Method

NumCosmoMathSpectralcompute_chebyshev_coeffs

Declaration [src]

void
ncm_spectral_compute_chebyshev_coeffs (
  NcmSpectral* spectral,
  NcmSpectralF F,
  gdouble a,
  gdouble b,
  guint order,
  GArray** coeffs,
  gpointer user_data
)

Description [src]

Computes order Chebyshev coefficients of $f(x)$ on $[a,b]$ at fixed resolution, sampling F at the Chebyshev–Lobatto nodes and applying FFTW DCT-I. See the Spectral Methods page for the node placement and coefficient normalization.

If coeffs points to NULL, allocates a new GArray of size order. If coeffs points to an existing GArray, resizes it to order. Through bindings, coeffs always receives NULL.

Parameters

F

Type: NcmSpectralF

Function to evaluate, receives x in [a,b].

a

Type: gdouble

Left endpoint of the interval.

b

Type: gdouble

Right endpoint of the interval.

order

Type: guint

Number of Chebyshev coefficients to compute.

coeffs

Type: An array of double

Output array of coefficients.

The argument will be set by the function.

The caller of the method takes ownership of the returned data, and is responsible for freeing it.

user_data

Type: gpointer

User data for F.

The argument can be NULL.

The data is owned by the caller of the method.