Function
NumCosmoMathSpectralcompute_x_row
Declaration [src]
void
ncm_spectral_compute_x_row (
gdouble* row_data,
glong k,
glong offset,
gdouble coeff
)
Description [src]
Computes row k of the multiplication by x operator that maps Chebyshev coefficients to Gegenbauer $C^{(2)}_k$ coefficients.
Input: Chebyshev $T_n(x)$ basis coefficients (columns) Output: Gegenbauer $C^{(2)}_k(x)$ basis coefficient for $x \cdot f(x)$ (row k)
Adds to existing row data (for linear combinations of operators).
Matrix entries for row k: - If k >= 1: column k-1: coeff * 1/(4(k+1)) - column k+1: coeff * -1/(4(k+3)) - column k+3: coeff * -1/(4(k+1)) - column k+5: coeff * 1/(4(k+3)) - For k=0 only: additional value coeff * 1/4 at column 1 - For k=1 only: additional value coeff * 1/8 at column 0.