From: b645zjo@utarlg.uta.edu (Rick Homard)
Subject: TI85 and HP48 compared
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Date: Fri, 14 Aug 1992 20:58:00 GMT
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Hello to all interested in knowing how the TI85 compares with the
HP48.

This is a (non comprehensive) comparison of the HP48S and the TI85
available features and commands.

==========================================================================

Due to the way both machines are designed and how they operate here are
some 'obvious' differences.

Because the HP48 supports a stack and the TI85 does not, all commands
pertaining to stack manipulation or decomposing objects on the stack
on the HP48 will not have an equivalent on the TI85.

The HP48 supports symbolic algebra and the TI85 does not.
Therefore all commands pertaining to algebraic manipulation will not
have an equivalent on the TI85.

The TI85 does not support a printer and the HP48 does.

Also the HP48 supports customization by allowing the user to make key
assignments.  The TI85 does not support this feature, although you can
assign an "object" to a CUSTOM menu limited to 15 entries...much like
the HP42S.

Although the TI85 does support I/O via a phonojack interface and at one
baud rate, it does not have the rich set of instructions which the HP48
possesses.  I do not know if you can edit the downloaded objects on a
PC or develop a program on a PC and download it to the TI85.  The
interface has not been put on the market yet.  Although a phonojack
interface cable is supplied with each TI85 to interface two TI85
together.

The HP48 supports a clock and the TI85 does not.

The HP48 supports flags and the TI85 does not.


Character Strings

The TI85 only supports the commands which finds the size of a string,
substitutes a portion of a string, and conversion of an equation to a
string and visa versa.

The HP48 supports additional commands like:
AND, OR, XOR, POS, REPL, NUM, NOT, CHR, and concatenation of strings.

Computer Math

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.



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.
The TI85 has the graphing commands also available in the SOLVE environment.


Hyperbolics and Logarithmic Functions

Both machines support the standard hyperbolic and logarithmic functions.
The HP48 supports additional commands which are not on the TI85.
These are: ACOSH, ASINH, ATANH, EXPM, and LNP1


Matrices

The TI85 has *ALL* of the capabilities of the HP48 *PLUS* quite a bit more.
A limitation on the TI85: largest matrix can be 256X256.  But if you are
doing work on a matrix that large, you should be using a math package on
a desk computer (my opinion).

The TI85 can also calculate eignvalues, eignvectors, column norms,
cond    (which returns the condition number of a square matrix),
LU      (which performs lower/upper decomposition on the matrix),
fill    (which stores a value to every element in an existing matrix),
augment (which concatenates two matrices...the rows must be the same size),
randM   (which creates a matrix with random integer (9 to 9) elements).

You can also redimension a matrix with one command.

There are also elementary row operations like:
ref  (returns the row echelon form of a real or complex matrix)
rref (returns the reduced row echelon form of a real/complex matrix)
rSwap (swaps two rows)
rAdd  (adds two rows)
multR (multiplies two rows)
MRAdd (multiply and add row).

For complex matrices there are the commands:
real  (returns a real matrix containing the real portion of each element)
imag  (returns a real matrix containing the complex portion of each element)
abs   (returns a real matrix containing the absolute value of each element)
angle (returns a real matrix containing the polar angle of each element)


Vectors

Both machines support the same commands.


Memory Management

The TI85 does not support directories and the HP48 does; therefore,
the HP48 has a richer set of commands.
The TI85 is limited to finding the amount of RAM memory is free and
a catalog of "objects" to delete.


Plotting and Graphing

The TI85 plots a bit faster than the HP48.

The HP48 supports conic plotting.  The TI85 does not have an equivalent
command although it can be done by plotting the two individual equations
(obviously).
The TI85 supports histogram and scatter plot types.  The HP48 supports
these in addition to barplot and truth plot types.

Both machines support line drawing commands (ie: draw lines, circles,
boxes on a plotted graph).

