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Kalk 1.0.1 Information Page |
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Introduction |
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KALK is a RPN calculator with statistical computation functions.
You can upload it into your pilot with your install.exe
Application (WinDOS) or with pilot-xfer (Unix) as any
other application. Download kalk101.zip.
(Under UNIX, use unzip -L to uncompress to get lowercase
filenames.)
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Whats new? |
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Bugfix in display handling of engineer mode.
Starting some German documentation.
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General Usage |
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The register you are editing is the 'X' register. One above you
have the 'Y' register. You should remember this to understand
the labels on some of the buttons. For example: y^x means
that you have to type the base and then the exponent. After
pressing ENTER the base will move from the X to the Y register
and the eponent will be entered into the X register afterwards.
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Statistical Functions (German
version) |
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You can enter pairs of numbers into KALK on which it tries to
do linear regression analysis. This means that it tries to find
line which approximates the cloud of points you entered.
- Add
- Adds another pair. If you don't supply a Y value, KALK will
consider this as a zero.
- Delete
- Removes the pair from memory. As KALK does not store statistical
values individually, it is not trivial to remove data once it
has been entered. If you want to delete a value, you can
enter the values again but press Delete instead of Add.
- x,y
- Returns the mean of all X or Y values.
- sx,sy
- Returns the standard deviation (not the variance!)
of all X or Y values. You can compute the variance by pressing
x^2 after sx or sy.
- r
- Returns the "empiric correlation coefficient". Absolute values
close to 1 mean good correlation, values close to 0 mean weak
correlation.
- #
- Returns the number of values you've entered so far.
- bY|X
- Returns the slope of the regression curve when predicting
X for Y.
- bX|Y
- Returns the slope of the regression curve when predicting
Y for X.
If you need the intersection with the ordinate, compute
0 Y->X or X->Y.
- Clear
- Clears all internal statistical registers. Use with caution.
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KALK questions |
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What does KALK mean?
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It's the way Germans procounce calc. Also, it means chalk, an
important tool for matematicans to do calculations :-).
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How to use it?
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Just like a normal RPN calculator.
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What is RPN?
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It means "reverse polish notation". On RPN calculators you have
to type operations after you have typed in all arguments.
Eg: 3 ENTER 4 + instead of 3 + 4. The ENTER is
needed to separate the two arguments.
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Why RPN?
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With RPN you do not need brackets. Moreover, it is much easier
to reuse results from previous computations.
All arguments are being put on the "stack". Whenever you type
an operation, the calculator will get as much arguments as it
needs from the stack and put the result back on the stack.
And, it's much cooler. :-)
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What's a stack?
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A stack is some kind of storage where you can
put things on and get it from in the order "last in - first out".
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When I press ENTER the last entered value has been duplicated!
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The value is not really duplicated because after pressing ENTER
the "stack lock" is on, which means that entering a digit will
not push the number again. The contents of the X register will be
replaced by the new digit.
That's the way my HP 42S behaves. I know that there are other
models - even in HP calculators. But the advantage of this version
is that pressing ENTER twice will push the X register twice
in an intuitive way.
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Kalk prints wrong results!
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The math library I use was originally implemented for
single precision. Using math library functions have
only 5 to 7 digits accuracy whereas basic operations as
adding or division have 15 digits accuracy.
Technical Information:
Copying the math functions and replacing float
by double wouldm't really help as I would have
to figure out new polynomials with more coefficients.
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Limitations |
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- The code size is definitely too large.
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The floating point libraries for math functions
are extremely large. And they don't obey IEEE behaviour!
If someone has a smaller library, please tell me.
- Some illegal operations do not trigger properly.
- This is due to the implementation of the floating point
routines.
- There is no visual marker wether one is using Degree or
Radian
- Stay tuned, its on my to do list. However, you can peek into
the Preferences menu.
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ToDo |
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Finish my thesis.
Fixing Bugs.
Visual marker for angle mode.
Direct key strokes for entering menus or different forms.
Finding a way to reduce the code size.
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Registration |
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This program is postcard-ware, which means that you may copy and
distribute it as far as you like. I won't charge you any fee for this.
But you may not charge anyone for this program either.
If you like KALK, you have to send send a postcard with your email
address (or whatever may serve as some kind of identification) to
Holger Klawitter
Einsteinstr. 62
48149 Muenster
Germany
(eMail reports will be thankfully accepted but do not
count as registraton :-)
If you are a shareware programmer...
... keep in mind that you got my software for free. :-)
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Acknowledgements |
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I would like to thank especially all developers of the Unix-tools
for Pilot software development. Thanks to Wes Cherry, Jeff Dionne,
Kenneth Albanowski,
Ian Goldberg, Scott Grosch, Brian Swetland, and many more and thanks
to USR for supplying the public with the developers handbooks.
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Revision History |
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- 1.0.1 (Jan 25 98)
- Bugfix in display handling of engineer mode.
- 1.0.0 (Aug 11 97)
- Double precision!
- 0.2.2 (Jul 28 97)
- Bugfix in display routines
- 0.2.0 (Jul 21 97)
- More math functions, Registers, Degree support.
- 0.1.3 (June 24 97)
- Several Bugfixes. Smaller Keys.
- 0.1.2 (May 23 97)
- Fixed entering of negative exponents.
- 0.1.1 (May 10 97)
- Documentation improved. (No release change in .prc file)
- 0.1.0 (May 4 97)
- Initial public release.
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Legalese |
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KALK is Copyright (c) 1997-1998 by Holger Klawitter
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose, without fee, and without a written
agreement
is hereby granted, provided that the above copyright notice and this
paragraph and the following two paragraphs appear in all copies.
IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
DOCUMENTATION, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
ON AN "AS IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO
PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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