Method

NumCosmoXcorSSCSijset_peak_epsilon

Declaration [src] 

void
nc_xcor_ssc_sij_set_peak_epsilon (
  NcXcorSSCSij* ssc_sij,
  gdouble peak_epsilon
)

Description [src]

Sets the absolute floor of the adaptive refinement building the $U_i(k)$ spline of every kernel. This, not the relative tolerance, is what limits the accuracy of the off-diagonal $S_{ij}$, which are a small residual of a large cancellation: tightening it from NcXcorKernel‘s own 1.0e-4 default to the 1.0e-6 used here moves $S_{06}$ by tens of percent for J-PAS-like bins while barely moving $S_{00}$.

1.0e-6 is the end of that road, not a waypoint. The floor is a fraction of the peak of $W_i(k)$ while the integrand is $k^2 W_i W_j$, so it enters squared: 1.0e-6 is already 1.0e-12 there. Below it nc_xcor_kernel_set_peak_epsilon() warns and the accuracy is not recoverable at any cost — see NC_XCOR_KERNEL_MIN_USEFUL_PEAK_EPSILON.

Sets propertyNumCosmo.XcorSSCSij:peak-epsilon

Parameters

peak_epsilon

Type: gdouble

The absolute floor of the adaptive refinement.