Wikipedia cites http://icpr.snu.ac.kr/resource/wop.pdf/J01/2002/041/R06/J012002041R060865.pdf,
but seems to differ in in the last decimal of one of the coefficients.
The error is, of course, inconsequential, but it's good to be correct
in any case, and I trust the paper more.
assert(T <= 15000.0f);
if (T <= 4000.0f) {
- x = ((-0.2661239e9 * invT - 0.2343580e6) * invT + 0.8776956e3) * invT + 0.179910;
+ x = ((-0.2661239e9 * invT - 0.2343589e6) * invT + 0.8776956e3) * invT + 0.179910;
} else {
x = ((-3.0258469e9 * invT + 2.1070379e6) * invT + 0.2226347e3) * invT + 0.240390;
}