Piecewise graphing and ifte question

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Zen Rhino

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Jun 16, 2011, 11:56:12 PM6/16/11
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Hi,
Whilst looking for info on graphing piecewise functions (which the TI does effortlessly), I came across this post:

https://groups.google.com/forum/m/#!search/Piecewise$20graph$20HP/comp.sys.hp48/_pGjKJdENIQ

I tried a very simple ifte of ifte(x<0,x^2,sqrt(x))

It stalled fora ew moments and gave me an out of memory error.

I have 187k free in iram and 113k free in eram. Is that truly not enough or is there a bug in the ifte?
I'm using 2.15 which was stock on the unit I purchased in January 2011.

Thanks,

ZR

Bart

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Jun 17, 2011, 9:50:52 AM6/17/11
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On Jun 17, 4:56 am, Zen Rhino <zenrh...@gmail.com> wrote:
> Hi,
> Whilst looking for info on graphing piecewise functions (which the TI does effortlessly), I came across this post:
>
> https://groups.google.com/forum/m/#!search/Piecewise$20graph$20HP/com...

>
> I tried a very simple ifte of ifte(x<0,x^2,sqrt(x))
>
> It stalled fora ew moments and gave me an out of memory error.  
>
> I have 187k free in iram and 113k free in eram. Is that truly not enough or is there a bug in the ifte?
> I'm using 2.15 which was stock on the unit I purchased in January 2011.
>
> Thanks,
>
> ZR


Hi,

try the following:

Define f(X)=IFTE(X<0,X^2,SQRT(X))
(using leftshift-2 (DEF), it will create a variable f that contains <<
-> X 'IFTE(X<0,X^2,SQRT(X))' >> )

create variable g as << 'f(X)' >>

In "Y=' , let Y(X)=g and then DRAW

Regards

hga...@xmission.com

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Jun 17, 2011, 11:33:45 AM6/17/11
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Or use ROM 2.09, which works just fine.

George Litauszky

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Jun 17, 2011, 3:18:45 PM6/17/11
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"<<-> X 'IFTE(X<0,X^2,SQRT(X))' >> )"

Hello,
With this solution can you use the commands of the "FCN" menu on the graph?

Regards

John H Meyers

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Jun 20, 2011, 9:27:02 PM6/20/11
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Re 6/16/2011 10:56 PM:

My input:

'IFTE(X<0,X^2,\v/X)' STEQ ERASE DRAX DRAW PICTURE

Results via Emu48:

HP48GX Rom R:
http://img97.imageshack.us/img97/7477/graph48.jpg [okay]

HP49/50 Rom 2.10 [unreleased but genuine]
http://img109.imageshack.us/img109/4505/graph4950.jpg [error]

On the other hand, after this (with the same HP49/50 ROM):
\<< 'X<0' 'X^2' '\v/X' IFTE \>> STEQ ERASE DRAX DRAW PICTURE

The result is this:
http://img827.imageshack.us/img827/3295/fixed4950.jpg [okay]

In fact, the following also works fine:

\<< 'IFTE(X<0,X^2,\v/X)' \>> STEQ ERASE DRAX DRAW PICTURE

Summary: The algebraic expression 'IFTE(X<0,X^2,\v/X)'
graphs fine on HP49/50 ROM 2.10 if simply enclosed within a program;
otherwise an error occurs.

So there's a simple work-around, without "downgrading" to ROM 2.09,
which, according to another post, eliminates this one error,
at expense of whatever else was corrected in 2.10-2.15
(and your StreamSmart capability, which I'm sure you can't live without :)

[r->] [OFF]

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