Hi Kevin,
As with most software systems, yes there are some very real limitations you
need to be aware of if you are working with large numbers.
There is a native limit you will hit as UniData converts the number to a double
and eventually will lose precision. If working with something like a FOR LOOP,
the engine will use a signed 32-bit number which will wrap around to the
negative.
For my UniData 7.3 on Windows, I cannot correctly increment beyond
9007199254740992 natively (doing X+=1).
To get around this there are a series of functions built upon string math you
will need to use (SADD, SCMP, SMUL, etc). Their limitations are huge (being
more based on memory bounds than C data-type bounds); I doubt you will
realistically hit them.
Regards,
Dan McGrath
PROGRAM BOUND.TEST
CRT @(-1)
* Limit is 9007199254740992
X = 9007199254740000
Y = X
LOOP
X = 1
Y = SADD(Y, 1)
IF Y[LEN(Y)-2,3] = "000" THEN CRT @(-1):X
IF SCMP(X,Y) # 0 THEN CRT "Limit found: {":X:"} vs {":Y:"}";STOP
REPEAT
-----Original Message-----
From: u2-users-boun...@listserver.u2ug.org
[mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Kevin King
Sent: Tuesday, July 10, 2012 1:03 PM
To: U2 Users List
Subject: [U2] Unidata Limits
I was asked a question today that ... well, it stumped me. Is there a
practical limit to an incrementing number on Unidata and if so, what is that
limit? I seem to recall something way back on Reality that said that numbers
could count to 1+e38 or something ridiculous like that, but is that still
applicable?
-K
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