Function

NumCosmoMathSpectralchebyshev_deriv

Declaration [src]

gdouble
ncm_spectral_chebyshev_deriv (
  GArray* a,
  gdouble t
)

Description [src]

Evaluates the first derivative of a Chebyshev expansion at $t$ using a fused backward recurrence and Clenshaw algorithm, without explicitly forming the derivative series. See the Spectral Methods page for the derivative-coefficient relations.

Parameters

a

Type: An array of double

Chebyshev coefficients array (a_j multiplies T_j).

The data is owned by the caller of the function.
t

Type: gdouble

Point to evaluate in [-1,1].

Return value

Type: gdouble

The value of the derivative at $t$.