From: b645zjo@utarlg.uta.edu (Rick Homard)
Subject: Re: Hp48 and TI85 compared
NewsSoftware: VAX/VMS VNEWS 1.41    
    <1992Aug20.023308.6024@unixg.ubc.ca>
Organization: The University of Texas at Arlington
NntpPostingHost: utarlg.uta.edu
MessageID: <20AUG199216554888@utarlg.uta.edu>
Date: Thu, 20 Aug 1992 21:55:00 GMT
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In article <1992Aug20.023308.6024@unixg.ubc.ca>, ochealth@unixg.ubc.ca (ochealth) writes...

>>The TI85 supports all boolean operators.  In addition there are commands
>>which:  rotate/shift right/left by one bit and conversion between bases.
>>
>>The HP48 supports all boolean operators, rotate/shift right/left of one
>>bit/byte, setting wordsize, 1 bit arithmetic shift right.
> 
>in case of confusion, the HP48 does support base conversion. (as long as
>it is binary, octal, decimal, or hex) Does the TI85 do arbitrary bases?
> 

I assumed that was a given.  Indeed, the TI85 does support base conversion
for the standard bases (ie: binary, octal, hex, and decimal).



>>
>>
>>Solve Applications
>>
>>Both machines have solve applications.  There is an unusual limitation
>>on the TI85 solve application.  It cannot find complex solutions,
>>only real solutions.  Not good.
> 
>Incorrect! The HP48 solver application can't find complex solutions. If
>an equation has a simple linear/quadratic form, you can use ISOL to find
>complex solutions
> 

I stand corrected on the HP48 not being able to find complex solutions.
I never tried it out and assumed it could.  (Never assume because...)



>>Plotting and Graphing
>>
>>The TI85 plots a bit faster than the HP48.
>>The TI85 has better and more zooming features.
> 
>hmm, this needs explaining? How is one zoom better? How many ways can you
>zoom and pan anyway?
>>

The boxed zooming is better because it creates a box for you to expand
or compress so you can see exactly what you want to zoom in.  Whereas
the HP48 requires two opposite corners...and no box is explicitly drawn.

There is also a feature which allows you to regraph the equation(s)
using the previous range.  This is nice if you want to zoom in on
a different area.

Here are all of the zooming commands:
Box	explained above
Zin	zoom in according to the "zoom factor" (ie: x2, x3,...)
Zout	zoom out 
Zstd	standard graphing range.
Zprev	regraphs equation(s) using the previous range.
Zfit	same as AUTO on HP48.  automatically finds suitable x,y ranges
	to fit the graph on the screen.
Zsqr	set aspect ratio to one.
Ztrig	set built in trig range variables (ie: x axis is divided into
        pi/24 increments.
Zdecm	sets x axis to .1 increments.
Zrcl	displays the range
Zfact	displays the multipling factors for Zin and Zout
ZoomX	zoom in the x axis and leave the y axis alone
ZoomY	zoom in the y axis and leave the x axis alone
Zint	sets x axis to integer value increments
Zsto	sets the user defined range values to the current values.

Other features in the graphic environment:
DIST	finds the distance between two graph points.
ARC	finds the length of an arc given two points.
TANLN	draws a tangent line at any point on a curve.



>>Unit Management
>>
>>Not supported on the TI85.
> 
>I assume this means you can't define your own? Can you perform arithmetic
>with units?
>>
TI doesn't call them units. Rather it is just simple conversion between
units.  
And yes you can define your own unit conversions.



>>Misc
>>
>>The TI85 can solve simultaneous equations (30 unknown maximum).  Indeed
>>the HP48 can do this also but it does not have a user interface to do it
>>from.  A nice feature but slow when solving anything larger than 15 unknowns.
> 
>Simultaneous Linear equations? The HP48 can solve these, and more that 30 too.
>(assuming memory permits)
>>
No doubt but if you are doing work of this magnitude, you really need to
use at least a personal computer

>>I compared the TI85's root finder with the HP48 (using the root finding
>>program supplied by Bill Wickes on the net).  The results are incredible.
>>The same 30th order polynomial was input to each machine.  The HP48 found
>>all of the roots in 80 seconds.  I stopped the TI85 after 15 minutes.
>>It is obvious that the TI85 gets heavily labored when required to perform
>>at its limits.
> 
>Can the TI85 find roots of complex polynomials? Wickes can't, but with a
>little trick (any Wayne`s POLY utils) it can.
>>

The TI85 can find roots of complex polynomials.  I just tried it and
it does work like a charm.


>>The TI85 has an interpolation environment.  You provide two known pairs
>>of data ( (x1,y1) and (x2,y2) )  and one known, either x or y and it will
>>calculate the unknown.
> 
>This has an equivalent in the STATs menu. (with linear regression)
>>

You are correct.  However, I was just stating that this was a feature. 


>>The TI85 performs some fudging (rounding, et al) on calculations.
>>
>>Examples:
>>
>>0.333333333333 * 3 = 1
>>and
>>sin (3.14159265359) = 0
> 
>If I remember TI, they don't really round the answer, they just display
>part of the answer (ie the first 12 digits, and the 13 and 14 are kept
>internally). Sort of like the HP with 10 FIX on all the time, but trailing
>zeros aren't displayed.

This is still "fudging" notheless.  Regardless of how many decimal places
you take .33333333 , when you multiply it by 3 you get .999999999 to the
same number of decimal places.
Also sin(3.14159265359) is a small number but not zero.  The sin(pi)
is zero but 3.14159265359 is not pi.

>>The TI85 also performs numerical integration and differentiation in the
>>graphical environment.
> 
>How fast is it? Does it return an error estimate? I had a TI56 that did
>Simpson's rule, and it was SLOW. When it finished you had NO CLUE whether
>the answer is meaningful. The HP uses an adaptive algorithm which will
>usually return usefull results to an integral, and give you a good idea
>whether the numerical result is close, or way off.

It is fast and it returns an error estimate in a variable, just like
the HP48.  As what method it uses I do not know.



>Is there any way to "get inside" the TI85? I mean software wise. A lot
>of power in the HP48 comes from being able to add low level machine language
>programs that blow away any user level program. For example, the recent ML
>FFT is blindingly fast, and it can't be done quickly in user code.
> 
I do not know.  I have only had it for about a week now.



That's all.

Rick Homard

Newsgroups: comp.sys.hp48,alt.security