desc.basis.FourierSeries

class desc.basis.FourierSeries(N, NFP=1, sym=False)Source

1D basis set for use with the magnetic axis.

Fourier series in the toroidal coordinate.

Parameters:

• N (int) – Maximum toroidal resolution.

• NFP (int) – number of field periods

• sym ({'cos', 'sin', 'no n0', False}) –

  • 'cos' for cos(n*z) symmetry

  • 'sin' for sin(n*z) symmetry

  • 'no n=0' for no n=0 mode

  • False for no symmetry (Default)

Methods

change_resolution(N[, NFP, sym])	Change resolution of the basis to the given resolutions.
copy([deepcopy])	Return a (deep)copy of this object.
equiv(other)	Compare equivalence between DESC objects.
evaluate(grid[, derivatives, modes])	Evaluate basis functions at specified nodes.
get_idx([L, M, N, error])	Get the index of the 'modes' array corresponding to given mode numbers.
load(load_from[, file_format])	Initialize from file.
save(file_name[, file_format, file_mode])	Save the object.

Attributes

L	Maximum radial resolution.
M	Maximum poloidal resolution.
N	Maximum toroidal resolution.
NFP	Number of field periods.
fft_poloidal	whether this basis is compatible with fft in the poloidal direction.
fft_toroidal	whether this basis is compatible with fft in the toroidal direction.
inverse_LM_idx	Indices of unique_LM_idx that recover the LM mode pairs.
inverse_L_idx	Indices of unique_L_idx that recover the radial modes.
inverse_M_idx	Indices of unique_M_idx that recover the poloidal modes.
inverse_N_idx	Indices of unique_N_idx that recover the toroidal modes.
modes	Mode numbers [l,m,n].
num_modes	Total number of modes in the spectral basis.
spectral_indexing	Type of indexing used for the spectral basis.
sym	Type of symmetry.
unique_LM_idx	Indices of unique radial/poloidal mode pairs.
unique_L_idx	Indices of unique radial modes.
unique_M_idx	Indices of unique poloidal modes.
unique_N_idx	Indices of unique toroidal modes.