Grace is a tool to make two-dimensional plots of numerical data. It runs under various (if not all) flavours of UNIX with X11 and M*tif. Its capabilities are roughly similar to GUI-based programs like Sigmaplot or Microcal Origin plus script-based tools like gnuplot or Genplot. Its strength lies in the fact that it combines the convenience of a graphical user interface with the power of a scripting language which enables it to do sophisticated calculations or perform automated tasks.
Grace is derived from Xmgr (a.k.a. ACE/gr), originally written by Paul Turner.
From version number 4.00, the development was taken over by a team of volunteers under the coordination of Evgeny Stambulchik.
When its copyright was changed to GPL, the name was changed to Grace, which stands for ``GRaphing, Advanced Computation and Exploration of data'' or ``Grace Revamps ACE/gr''. The first version of Grace available is named 5.0.0, while the last public version of Xmgr has the version number 4.1.2.
Paul still maintains and develops a non-public version of Xmgr for internal use.
You can get the newest information about Grace and download the latest version at the Grace home page.
You can fetch it from a mirror site as well. The list of mirror sites can be found at ftp://plasma-gate.weizmann.ac.il/pub/grace/MIRRORS.
Please refer to the official Grace Home Page. There you can also find the latest version of this FAQ, links to the latest release and to mirror sites closer to you.
Apart from the licensing, the main difference is that Grace is WYSIWYG (What You See Is What You Get). This was achieved through a major rewrite of all the mid-level drawing routines and the use of the device-independent Type 1 font rendering library T1lib for typesetting.
For help with changing from Xmgr to Grace see section
Xmgr to Grace migration guide in the
User's Guide (question
User's Guide.
There are currently several features of Xmgr which are not yet implemented in Grace (of course, alongside with a lot of new stuff not found in Xmgr). A full compatibility is desirable except for ``bad'' features of Xmgr.
Among the Xmgr features not (yet) implemented in Grace are:
When the licensing was changed to GPL, Paul wanted to keep the name for his non-public version of Xmgr, so we chose a new name.
Yes. Grace is free in terms of the GNU General Public
License (GPL) (see the file LICENSE which comes with
Grace or the
GNU Home Page for details).
The sources of Grace still contain a significant amount of code from
Xmgr by Paul Turner. For a list of those who contributed to Grace
since then, see the file CHANGES in the Grace distribution.
Some integral parts of Grace are borrowed from other packages, namely libraries which are also available as stand-alone distributions. In alphabetical order:
Yes. It is written in SGML which means that all the above
versions can easily be created using sgml-tools (see
their
home page).
At the Grace home page
(see question
Home Page), all
these versions are available.
As of now, Grace is a purely virtual creature living in the net, i.e. there is no printed literature. All relevant docs are currently bundled with Grace. See questions Home Page and User's Guide for details. You can print your own copy of the FAQ, the User's Guide and the Tutorial by converting the DVI files to PostScript output.
Yes. It is part of the Grace distribution and usually is
located in $GRACE_HOME/doc/. There are several
versions: the SGML source and HTML, LaTeX, DVI and PS
derived from it. You can read the HTML version from a
running Grace session by clicking on "Help/User
Guide". You need a web browser to read the HTML version
(see also question
Environment Variables). You can always download the newest version
from the Grace homepage (see question
Home Page).
The User's Guide is not quite complete, yet.
Yes. There are several tutorials which give detailed
step-by-step information how to achieve various tasks. They
are also part of the Grace distribution. You can find them
in $GRACE_HOME/doc/.
There are tutorials about creating a simple plot, batch plotting, fitting curves, transformations (graphical - simple ones, interpolation, feature extraction, using the command line), using pipes, overlaying graphs, hot links.
You have the following options:
$GRACE_HOME/doc/ along with other files which
may contain useful help for your problem. If you
downloaded the sources, there are even more files in
the main directory of the source tree.
No, there isn't. We feel that a bulletin board (see question Forums) is more appropriate to discuss the topics related to Grace.
There used to be a few, but now they are replaced with bulletin-board-style forums (see question Forums).
The mailing list archives are still available for browsing.
Yes. Just follow this link: forums. It has its own FAQ.
Make sure that what you found really is a bug.
Try to make sure that it is a bug in Grace, and that the failure is not caused by another piece of software.
Make sure you are running the latest official release of Grace. The development of Grace is rather fast, so your bug might already be fixed.
Try to find out if the bug is already known (see question Known Bugs).
