Frequently Asked Questions About SysQuake
- Q:
What's the graphic in the splash box?
- A:
The logo of SysQuake contains a part of the root locus of a sixth-order system
whose coefficients are contained in an ellipsoid. The sixth-order controller is
chosen for esthetics reasons. The shades of gray correspond to different sizes
of ellipsoids. The root locus was created with the SQ file iupp.sq.
- Q:
Can I use SysQuake to replace other numerical computation software?
- A:
SysQuake is designed for interaction. However, its language, LME, can be used for
any kind of computation. There are two recommended ways to develop your application.
First, you can write new libraries (.lml files) and call their functions from the
command-line interface, which permits you to use variables to store intermediate
results. You have access to graphics, file input/output, extensions, etc.
Second, you can write commands in an SQ script, which has two advantages:
execution starts automatically when you open the file in SysQuake, and you
can change the scale of graphics (SysQuake runs the whole script again to
draw scale-dependent graphics in an optimal way).
- Q: What is _settingFlags?
- A:
Options for the entries of the Settings menu, which are specified by
_enable and _checkmark, are grouped together into
a function named _settingFlags. If an error occurs during the
evaluation of one of the expressions, it is likely to be reported with a
reference to _settingFlags. The line number corresponds to
the number of the menu entry.
- Q: On the Macintosh, the screen blinks when I manipulate a
graphic. Is it normal?
- A:
When it has enough memory, SysQuake uses an internal representation of the
content of the window to draw the figures, and then copies it to the screen.
This prevents the blinking you can see, which results from erasing the window
before drawing an updated figure. On the Macintosh, to give more memory to
SysQuake, make sure that it is not open, select its icon in the Finder (single-click
it), then choose Get Info in the File menu. You can increase the Preferred Size.
A value of 10000 KB (about 10 megabytes) should be enough even for a large window
and millions of colors. If you do not see the field "Preferred Size" and you
have Mac OS 8.5, select Memory in the popup menu in the Info window.
If you cannot edit the size, SysQuake is probably running, or the disk is locked.
SysQuake may also support temporary memory, which adds some flexibility by
using memory not used by Mac OS. See Getting Started
for more details.
- Q: Why does the frequency response disappear at negative
frequencies when a large part of positive is displayed?
- A:
Because of the symmetry, frequency responses are usually displayed only for
positive frequencies. SysQuake leaves a small margin between zero and the left
of the figure. To avoid displaying a peak at low frequency when the frequency
scale is linear, which might be seen as a resonance, negative frequencies are
displayed only when they represent more than 10 % of the total range.
- Q: Why is SysQuake for Windows much larger than SysQuake
for Macintosh?
- A:
While a large part of SysQuake is based on the same source code for Macintosh
and Windows computers, which ensures a very high level of cross-platform compatibility,
simplifies the tests and improves the quality of both versions, the graphical user
interface and the access to the operating system is platform-dependent. On the
Macintosh, this part, written in C, is based directly on Mac OS calls, which
permits efficient coding. On Windows, it is based on a C++ framework, which
simplifies the source code by a large amount (user interface elements such as
toolbars or the mechanism to dispatch user actions are provided almost without
coding), but needs a large library. While it would be possible to include this
code as a shared library (DLL), it is safer to include it in SysQuake itself
to avoid problems when the operating system is updated or other programs are
installed. In addition, the installation process is as simple as dragging SysQuake
or its directory from a cd-rom to your hard disk, and the uninstallation process
as simple as dragging it to the Recycle Bin.
Copyright 1998-2001, Calerga.
All rights reserved.