desc.magnetic_fields.MagneticFieldFromUser

class desc.magnetic_fields.MagneticFieldFromUser(fun, params=None)Source

Wrap an arbitrary function for calculating magnetic field in lab coordinates.

Parameters:

• fun (callable) –

  Function to compute magnetic field at arbitrary points. Should have a signature of the form fun(coords, params) -> B where

  • coords is a (n,3) array of positions in R, phi, Z coordinates where the field is to be evaluated.

  • params is an array of optional parameters, eg for optimizing the field.

  • B is the returned value of the magnetic field as a (n,3) array in R, phi, Z coordinates.

• params (ndarray, optional) – Default values for parameters. Defaults to an empty array.

Methods

compute_Bnormal(surface[, eval_grid, ...])	Compute Bnormal from self on the given surface.
compute_magnetic_field(coords[, params, ...])	Compute magnetic field at a set of points.
compute_magnetic_vector_potential(coords[, ...])	Compute magnetic vector potential at a set of points.
copy([deepcopy])	Return a (deep)copy of this object.
equiv(other)	Compare equivalence between DESC objects.
load(load_from[, file_format])	Initialize from file.
pack_params(p)	Convert a dictionary of parameters into a single array.
save(file_name[, file_format, file_mode])	Save the object.
save_BNORM_file(surface, fname[, basis_M, ...])	Create BNORM-style .txt file containing Bnormal Fourier coefficients.
save_mgrid(path, Rmin, Rmax, Zmin, Zmax[, ...])	Save the magnetic field to an mgrid NetCDF file in "raw" format.
unpack_params(x)	Convert a single array of concatenated parameters into a dictionary.

Attributes

dim_x	total number of optimizable parameters.
dimensions	dictionary of integers of sizes of each optimizable parameter.
optimizable_params	string names of parameters that have been declared optimizable.
params	Parameters of the field allowed to vary during optimization.
params_dict	dictionary of arrays of optimizable parameters.
x_idx	arrays of indices for each parameter in concatenated array.