi 3f0d5ed1a0 Internal change
PiperOrigin-RevId: 417034217
2022-02-16 16:08:46 +00:00

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Python

# Copyright 2021 DeepMind Technologies Limited.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS-IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Reward targets that return target+actual."""
import abc
import math
from typing import List, Optional, Sequence, Tuple
import dataclasses
import numpy as np
import scipy
from fusion_tcv import fge_state
from fusion_tcv import named_array
from fusion_tcv import shape
from fusion_tcv import tcv_common
class TargetError(Exception):
"""For when a target can't be computed."""
@dataclasses.dataclass(frozen=True)
class Target:
actual: float
target: float
@classmethod
def invalid(cls):
"""This target is invalid and should be ignored. Equivalent to weight=0."""
return cls(float("nan"), float("nan"))
class AbstractTarget(abc.ABC):
"""Measure something about the simulation, with a target and actual value."""
@property
def name(self) -> str:
"""Returns a name for the target."""
return self.__class__.__name__
@abc.abstractproperty
def outputs(self) -> int:
"""Return the number of outputs this produces."""
@abc.abstractmethod
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
"""Returns a list of targets."""
@dataclasses.dataclass(frozen=True)
class AbstractSingleValuePerDomainTarget(AbstractTarget):
"""Base class for single value per plasma domain targets."""
target: Optional[Sequence[float]] = None
indices: List[int] = dataclasses.field(default_factory=lambda: [0])
def __post_init__(self):
if self.indices not in ([0], [1], [0, 1]):
raise ValueError(
f"Invalid indices: {self.indices}, must be [0], [1] or [0, 1].")
if self.target and len(self.target) != len(self.indices):
raise ValueError("Wrong number of targets.")
@property
def outputs(self) -> int:
return len(self.indices)
@property
def name(self) -> str:
return f"{super().name}: " + ",".join(str(i) for i in self.indices)
@dataclasses.dataclass(frozen=True)
class R(AbstractSingleValuePerDomainTarget):
"""Target for R."""
def __call__(self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
r_d, _, _ = state.rzip_d
if self.target is None:
return [Target(r_d[idx], references["R"][idx]) for idx in self.indices]
else:
return [Target(r_d[idx], target)
for idx, target in zip(self.indices, self.target)]
@dataclasses.dataclass(frozen=True)
class Z(AbstractSingleValuePerDomainTarget):
"""Target for Z."""
def __call__(self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
_, z_d, _ = state.rzip_d
if self.target is None:
return [Target(z_d[idx], references["Z"][idx]) for idx in self.indices]
else:
return [Target(z_d[idx], target)
for idx, target in zip(self.indices, self.target)]
@dataclasses.dataclass(frozen=True)
class Ip(AbstractSingleValuePerDomainTarget):
"""Target for Ip."""
def __call__(self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
_, _, ip_d = state.rzip_d
if self.target is None:
return [Target(ip_d[idx], references["Ip"][idx]) for idx in self.indices]
else:
return [Target(ip_d[idx], target)
for idx, target in zip(self.indices, self.target)]
class OHCurrentsClose(AbstractTarget):
"""Target for keeping OH currents close."""
@property
def outputs(self) -> int:
return 1
def __call__(self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
oh_coil_currents = state.get_coil_currents_by_type("OH")
diff = abs(oh_coil_currents[0] - oh_coil_currents[1])
return [Target(diff, 0)]
class EFCurrents(AbstractTarget):
"""EFCurrents, useful for avoiding stuck coils."""
@property
def outputs(self) -> int:
return 16
def __call__(self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
currents = np.concatenate([state.get_coil_currents_by_type("E"),
state.get_coil_currents_by_type("F")])
return [Target(c, 0) for c in currents]
@dataclasses.dataclass(frozen=True)
class VoltageOOB(AbstractTarget):
"""Target for how much the voltages exceed the bounds."""
relative: bool = True
@property
def outputs(self) -> int:
return tcv_common.NUM_ACTIONS
def __call__(self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
bounds = tcv_common.action_spec()
excess = (np.maximum(bounds.minimum - voltages, 0) +
np.maximum(voltages - bounds.maximum, 0))
if self.relative:
excess /= (bounds.maximum - bounds.minimum)
return [Target(v, 0) for v in excess]
@dataclasses.dataclass(frozen=True)
class ShapeElongation(AbstractSingleValuePerDomainTarget):
"""Try to keep the elongation close to the references."""
