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sum list in 17bii solver equation - Printable Version

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sum list in 17bii solver equation - Don Shepherd - 08-13-2007

I don't think this is possible, but is there any way to change the value of a sum list item within a solver equation?


Re: sum list in 17bii solver equation - Vincze - 08-13-2007

I have only played with a 17BII once, but I thought you could navigate though the list with the up and down arrows, and then delete the item and then reenter a new item for the changed value. Actually, I think you can just type over the item value that you wish to change.


Re: sum list in 17bii solver equation - Peter A. Gebhardt - 08-14-2007

Don,

I hope I understand your question correctly - did you try the following snippet?

Quote:
SIGMA(
i:
1:
n:
L(step:<EXPRESSION>):
0*L(variable:G(variable)<OPERATOR> <EXPRESSION> .... )
)

<OPERATOR> == *,/,+,- ...
<EXPRESSION> == any valid expression in the solver context

Best regards,

Peter A. Gebhardt


Re: sum list in 17bii solver equation - Don Shepherd - 08-14-2007

Peter, I should have phrased my request better. By *sum list* I mean a named list associated with the Sum function from the main menu. You know, press Sum and start entering values in the list, and when you are done you can name the list. You can *read* these sum list items with the ITEM function in a solver equation, but you cannot *write* or update them within the solver, at least I have not been able to do that and I have a feeling you cannot do it.

L(ITEM(MYLIST:1):123) does not work.


Re: sum list in 17bii solver equation - bill platt - 08-14-2007

To be able to do that would be way too cool and would border on black magic! :-)


Re: sum list in 17bii solver equation --> 35s solver - Katie Wasserman - 08-14-2007

True you can't do this on the 17bii but you *can* do it on the 35s with the expression fragment: 0x( aaa STO I + bbb STO (I)). aaa is the array index location, yyy is whatever you want to store in that array location. (You can, of course, you J and (J) if you'd like too.)

You can use this to control looping on the 35s too there's more here.


Edited: 14 Aug 2007, 12:25 p.m.


Re: sum list in 17bii solver equation - Peter A. Gebhardt - 08-14-2007

Don,

as Bill Platt already stated - sorry (currently?)not ...

Something Bob McGuire, Tony Hutchins any many other great contributors to this Forum alreday missed very much.

The only hope is, that HP at some future time would bring us a new type of financial calculator with the best of the HP19b/27s Solvers combined with the urgently needed enhancements requested so often already.

What I discovered playing around with the offered code snippet on an 200LX is, that

- loop variable "i" does show up in the custom menu, if used in an expression

- "i" is not the same as L(i, ....), so g(i) to supress it showing up on a custom menu doesn't work - so TWO VARIABLES "i" (or a second "instance" of ANY loop variable), are apparently possible!

Best regards,

Peter A. Gebhardt


Re: sum list in 17bii solver equation --> 35s solver - bill platt - 08-14-2007

Holy cow, how did I miss that thread!

Nice work. When I read about the sto rcl inside the equation list I must admit I was excited too, but I hadn't thought of anything concrete--it was just a feeling like, "now *that* wil be useful!"--and so it is!:-)


Re: sum list in 17bii solver equation - Don Shepherd - 08-14-2007

Peter, you are probably right.

As a programmer, the idea of 2 different variables with the same name makes me just want to go find a tropical island somewhere and get away from it all!

Katie's insights into the 35s solver are nothing short of brilliant. I'm still trying to comprehend it all.