dan@Apple.COM (Dan Allen) (03/13/90)
A few miscellaneous notes... UBASE - I believe UBASE has a bug in it. It always rounds fractional unit powers to the nearest integer. For most "normal" units it will not bite you, but it did me when dealing with various geometricized units used in general relativity... All of the arithmetic operations seem to preserve the powers of units fine. It is only when using the UBASE command that this will occur. Example: 1_m^1.5 UBASE --->> 1_m, which is wrong. ABORT - There is no ABORT command in the HP-48SX, as there was in the HP-28. However, KILL works the same. VAR - The HP-48SX supports the statistical variance function, but it is nowhere documented in the manual, but like the HP-28, it is there and works fine. BYTES - Does a good job as a hash function. RND and TRNC - These are about the only functions which operate on every element of a matrix (array); most other functions (like SIN, LN, etc.) will only return an error if given a matrix. TAYLR - Improved from 28S, as it returns denominators with their factorial arguments unexpanded, i.e., 1/3!+1/5! instead of 1/6 + 1/120. EVAL or ->NUM will coelesce the terms if needed. 0^0 = 1 - This is a nice improvement. Most HP calculators have always made 0^0 an error, but Don Knuth and W. Kahan have both persuasively argued that 0^0 should be 1, which it is. Nice! (It makes number theory stuff work right.) Dan Allen Apple Computer
charliep@hpcvra.CV.HP.COM (Charles Patton) (03/14/90)
The ABORT command on the HP28 was replaced with a more generic
version on the HP48. The new command is DOERROR, which allows
the user to "throw" to the nearest trap with any error number
("tag") of their choosing. ABORT is entirely equivalent to
0 DOERROR. The combination of IFERROR...END together with
<non-system-error-number> DOERROR allows generic throw and
catch mechanisms to be used at the user-programming level. It
should be useful to anyone who has ever wanted to break out
of a FOR...NEXT loop, or use other non-local exiting constructs.
...Charlie Patton