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Praktikum is a formula based program for processing numerical series. It
does not work in a matrix representation mode in the way spreadsheet programs
do, but all the given data are stored within named variables and referred to
by these names in the formulae. Here a variable can be a whole series of data
from an experiment or it can be defined as a formula depending on other
variables. The variables can then be presented either in tables or in
graphs.
Praktikum's advantages show especially when a formula is used many times with
different entries, be this in a parallel way to process a whole series of
data or to form tables of functions, or in a serial way, when parameters are
used in a calculation (e.g. to show the dependence of a function on a certain
parameter, multiple repeating of experiments under varying conditions).
A
simple example: Different resistors are placed in an electrical circuit and
the voltage over the resistors is measured. Now you can put the values of
resistance into a variable r, the voltages into a variable u and you can
define a formula type variable i as u/r. This evaluates as a series of
numbers, yielding the according currents. Praktikum keeps the definition of
i, therefore its value is changed with any change of r or u
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- Data series are stored within named variables which makes Praktikum optimal for
scientific purposes.
- You can optionally assign error ranges to each variable.
- For each formula type variable an automatic symbolic error calculation is
available in accordance with the error propagation law, as far as applicable.
- Advanced operations such as linear regression, symbolic derivation or
Fourier transforms (FFT, frequency analysis and synthesis) are possible.
- Symbolic simplifications of formulae can be activated (useful especially
for symbolic error calculation).
- After changing variables, all output windows, including those of
indirectly dependent variables, are automatically updated.
- Powerful diagram creation routines are included (see
below).
- You can import data:
- Data series as CSV files,
- Formulae as text files (e.g. from within specialised mathematical
applications).
- You can export data:
- Formatted tables as CSV, TSV or TeX files (also see below),
- Formulae (including automatically generated ones) as TeX source code or
as text files,
- Graphs as Draw files.
- The program is completely RISC OS and WIMP compliant: it is multi-tasking
and window oriented; interactive help is supported.
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Praktikum will run on every Acorn computer with RISC OS 3.1 or newer. That
means, it does run even with the following configurations:
- old, but upgraded, machines (A310, A3000),
- machines with only 1MB of memory*,
- machines without a harddisc,
- the new RiscPC.
The speed is acceptable even on ARM 2 machines if you do not require to
process lists of more than some thousand numbers (which correlates to typical
half a minute processing time). On the other side, Praktikum will make use of
a FPA co-processor, if installed, with a drastic increase of speed.
*Please note that Praktikum does not use something like virtual memory, i.e.
all project files must fit into memory. The application itself takes
320kBytes of memory.
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When displaying results of an experiment in tables, it is important that they
are given with the correct number of significant figures or, if an error
range has been computed, with the correct precision according to the error
range, which may be different for each single value. The normal fixed
precision output is inadequate for this purpose. Praktikum does generate
tables like the following*:
You can change the number of significant figures (2 by standard and in the
above example) and the extracted exponent for each variable.
*This document is written using TechWriter. The table has been exported as a
CSV file and format informations such as borders were added. If you use TeX
for setting the table, this is done automatically and the decimal points will
be aligned.
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Praktikum can generate the following types of graphs:
- Line graphs, either straight lines from point to point or interpolating
curves (cubic splines).
- Marker graphs; different markers and size can be chosen:
- Error bars: for each point two bars are generated, showing the uncertainty.
All graphs belong to a co-ordinate system that determines the scaling of the
graph. Each axis can be normal (linear) or logarithmic. On the graphic side,
Praktikum can generate quite a variety of co-ordinate systems:
Normal staves (here: no subdivision)
Whole lines (here: 2 subdivisions per main division and 5 second
subdivisions per subdivision)
Logarithmic axes
More than one graph can be placed in one co-ordinate system and more than one
co-ordinate system can be generated in one diagram; the colours of all graphs
and co-ordinate systems can be selected separately.
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If you are still in doubt, why don't you get a demo version of
Praktikum by clicking on the icon below? This is a
working version; only the saving and export/import functions
have been disabled.
Free Praktikum version (334786 bytes).
You need a ZIP decoder (e.g.
SparkPlug2) to decode the archive.
Probably, to make the best out of the demo version, you'll like to have
a kind of manual. For that reason, we provide an online version of the Praktikum manual here. It was generated from the original manual using TechWriter's excellent HTML export facility. Please note, however, that the manual was written before that feature was introduced into TechWriter, so the document is not as good as it would be if it were written with HTML in mind.
For more details, contact
Feldner & Braun GdbR
Plinganserstraße 49
81369 München
Germany
Phone: +49 921 4 74 63
Email: info@flying-snail.de
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(c) 1997 Feldner & Braun Software GdbR
Many thanks to Acorn Computers Ltd. for designing the first version of
this document.
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