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HP 38G: Better than Prime for some Sequences using the built in Sequence App
03-10-2015, 03:05 PM (This post was last modified: 03-10-2015 03:09 PM by Tim Wessman.)
Post: #41
RE: HP 38G: Better than Prime for some Sequences using the built in Sequence App
(03-07-2015 05:29 AM)BruceH Wrote:  It's to do with the use of U1 as the index to U1. I tried setting U2 to be U1(N-1) and making the appropriate substitution and that still fails. Creating a user defined function TT(N)=U1(N-1) and substituting also fails. So I think the Sequence app is scanning the parse tree in an effort to avoid a recursive loop and is rejecting cases that would actually work.

Something like this is indeed the issue. The other is that the application was originally implemented by individuals who had basically never touched a calculator (of any type) in their lives. Having something that didn't match exactly U<#>(N),U<#>(N-1), or U<#>(N-2) on parse time meant that it would be blocked.

Anyway, I would appreciate if anyone interested can provide more sequences or tests you'd like me to get into our test plans.

The one that started this thread has been added ( TEVAL(U1(99)) --> .056_s), but I'd appreciate more from interested parties. Honestly, the sequence application hasn't been touched primarily because we've had basically zero feedback from anyone on it (apart from this and the "start at 0" complaint). Most educators don't tend to teach sequences in many places. Most users never touch it either. :-|

I know before I started working for HP I'd never really once touched sequences in earlier calculators or any classes.

TW

Although I work for the HP calculator group, the views and opinions I post here are my own.
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03-10-2015, 04:30 PM
Post: #42
RE: HP 38G: Better than Prime for some Sequences using the built in Sequence App
(03-10-2015 03:05 PM)Tim Wessman Wrote:  
(03-07-2015 05:29 AM)BruceH Wrote:  It's to do with the use of U1 as the index to U1. I tried setting U2 to be U1(N-1) and making the appropriate substitution and that still fails. Creating a user defined function TT(N)=U1(N-1) and substituting also fails. So I think the Sequence app is scanning the parse tree in an effort to avoid a recursive loop and is rejecting cases that would actually work.

Something like this is indeed the issue. The other is that the application was originally implemented by individuals who had basically never touched a calculator (of any type) in their lives. Having something that didn't match exactly U<#>(N),U<#>(N-1), or U<#>(N-2) on parse time meant that it would be blocked.

Anyway, I would appreciate if anyone interested can provide more sequences or tests you'd like me to get into our test plans.

The one that started this thread has been added ( TEVAL(U1(99)) --> .056_s), but I'd appreciate more from interested parties. Honestly, the sequence application hasn't been touched primarily because we've had basically zero feedback from anyone on it (apart from this and the "start at 0" complaint). Most educators don't tend to teach sequences in many places. Most users never touch it either. :-|

I know before I started working for HP I'd never really once touched sequences in earlier calculators or any classes.

Find the people responsible for the 38G sequence implementation - it hasn't failed me so far (c 19 years of use).

The Sequence App is the sole redeeming feature of the 38G.

Except for the second, which is that the machine still works as well as when new.
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08-04-2017, 11:14 AM
Post: #43
RE: HP 38G: Better than Prime for some Sequences using the built in Sequence App
The fault caused by the symbolics in post #1 has now been corrected & the sequence works in the Prime. Please see

http://www.hpmuseum.org/forum/thread-876...l#pid76825

Well done HP!
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