pub fn gauss_kronrod_21_rule(a: f64, b: f64) -> [(f64, f64, f64); 21]Expand description
The ten-point Gauss and twenty-one-point Kronrod pair on [a, b]: each
node with its Kronrod weight and its Gauss weight.
The first ten are the nodes of gauss_legendre_rule, in its order and
with its weights as their Gauss weights; the last eleven are the nodes
the Kronrod rule adds, whose Gauss weight is zero. The Kronrod rule is
exact for polynomials up to degree thirty-one, the Gauss rule up to
nineteen, and the gap between the two sums is the usual estimate of
what the Gauss sum still misses. The weights carry the sign of b - a.