The TI85 has better and more zooming features.

The TI85 has a DiffEq mode of plotting which allows the user to plot
graphs in terms of "t".


Both machines allow you to save plots.


Program Branching

Both machines support the commands:
IF, THEN, ELSE, END, FOR, REPEAT, WHILE.

The HP48 also supports:
CASE, DO, IFERR, IFT/IFTE, NEXT, START, STEP, UNTIL

The structure of the TI85 is much like that of the old HP41 where you
have GOTOs and RETURNs.


Program Control

Both machines allow you to prompt for input, although the HP48 allows
for more control for input.
Both machines have a "GETKEY" equivalent.
The HP48 supports a debugger.  The TI85 does not have this capability.


Program Test

All the same with the exception of flag testing on the HP48.


Statistics and Probability

The HP48 has the following features over the TI85:

Curve fitting for linear, logarithmic, power, and exponential statistical
models.

Chi square, F test, Normal, Students t test probabilities.


Storage Arithmetic

The TI85 does not support storage arithmetic.

Trigonometric Commands

All the same.

Units

Both machines support unit conversions, although the TI85 does not
support tagged units.

Units for the TI85 are:

Length
mm, cm, m, in, ft, yd, km, mile, nmile, light year, mil, Angstrom,
fermi, rod, fathom

AREA
ft^2, m^2, mi^2, km^2, acre, in^2, cm^2, yd^2, hectare

VOL
liter, gal, qt, pt, oz, cm^3, in^3, ft^3, m^3, cup, tsp, tbsp, ml,
galUK, ozUK
(more than what the HP48 supports)


TIME
sec, mn, hr, day, yr, week, ms, microsec, nanosec

TEMP
C, F, K, R

MASS
gm, kg, lb, amu, slug, ton, mton

FORCE
N, dyne, tonf, kgf, lbf

PRESSURE
atm, bar, N/m^2, mmHg, mmH^2, inHg, inH2O

ENERGY
J, cal, Btu, ft_pd, kw_hr, eV, erg, l_atm

POWER
hp, W, ft_lb/s, Btu/m,

SPEED
ft/s, m/s, mi/hr, km/hr, knot


The HP48 supports all of these (exception of the VOLUME) plus many more.


Unit Management

Not supported on the TI85.



Misc

The TI85 has some features and commands not found on the HP48 (although
they are readily available via Goodies Disks).

The TI85 has:
gcd = greatest common divisor
lcm = least common multiple

=========

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.

============

The TI85 also has a built in polynomial root finder (order =< 30).  A nice
interface but the root finder is terribly slow when the order of the
polynomial is large.
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.

=========

The TI85 can also do sequences of sums or products.  I know that the HP48
can do summation sequences but I don't believe that has the (built in)
capability of doing sequences of products.

========

The TI85 has the "real number to fraction" function as the HP48.  One thing
of difference between the two machines is that the HP48 will make a fraction
regardless if exact or an approximation.  The TI85 will not give a fraction
if it is not exact.

=========

The TI85 has a pEval function.  You give it a list of coefficients from
a polynomial and an argument and it will return the evaluated result.
This is the same thing which can be found in Wayne Scott's polynomial
routines for the HP48.

=========

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.

===========

One very nice feature of the TI85 is the use of lists in equations.
I will give you an example to explain how this works.
If you plot this equation:

{ 1, 2, 3, 4 } SIN (X)

you will get four graphs, one with an amplitude of 1, another with an
amplitude of 2, etc.
This list can be included anyplace in an equation.

=========

The TI85 does not have the commands CEIL and FLOOR.

=========


The TI85 performs some fudging (rounding, et al) on calculations.

Examples:

0.333333333333 * 3 = 1
and
sin (3.14159265359) = 0

==========

The TI85 also performs numerical integration and differentiation in the
graphical environment.

===========

Well that's all I have for now.  If anybody has anything to add please
notify me so I will know as well.


Rick Homard