Lambert W Function (hp-42s)

[Albert Chan]

Hi, Werner

Very nice complex solver.
Regarding LambertW code, it missed LN before entering solver.
Instead of guess of LN(1.4+X) or LN(X), I found that guess LN(1+X) is simpler.

Here is the revised LambertW (34-byte)

Code:

01▸LBL "W"
02 LSTO "W"
03 "WX"
04 1
05 +
06 LN
07 XEQ "CSLV"
08 RTN
09▸LBL "WX"
10 E↑X
11 LASTX
12 ×
13 RCL- "W"
14 END

Example, i^i^i ... = W(-ln(i))/(-ln(i)) = exp(-W(-ln(i)))

-1
SQRT
LN
+/-
XEQ "W"
+/-
EXP

→ 0.4382829367270321116269751635512648 + 0.3605924718713854859529405269060007i