feat: Adds Random count dipole model with binomial type distribution for dipole number

pdme/model/__init__.py

@@ -3,9 +3,13 @@ from pdme.model.fixed_magnitude_model import SingleDipoleFixedMagnitudeModel
 from pdme.model.multidipole_fixed_magnitude_model import (
 	MultipleDipoleFixedMagnitudeModel,
 )
+from pdme.model.random_count_multidipole_fixed_magnitude_model import (
+	RandomCountMultipleDipoleFixedMagnitudeModel,
+)
 
 __all__ = [
 	"DipoleModel",
 	"SingleDipoleFixedMagnitudeModel",
 	"MultipleDipoleFixedMagnitudeModel",
+	"RandomCountMultipleDipoleFixedMagnitudeModel",
 ]

pdme/model/random_count_multidipole_fixed_magnitude_model.py

@@ -0,0 +1,119 @@
+import numpy
+import numpy.random
+from pdme.model.model import DipoleModel
+from pdme.measurement import (
+	OscillatingDipole,
+	OscillatingDipoleArrangement,
+)
+
+
+class RandomCountMultipleDipoleFixedMagnitudeModel(DipoleModel):
+	"""
+	Model of multiple oscillating dipoles with a fixed magnitude, but free rotation.
+
+	Parameters
+	----------
+	pfixed : float
+	The fixed dipole magnitude.
+
+	n_max : int
+	The maximum number of dipoles.
+
+	prob_occupancy : float
+	The probability of dipole occupancy
+	"""
+
+	def __init__(
+		self,
+		xmin: float,
+		xmax: float,
+		ymin: float,
+		ymax: float,
+		zmin: float,
+		zmax: float,
+		pfixed: float,
+		n_max: int,
+		prob_occupancy: float,
+	) -> None:
+		self.xmin = xmin
+		self.xmax = xmax
+		self.ymin = ymin
+		self.ymax = ymax
+		self.zmin = zmin
+		self.zmax = zmax
+		self.pfixed = pfixed
+		self.rng = numpy.random.default_rng()
+		self.n_max = n_max
+		if prob_occupancy >= 1 or prob_occupancy <= 0:
+			raise ValueError(
+				f"The probability of a dipole site occupancy must be between 0 and 1, got {prob_occupancy}"
+			)
+		self.prob_occupancy = prob_occupancy
+
+	def __repr__(self) -> str:
+		return f"RandomCountMultipleDipoleFixedMagnitudeModel({self.xmin}, {self.xmax}, {self.ymin}, {self.ymax}, {self.zmin}, {self.zmax}, {self.pfixed}, {self.n_max}, {self.prob_occupancy})"
+
+	def get_dipoles(
+		self, max_frequency: float, rng_to_use: numpy.random.Generator = None
+	) -> OscillatingDipoleArrangement:
+		rng: numpy.random.Generator
+		if rng_to_use is None:
+			rng = self.rng
+		else:
+			rng = rng_to_use
+
+		dipoles = []
+
+		n = rng.binomial(self.n_max, self.prob_occupancy)
+
+		for i in range(n):
+			theta = numpy.arccos(rng.uniform(-1, 1))
+			phi = rng.uniform(0, 2 * numpy.pi)
+			px = self.pfixed * numpy.sin(theta) * numpy.cos(phi)
+			py = self.pfixed * numpy.sin(theta) * numpy.sin(phi)
+			pz = self.pfixed * numpy.cos(theta)
+			s_pts = numpy.array(
+				(
+					rng.uniform(self.xmin, self.xmax),
+					rng.uniform(self.ymin, self.ymax),
+					rng.uniform(self.zmin, self.zmax),
+				)
+			)
+			frequency = rng.uniform(0, max_frequency)
+
+			dipoles.append(
+				OscillatingDipole(numpy.array([px, py, pz]), s_pts, frequency)
+			)
+		return OscillatingDipoleArrangement(dipoles)
+
+	def get_monte_carlo_dipole_inputs(
+		self,
+		monte_carlo_n: int,
+		max_frequency: float,
+		rng_to_use: numpy.random.Generator = None,
+	) -> numpy.ndarray:
+
+		rng: numpy.random.Generator
+		if rng_to_use is None:
+			rng = self.rng
+		else:
+			rng = rng_to_use
+
+		shape = (monte_carlo_n, self.n_max)
+		theta = 2 * numpy.pi * rng.random(shape)
+		phi = numpy.arccos(2 * rng.random(shape) - 1)
+
+		p_mask = rng.binomial(1, 0.5, shape)
+		p_magnitude = self.pfixed * p_mask
+
+		px = p_magnitude * numpy.cos(theta) * numpy.sin(phi)
+		py = p_magnitude * numpy.sin(theta) * numpy.sin(phi)
+		pz = p_magnitude * numpy.cos(phi)
+
+		sx = rng.uniform(self.xmin, self.xmax, shape)
+		sy = rng.uniform(self.ymin, self.ymax, shape)
+		sz = rng.uniform(self.zmin, self.zmax, shape)
+
+		w = rng.uniform(1, max_frequency, shape)
+
+		return numpy.stack([px, py, pz, sx, sy, sz, w], axis=-1)