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.target is not None:
targets = self.target
else:
targets = references["kappa"][self.indices]
return [Target(state.elongation[i], target)
for i, target in zip(self.indices, targets)]
@dataclasses.dataclass(frozen=True)
class ShapeTriangularity(AbstractSingleValuePerDomainTarget):
"""Try to keep the triangularity close to the references."""
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.target is not None:
targets = self.target
else:
targets = references["delta"][self.indices]
return [Target(state.triangularity[i], target)
for i, target in zip(self.indices, targets)]
@dataclasses.dataclass(frozen=True)
class ShapeRadius(AbstractSingleValuePerDomainTarget):
"""Try to keep the shape radius close to the references."""
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.target is not None:
targets = self.target
else:
targets = references["radius"][self.indices]
return [Target(state.radius[i], target)
for i, target in zip(self.indices, targets)]
@dataclasses.dataclass(frozen=True)
class AbstractPointsTarget(AbstractTarget):
"""Base class for shape point targets."""
points: Optional[shape.ShapePoints] = None
ref_name: Optional[str] = None
num_points: Optional[int] = None
def __post_init__(self):
if self.points is not None:
return
elif self.ref_name is None:
raise ValueError("Must specify points or ref_name")
else:
ref_name = f"{self.ref_name}_r"
if ref_name not in tcv_common.REF_RANGES:
raise ValueError(f"{self.ref_name} is invalid.")
elif (self.num_points is not None and
self.num_points > tcv_common.REF_RANGES.count(ref_name)):
raise ValueError(
(f"Requesting more points ({self.num_points}) than {self.ref_name} "
"provides."))
@property
def outputs(self) -> int:
return len(self.points) if self.points is not None else self.num_points
def _target_points(
self, references: named_array.NamedArray) -> shape.ShapePoints:
if self.points is not None:
return self.points
else:
return shape.points_from_references(
references, self.ref_name, self.num_points)
def splined_lcfs_points(
state: fge_state.FGEState,
num_points: int,
domain: int = 0) -> shape.ShapePoints:
"""Return a smooth lcfs, cleaning FGE x-point artifacts."""
points = state.get_lcfs_points(domain)
x_point = (shape.Point(*state.limit_point_d[domain])
if state.is_diverted_d[domain] else None)
if x_point is not None:
x_points = [x_point]
# Drop points near the x-point due to noise in the shape projection near
# the x-point.
points = [p for p in points if shape.dist(p, x_point) > 0.1]
points.append(x_point)
points = shape.sort_by_angle(points)
else:
x_points = []
return shape.spline_interpolate_points(points, num_points, x_points)
@dataclasses.dataclass(frozen=True)
class ShapeLCFSDistance(AbstractPointsTarget):
"""Try to keep the shape close to the references.
Check the distance from the target shape points to the smooth LCFS.
"""
ref_name: str = dataclasses.field(default="shape", init=False)
domain: int = dataclasses.field(default=0, init=False)
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
lcfs = splined_lcfs_points(state, 90, self.domain)
outputs = []
for p in self._target_points(references):
if p.r == 0: # For invalid/changing number of points.
outputs.append(Target.invalid())
continue
dist = shape.dist_point_to_surface(np.array(lcfs), np.array(p))
outputs.append(Target(dist, 0))
return outputs
def flux_at_points(state: fge_state.FGEState, points: np.ndarray) -> np.ndarray:
"""Return the normalized interpolated flux values at a set of points."""
