desc.magnetic_fields.FourierCurrentPotentialField.from_values
- classmethod FourierCurrentPotentialField.from_values(coords, theta, zeta=None, M=6, N=6, NFP=1, sym=True, check_orientation=True, rcond=None, w=None)Source
Create a surface from given R,Z coordinates in real space.
- Parameters:
coords (array-like shape(num_points,3) or Grid) – cylindrical coordinates (R,phi,Z) to fit as a FourierRZToroidalSurface
theta (ndarray, shape(num_points,)) – Locations in poloidal angle theta where real space coordinates are given. Expects same number of angles as coords (num_points), This determines the poloidal angle for the resulting surface.
zeta (ndarray, shape(num_points,)) – Locations in toroidal angle zeta where real space coordinates are given. Expects same number of angles as coords (num_points), This determines the toroidal angle for the resulting surface. if None, defaults to assuming the toroidal angle is the cylindrical phi and so sets zeta = phi = coords[:,1]
M (int) – poloidal resolution of basis used to fit surface with. It is recommended to fit with M < num_theta points per toroidal plane, i.e. if num_points = num_theta*num_zeta , then want to ensure M < num_theta
N (int) – toroidal resolution of basis used to fit surface with It is recommended to fit with N < num_zeta points per poloidal plane. i.e. if num_points = num_theta*num_zeta , then want to ensure N < num_zeta
NFP (int) – number of toroidal field periods for surface
sym (bool) – True if surface is stellarator-symmetric
check_orientation (bool) – whether to check left-handedness of coordinates and flip if necessary.
rcond (float) – Relative condition number of the fit. Singular values smaller than this relative to the largest singular value will be ignored. The default value is len(x)*eps, where eps is the relative precision of the float type, about 2e-16 in most cases.
w (array-like, shape(num_points,)) – Weights to apply to the sample coordinates. For gaussian uncertainties, use 1/sigma (not 1/sigma**2).
- Returns:
surface (FourierRZToroidalSurface) – Surface with Fourier coefficients fitted from input coords.