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Readme file for Trace v1.0
Trace is an OPL plotting program which is intended to add to the Psion 3a
the graphical features that are surprisingly missing in the built-in
calculator. Trace is a freeware, so you can use it and distribute it freely.
To install it, just drop the Trace.opa file in the \APP directory and install
in the system as usual. Created dumps or bitmaps files will appear in \OPD.
Trace occupies 13 Kb of disk space, and requires a minimum of 25Kb of RAM.
If you find it useful, please let me know at the following e-mail address:
perroud@messv1.univ-pau.fr.
Trace was developped on a french version of the Psion 3a system, and is
"speaking" french. It has not be tested on other versions. I decided to
keep its native language to emphasize the existence of non-english users
and fans of this marvelous little thing. I think that even non french-
speaking Psion users can easily take advantadge of it. If this is not the
case, I may consider to translate it into an english version, so let me
know your feelings through my e-mail address.
Trace can plot either mathematical functions or 2D data stored in a text file,
or combinations of both types of graphs. The functions are input from the
keyboard, and can use only OPL valid expressions, since the actual calculation
is done through OPL eval() function. When entering the function, each occurence
of the variable (say x) should be replaced by a pair of brackets (). The
function is evaluated at regular intervals, according to the value of xmin,
xmax and the number of points. Predefined defaults value are 51 points between
x=0 and x=1. These values can be changed through the Axes and Options menus.
The datafiles should be text files organized in tab separated columns,
containing pairs of x and y values. The file can consisted of more than two
columns; when entering the data, the column number can be choosen for x and y.
There is no requirements on the order of the data columns. When reading the
file, xmin and xmax are automatically set to the actual limits of the data.
Trace proposes 5 types of graphs, which correspond to the 5 items of the
first menu (Trac‰):
- Trac‰ fonction: allows to plot a function entered at the keyboard with
the preset x range and number of points.
- Trac‰ donn‰es: allows to plot a 2D datafile with symbols and connecting
lines if desired.
- Mod•le num‰rique: allows to plot together a datafile and a model curve
given by a set of x-y pairs in a second text file. The format of the model
text file is the same as the format of the datafile. The x range of the
plot is set by the x range of the datafile, whatever the x range of the
model file.
- Mod•le analytique: allows to plot together a datafile and a model curve
given as a function and entered at the keyboard in the same manner as the
simple function. In that case, the function is evaluated in the x interval
defined by the datafile.
- Fit polynome: allows to plot together a datafile and a model curve given
by the best fit polynomial function, calculated by a least-squares method.
The degree of the polynom can be fixed between 1 (linear fit) and a maximum
of 6 (limited for performance considerations). Once calculated, the best fit
function is proposed as the default function in the other function plots.
Apart from the plots, Trace proposes a few other utilities, like saving the
plot in a PIC file, saving the values calculated for the functions in a text
file, or getting from the screen the x-y coordinates of any point. This last
feature is available only after a plot has been done, and is started by the
diamond key. A cursor is displayed and can be moved with the arrows. The
increment of motion can be adjusted by the psion-arrows combinations. When
the cursor is positionned, the x-y coordinates are displayed by the enter
key. The esc key allows to cancel the operation.
A limited help is available on line using the Help key, or the Aide item of
the Special menu. An abridged version of this file is then displayed. When
the diamond feature is active, short help messages are also displayed when
using the Help key.
Plot options:
Trace will produce a new plot each time you select one of the 5 items of the
Trac‰ menu. In each dialog, previous choices will be offered as defaults, or
predefined values for the first plot. The plot will then be achieved using
the current values of the graphical parameters. If you want to change these
parameters, use the corresponding menu items described below, and then redo
the plot from the menu or its keyboard shortcut.
- Axes menu items:
* Type: allows to change each axis from linear (default) to logarithmic.
* Bornes auto: When set, the y range is automatically adjusted (default).
* Borne x: allows to specify the x range of the plot (default 0-1).
* Borne y: allows to specify the y range of the plot (default automatic).
- Options menu items:
* Nb points: allows to specify the number of points where the functions
will be calculated (default 51). The time required to produce a plot is
very dependant of that parameter. It was therefore limited to 1001.
* Zoom: allows to zoom in a portion of a plot. This option requires a
plot has already been made. When you select it, you have to choose on the
screen the lower left and upper right corners of the rectangle you want to
zoom in. Move the cursor to the first corner, hit enter, then move to the
second corner and enter again. The rectangle will be drawn and you are
asked for confirmation. If you confirm, the last plot will be redone.
* Preferences: allows to change some graphical parameters, including the
size of the plot, size of symbols, connecting lines or the number of
decimals in the axes labels. You have also the possibility to ask for
dumping the x-y pairs calculated for the functions plots in a text file
whose name will be trace.txt. The format of the file allows to replot it
as a datafile, what can save the time necessary to recompute these values.
* D‰fauts: switch back all parameters to their built-in default values.
- Special menu items:
* Info: displays the current values of the graphical parameters.
* Aide: displays a short description of Trace main features.
* Sauve plot: dumps the current plot in a bitmap file (trace.pic).
* Quitte: quit Trace.