# Normalized flux such that the LCFS has a value of 1, 0 in the middle,
# and bigger than 1 farther out.
normalized_flux = ( # (LY.Fx - LY.FA) / (LY.FB - LY.FA)
(state.flux - state.magnetic_axis_flux_strength) /
(state.lcfs_flux_strength - state.magnetic_axis_flux_strength)).T
smooth_flux = scipy.interpolate.RectBivariateSpline(
np.squeeze(state.r_coordinates),
np.squeeze(state.z_coordinates),
normalized_flux)
return smooth_flux(points[:, 0], points[:, 1], grid=False)
@dataclasses.dataclass(frozen=True)
class ShapeNormalizedLCFSFlux(AbstractPointsTarget):
"""Try to keep the shape close to the references using flux.
Check the normalized flux values at points along the target shape. This works
in flux space, not linear distance, so may encourage smaller plasmas than the
distance based shape rewards.
"""
ref_name: str = dataclasses.field(default="shape1", init=False)
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
outputs = []
for p in self._target_points(references):
if p.r == 0: # For invalid/changing number of points.
outputs.append(Target.invalid())
else:
outputs.append(Target(
flux_at_points(state, np.array([p]))[0], 1))
return outputs
@dataclasses.dataclass(frozen=True)
class LegsNormalizedFlux(ShapeNormalizedLCFSFlux):
"""Try to keep the legs references close to the LCFS."""
ref_name: str = dataclasses.field(default="legs", init=False)
@dataclasses.dataclass(frozen=True)
class AbstractXPointTarget(AbstractPointsTarget):
"""Base class for x-point targets."""
ref_name: str = dataclasses.field(default="x_points", init=False)
@dataclasses.dataclass(frozen=True)
class XPointFluxGradient(AbstractXPointTarget):
"""Keep target points as an X point by attempting 0 flux gradient."""
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
eps = 0.01
targets = []
for point in self._target_points(references):
if point.r == 0: # For invalid/changing number of points.
targets.append(Target.invalid())
continue
diff_points = np.array([
[point.r - eps, point.z],
[point.r + eps, point.z],
[point.r, point.z - eps],
[point.r, point.z + eps],
])
flux_values = flux_at_points(state, diff_points)
diff = ((np.abs(flux_values[0] - flux_values[1]) / (2 * eps)) +
(np.abs(flux_values[2] - flux_values[3]) / (2 * eps)))
targets.append(Target(diff, 0))
return targets
def _dist(p1: shape.Point, p2: shape.Point):
return math.hypot(p1.r - p2.r, p1.z - p2.z)
def _min_dist(pt: shape.Point, points: shape.ShapePoints,
min_dist: float) -> Tuple[Optional[int], float]:
index = None
for i, point in enumerate(points):
dist = _dist(pt, point)
if dist < min_dist:
index = i
min_dist = dist
return index, min_dist
@dataclasses.dataclass(frozen=True)
class XPointDistance(AbstractXPointTarget):
"""Keep target points as an X point by attempting to minimize distance.
This assigns the x-points to targets without replacement. The first target
will get the distance to the nearest x-point. The second target will get the
closest, but ignoring the one assigned to the first target point. If none are
within `max_dist`, then no x-point is assigned and that distance will be
returned.
It may be worth switching to a fancier algorithm that tries to minimize the
total distance between targets and x-points, but that's slower, and we may
actually care about some x-points more (eg a diverted point is more
important than one farther away).
"""
max_dist: float = 0.2
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
x_points = state.x_points
targets = []
for target_point in self._target_points(references):
if target_point.r == 0: # For invalid/changing number of points.
targets.append(Target.invalid())
continue
index, min_dist = _min_dist(target_point, x_points, self.max_dist)
if index is not None:
x_points.pop(index)
targets.append(Target(min_dist, 0))
return targets
@dataclasses.dataclass(frozen=True)
class XPointFar(AbstractXPointTarget):
"""Keep extraneous x-points far away from the LCFS.
Returns the distance from the LCFS to any true x-point that is far from a
target x-point.
This assigns the x-points to targets without replacement. The first target
will get the distance to the nearest x-point. The second target will get the
closest, but ignoring the one assigned to the first target point. If none are
within `max_dist`, then no x-point is assigned and that distance will be
returned.
It may be worth switching to a fancier algorithm that tries to minimize the
total distance between targets and x-points, but that's slower, and we may
actually care about some x-points more (eg a diverted point is more
important than one farther away).
