What is interesting about 27*^.2 ? T=: 27*^.2 T 18.715 ":!.18 T 18.714973875118524
(spoiler alert.) What is interesting about T=:27*^.2 ? In IEEE 64-bit floating point calculation, for all y>:T, 1=tanh y (and _1=tanh -y) and T is the smallest number with this property. tanh=: (^ - [EMAIL PROTECTED]) % (^ + [EMAIL PROTECTED]) tanh T 1 1 - tanh T 0 hex =: ([EMAIL PROTECTED]) }. 2&(3!:3) unhex=: (3!:2) @ ((}: 2 (3!:3) 0.5)&,) " 1 hex 1,tanh T 3ff0000000000000 3ff0000000000000 hex T 4032b708872320e2 t=. unhex (}:,hex T),'1' NB. the next smaller number hex t 4032b708872320e1 tanh t 1 1 - tanh t 2.22045e_16 hex tanh t 3feffffffffffffe ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
