API Reference

This document provides a detailed API reference for the classes and methods in the em-app package.

solvers.py

This module contains functions for calculating the magnetic field using the Biot-Savart law.

Function	Description	Arguments	Returns
serial_biot_savart	Serial Biot-Savart calculation with element inputs.	element_centers (numpy.ndarray): (N, 3) array of center coordinates. element_lengths (numpy.ndarray): (N,) array of lengths (dl). element_directions (numpy.ndarray): (N, 3) array of unit vectors for current directions. field_points (numpy.ndarray): (M, 3) array of field point coordinates. order (int, optional): Max order of Taylor series. backend (str, optional): Backend to use (‘python’, ‘cpp’, etc.).	numpy.ndarray: (M, 3) array of magnetic field vectors.
mpi_biot_savart	Parallel Biot-Savart calculation using mpi4py.	(Same as serial_biot_savart)	numpy.ndarray or None: On MPI rank 0, an (M, 3) array. On other ranks, None.
numpy_biot_savart	NumPy vectorized Biot-Savart calculation.	(Same as serial_biot_savart)	numpy.ndarray: (M, 3) array of magnetic field vectors.
calculate_b_field	Calculates the magnetic field generated by a coil.	coil_instance (Coil): An instance of a Coil subclass. field_points (np.ndarray): The points where the magnetic field should be calculated. backend (str, optional): The backend to use.	Bfield: A Bfield object containing the calculated magnetic field.

sources.py

This module defines classes for representing different current-carrying coil geometries.

Coil Class

Base class for a current-carrying coil.

Attributes

Attribute	Type	Description
current	float or mtf	The current flowing through the coil.
use_mtf_for_segments	bool	Whether to use MTF for representing the coil segments.
wire_thickness	float	The thickness of the wire in meters.
segment_centers	np.ndarray	Array of the center points of the coil segments.
segment_lengths	np.ndarray	Array of the lengths of the coil segments.
segment_directions	np.ndarray	Array of the direction vectors of the coil segments.

Methods

Method	Description	Returns
get_segments	Returns the discretized segments of the coil.	tuple: (segment_centers, segment_lengths, segment_directions)
get_max_size	Calculates the maximum extent of the coil.	np.ndarray: (3,) array of the maximum size.
get_center_point	Calculates the approximate center point of the coil.	np.ndarray: (3,) array representing the center.
plot	Plots the coil segments in 3D. (Requires matplotlib)	None

RingCoil Class

Represents a circular current-carrying coil. Inherits from Coil.

Attributes

Attribute	Type	Description
radius	float	Radius of the coil.
num_segments	int	Number of segments for discretization.
center_point	np.ndarray	(3,) array for the center coordinates.
axis_direction	np.ndarray	(3,) array for the axis direction.

RectangularCoil Class

Represents a rectangular current-carrying coil. Inherits from Coil.

StraightWire Class

Represents a single straight current-carrying wire. Inherits from Coil.

Attributes

Attribute	Type	Description
start_point	np.ndarray	The starting point of the wire.
end_point	np.ndarray	The ending point of the wire.

plotting.py

This module contains functions for plotting magnetic field data.

Function	Description	Key Arguments
plot_1d_field	Plots a magnetic field component along a 1D line.	coil_instance, field_component, axis, start_point, end_point
plot_2d_field	Plots a magnetic field on a 2D plane.	coil_instance, field_component, plane, center
plot_field_vectors_3d	Generates a 3D quiver plot of the magnetic field vectors.	coil_instance, num_points_a, num_points_b, num_points_c

vector_fields.py

This module defines classes for representing and manipulating vector field data.

Vector Class

A generic class to represent a 3D vector.

Methods

Method	Description	Returns
dot	Calculates the dot product with another Vector.	mtf or float
cross	Calculates the cross product with another Vector.	Vector
norm	Calculates the magnitude (L2-norm) of the vector.	float or mtf
to_numpy_array	Converts the vector to a NumPy array.	np.ndarray

Bvec Class

Represents the magnetic field vector at a point. Inherits from Vector.

Methods

Method	Description	Returns
curl	Calculates the curl of the B-field vector.	Bvec
divergence	Calculates the divergence of the B-field.	mtf
gradient	Calculates the Jacobian matrix of the B-field vector.	np.ndarray (3x3 array of MTFs)

VectorField Class

A class to store a collection of vectors at different points in space.

Attributes

Attribute	Type	Description
vectors	np.ndarray	A NumPy array of Vector objects.
field_points	np.ndarray	A corresponding (N, 3) NumPy array of points.

Methods

Method	Description	Returns
get_magnitude	Calculates the magnitude of each vector.	np.ndarray
to_dataframe	Exports the field to a pandas DataFrame.	pandas.DataFrame