"""
max_dist: float = 0.2
domain: int = 0
diverted: Optional[shape.Diverted] = None
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.diverted is not None:
target = self.diverted
else:
target = shape.Diverted.from_refs(references)
if target == shape.Diverted.ANY:
return [] # Don't care.
x_points = state.x_points
# Filter out x-points that are near target x-points.
for target_point in self._target_points(references):
if target_point.r == 0: # For invalid/changing number of points.
continue
index, _ = _min_dist(target_point, x_points, self.max_dist)
if index is not None:
x_points.pop(index)
if not x_points:
return [Target(100, 0)] # No x-point gives full reward, not weight=0.
lcfs = state.get_lcfs_points(self.domain)
return [Target(shape.dist_point_to_surface(np.array(lcfs), np.array(p)), 0)
for p in x_points]
@dataclasses.dataclass(frozen=True)
class XPointNormalizedFlux(AbstractXPointTarget):
"""Keep the actual X points close to the LCFS.
Choose the x-points based on their distance to the target x-points.
"""
max_dist: float = 0.2
diverted: Optional[shape.Diverted] = None
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.diverted is not None:
diverted = self.diverted
else:
diverted = shape.Diverted.from_refs(references)
x_points = state.x_points
fluxes = list(flux_at_points(state, np.array(x_points).reshape((-1, 2))))
targets = []
# We should probably minimize the overall distance between targets and
# x-points, but the algorithm is complicated, so instead be greedy and
# assume they're given in priority order, or farther apart than max_dist.
for target_point in self._target_points(references):
if target_point.r == 0 or diverted != shape.Diverted.DIVERTED:
# For invalid/changing number of points.
targets.append(Target.invalid())
continue
index, _ = _min_dist(target_point, x_points, self.max_dist)
if index is not None:
targets.append(Target(fluxes[index], 1))
x_points.pop(index)
fluxes.pop(index)
else:
targets.append(Target(0, 1))
return targets
@dataclasses.dataclass(frozen=True)
class XPointCount(AbstractTarget):
"""Target for number of x-points. Useful to avoid more than you want."""
target: Optional[int] = None
@property
def outputs(self) -> int:
return 1
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.target is not None:
target = self.target
else:
target_points = shape.points_from_references(
references, "x_points", tcv_common.REF_RANGES.count("x_points_r"))
target = sum(1 for p in target_points if p.r != 0)
return [Target(len(state.x_points), target)]
@dataclasses.dataclass(frozen=True)
class Diverted(AbstractTarget):
"""Target for whether the plasma is diverted by an x-point."""
diverted: Optional[shape.Diverted] = None
@property
def outputs(self) -> int:
return 1
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.diverted is not None:
target = self.diverted
else:
target = shape.Diverted.from_refs(references)
actual = 1 if state.is_diverted_d[0] else 0
if target == shape.Diverted.ANY:
return [Target.invalid()] # Don't care.
elif target == shape.Diverted.DIVERTED:
return [Target(actual, 1)]
return [Target(actual, 0)]
@dataclasses.dataclass(frozen=True)
class LimitPoint(AbstractPointsTarget):
"""Target for where the plasma is limited, either on the wall or x-point."""
ref_name: str = dataclasses.field(default="limit_point", init=False)
num_points: int = dataclasses.field(default=1, init=False)
diverted: Optional[shape.Diverted] = None
max_dist: float = 1
def __call__(
self,
voltages: np.ndarray,
state: fge_state.FGEState,
references: named_array.NamedArray) -> List[Target]:
if self.diverted is not None:
diverted_target = self.diverted
else:
diverted_target = shape.Diverted.from_refs(references)
if diverted_target == shape.Diverted.ANY:
return [Target.invalid()]
target_point = self._target_points(references)[0]
if target_point.r == 0:
return [Target.invalid()]
limit_point = shape.Point(*state.limit_point_d[0])
dist = np.hypot(*(target_point - limit_point))
is_diverted = state.is_diverted_d[0]
if diverted_target == shape.Diverted.DIVERTED:
return [Target((dist if is_diverted else self.max_dist), 0)]
return [Target((dist if not is_diverted else self.max_dist), 0)]