I am wondering if anybody here knows which algorithms are used to calculate the inverses of upper tails in the 21s, this is nearly as fast as the 49g+ so I believe the results are not done by a solver.

I know such algorithms exist as I tried to use them when I rewrote STAT48 for the 48G, however it was from a Russian book and I could not figure them out completely.

The 21S manual refers to D. Knuth, Seminumerical Algorihms, Vol. 2, London: Addison Wesley, 1981 for the random number generator test. There may be something in there?

If anyone knows of fast algorithms to get the inverse of upper tails (other than normal distribution which I already have), I would be very interested.

Thanks,

Arnaud