desc.grid.LinearGrid

class desc.grid.LinearGrid(L=None, M=None, N=None, NFP=1, sym=False, axis=True, endpoint=False, rho=None, theta=None, zeta=None)Source

Grid in which the nodes are linearly spaced in each coordinate.

Useful for plotting and other analysis, though not very efficient for using as the solution grid.

Parameters:

• L (int, optional) – Radial grid resolution.

• M (int, optional) – Poloidal grid resolution.

• N (int, optional) – Toroidal grid resolution.

• NFP (int) – Number of field periods (Default = 1). Change this only if your nodes are placed within one field period or should be interpreted as spanning one field period.

• sym (bool) – True for poloidal up/down symmetry, False otherwise. Default is False. Whether to truncate the poloidal domain to [0, π] ⊂ [0, 2π) to take advantage of poloidal up/down symmetry, which is a stronger condition than stellarator symmetry. Still, when stellarator symmetry exists, flux surface integrals and volume integrals are invariant to this truncation.

• axis (bool) – True to include a point at rho=0 (default), False for rho[0] = rho[1]/2.

• endpoint (bool) – If True, theta=0 and zeta=0 are duplicated after a full period. Should be False for use with FFT. (Default = False). This boolean is ignored if an array is given for theta or zeta.

• rho (int or ndarray of float, optional) – Radial coordinates (Default = 1.0). Alternatively, the number of radial coordinates (if an integer). Note that if supplied the values may be reordered in the resulting grid.

• theta (int or ndarray of float, optional) – Poloidal coordinates (Default = 0.0). Alternatively, the number of poloidal coordinates (if an integer). Note that if supplied the values may be reordered in the resulting grid.

• zeta (int or ndarray of float, optional) – Toroidal coordinates (Default = 0.0). Alternatively, the number of toroidal coordinates (if an integer). Note that if supplied the values may be reordered in the resulting grid.

Methods

change_resolution(L, M, N[, NFP])	Change the resolution of the grid.
compress(x[, surface_label])	Return elements of x at indices of unique surface label values.
copy([deepcopy])	Return a (deep)copy of this object.
copy_data_from_other(x, other_grid[, ...])	Copy data x from other_grid to this grid at matching surface label.
equiv(other)	Compare equivalence between DESC objects.
expand(x[, surface_label])	Expand x by duplicating elements to match the grid's pattern.
get_label(label)	Get general label that specifies direction given label.
load(load_from[, file_format])	Initialize from file.
meshgrid_flatten(x, order)	Flatten data to match standard ordering.
meshgrid_reshape(x, order)	Reshape data to match grid coordinates.
replace_at_axis(x, y[, copy])	Replace elements of x with elements of y at the axis of grid.
save(file_name[, file_format, file_mode])	Save the object.

Attributes

L	Radial grid resolution.
M	Poloidal grid resolution.
N	Toroidal grid resolution.
NFP	Number of (toroidal) field periods.
axis	Indices of nodes at magnetic axis.
can_fft2	Whether this grid is compatible with 2D FFT.
coordinates	Coordinates specified by the nodes.
endpoint	Whether the grid is made of open or closed intervals.
fft_poloidal	whether this grid is compatible with fft in the poloidal direction.
fft_toroidal	whether this grid is compatible with fft in the toroidal direction.
inverse_alpha_idx	Indices that recover field line poloidal angles.
inverse_poloidal_idx	Indices that recover the unique poloidal coordinates.
inverse_rho_idx	Indices of unique_rho_idx that recover the rho coordinates.
inverse_theta_PEST_idx	Indices that recover unique straight field line poloidal angles.
inverse_theta_idx	Indices that recover unique theta coordinates.
inverse_zeta_idx	Indices of unique_zeta_idx that recover the zeta coordinates.
is_meshgrid	Whether this grid is a tensor-product grid.
node_pattern	Pattern for placement of nodes in (rho,theta,zeta).
nodes	Node coordinates, in (rho,theta,zeta).
num_alpha	Number of unique field line poloidal angles.
num_nodes	Total number of nodes.
num_poloidal	Number of unique poloidal angle coordinates.
num_rho	Number of unique rho coordinates.
num_theta	Number of unique theta coordinates.
num_theta_PEST	Number of unique straight field line poloidal angles.
num_zeta	Number of unique zeta coordinates.
period	Periodicity of coordinates.
spacing	Quadrature weights for integration over surfaces.
sym	True for poloidal up/down symmetry, False otherwise.
unique_alpha_idx	Indices of unique field line poloidal angles.
unique_poloidal_idx	Indices of unique poloidal angle coordinates.
unique_rho_idx	Indices of unique rho coordinates.
unique_theta_PEST_idx	Indices of unique straight field line poloidal angles.
unique_theta_idx	Indices of unique theta coordinates.
unique_zeta_idx	Indices of unique zeta coordinates.
weights	Weight for each node, either exact quadrature or volume based.