Searches the $(n_\mathrm{nodes}, \mathrm{rule}_n)$ configuration space for the fixed Gauss-Legendre rule of minimal total node count whose estimate of $\int F(x) G(x) \mathrm{d}x$ over [xl, xu] matches a high-resolution reference (n_nodes = 1000, rule_n = 7) to within reltol. The selected configuration must additionally reproduce $\int F \mathrm{d}x$ (via

ncm_integral_fixed_nodes_eval) to within reltol — this catches an F feature

narrower than the reference panel width, where the $F\,G$ test alone could false-pass because both reference and trial straddle it. The guard baseline is exact_F_integ when finite, otherwise the reference’s own $\int F$.

This function prepares the NcmIntegralFixed with a grid with n_nodes - 1 intervals beteween xl and xu. In each interval it uses a fixed order (rule_n) Gauss-Legendre integration rule to determine the interval inner points. This results in a grid with (n_nodes - 1) * rule_n points.

This function calculates the nodes of the NcmIntegralFixed. It uses the Gauss-Legendre integration rule to determine the interval inner points.

This function frees the memory associated to NcmIntegralFixed.

Fills nodes with the canonical node abscissae used by

ncm_integral_fixed_calc_nodes, in the same iteration order.

This function evaluates the integral of the function integ->f over the interval [xi, xf] using the nodes calculated by #ncm_integral_fixed_calc_nodes. It uses the Gauss-Legendre integration rule to determine the interval inner points. This function multiplies the integrand by the function F.

This function computes the integral of the function integ->f over the interval starting at max and going to the left using the nodes calculated by #ncm_integral_fixed_calc_nodes. It uses the Gauss-Legendre integration rule to determine the interval inner points. This function multiplies the integrand by the function F. It stops when the relative error is less than reltol.

Computes the integral $\int F(x) G(x) \mathrm{d}x$ as the dot product of the stored quadrature-weighted nodes (which already contain $w_k F(x_k)$) with f_at_nodes (the externally evaluated $G(x_k)$), scaled by delta_x / 2.

This function evaluates the integral of the function integ->f over the interval [xi, xf] using the nodes calculated by #ncm_integral_fixed_calc_nodes.