OK: You have found a new bug. Use w3todo (question Known Bugs) to report it. Follow the instructions on the page and try to be as precise as possible. It won't be of much help if you write ``The program crashes.'' Try to find a simple reproducible case. Mention the version of Grace and where you got the build and the operating system you use. You should submit the system info as provided by ``uname -a'' (if this utility exists, of course) and the output of ``xmgrace -version''. Often the problem is related to some specific data set. Please try hard on reducing this to the minimum which is sufficient of reproducing the bug. If it's only a few lines of data please submit it together with the other details. Once you submit the bug report, it will be automatically relayed to the mailing list. You will usually be notified when the bug is fixed or if we need more information, so please don't forget to give your correct e-mail address.
Yes. You can search and browse the database of known bugs in
Grace at the bug report facility
w3todo
or using the "Help/Comments" menu from within
Grace. The database also keeps track of the status of the
bug (Confirmed, Working on, Testing, Fixed, Closed,
etc.). This is also the place to submit bug reports and
wishes.
Some bugs and fixes may not appear in w3todo, but are covered on the forums.
The term "fixed" means the bug is fixed in the current development version, and the next public version will have the fix in it. Reports with fixes incorporated in an existing public version are marked as "Closed".
You must have missed something very obvious. Check out how to properly submit a bug report in this document. Most probably your report was incomplete or just redundant to an existing entry. It's worth checking the log file of the bug report (the "View log" button at the bottom of the report viewing page).
You can submit wishes and suggestions just the way you would submit bug reports (see question Known Bugs). Suggestions for improvement are generally very welcome. It may be possible, however, that the developers are busy or that your wish is rejected for some good reason, so it may be necessary to persuade (better convince) them to get at it.
Fine! There are always things to do.
If you are a C programmer, you can almost certainly find something useful to do. Just ask on the forums. The same applies if you are a technical writer. The documentation will certainly need to be updated, corrected or completed. Every small contribution is appreciated!
Make Grace known to your friends and colleagues. The more users Grace has, the faster it will be improved.
Prepare diffs against the most recent version. Use either unified (-u) or context (-c) diff format. Specify exactly against which version the diff is supposed to work. Finally send them to mailto:fnevgeny at weizmann dot ac dot il
In case you plan to help this way more than once you should join the forums.
No need to. But if you feel like making a donation, choose any charity organization you like. You wanted to give them some money, anyway, right? ;-)
You have the choice: either you compile the sources yourself or you download precompiled binaries (we strongly suggest you take the first route). You can get both from the Grace Home Page. Whether binaries for your platforms are available (see question Binaries) depends on whether one of the developers has access to the respective platform and has had time to do it.
It is always a good idea to read the READMEs that accompany
the downloading packages of Grace.
Yes! Actually, this is the preferred method of installation.
After getting the sources (question
Installation) and ungzipping and untaring
them (use e.g. gzip -dc grace-5.0.4.tar.gz | tar xvf -),
proceed according to the relevant section of the
User's Guide, which covers the compilation
process.
There are several possible reasons:
libjpeg62 and libjpeg62-devel
packages must be installed.--with-extra-ldpath and
--with-extra-incpath configure options to provide the
extra paths, respectively.Check whether M*tif (question M*tif) is installed on your system. If it is, look at the file config.log: there is a line like this:
configure:8900: checking for a Motif >= 1002 compatible API
What comes directly after it? Could be a hint. Also, see the previous question.
Throughout the Grace docs, saying "M*tif" we actually refer to the Motif API, defining a set of functions for building graphical user interfaces (GUI) via numerous widgets (buttons, labels, etc). Grace makes a heavy use of the M*tif API.
There are several implementations of the interface. The original OSF Motif (see http://www.opengroup.org) recently changed its license: on open-source platforms you may have a chance to use it for free, although it's not in general qualified as either a FreeSource or OpenSource product.
There is, however, a free replacement for Motif called LessTif (see http://www.lesstif.org). LessTif is intended to be a 100% source compatible replacement for Motif, but is still under development. For the purposes of Grace, try using the latest version of LessTif (at least 0.92.6 and above). The LessTif people usually receive many bug reports from the Grace developers, so you might hope that a few remaining bugs in LessTif will be fixed rather quickly.
"ar" is the library archiver (the program used to create static libraries like libFoo.a). You should have it in your path. Under Solaris, for example, this can be found in /usr/ccs/bin.
We do not officially support binary packages. When contributed by volunteers they're put in under the contrib area. Again, these are NOT supported (bug reports like "I can't install that RPM" will be silently ignored), but feel free using the Grace forums for relevant discussions.
Yes, Grace runs on VMS. Just compile it there.
As for Win32 (Windows 95/98/NT/2000/XP) and OS/2, there are ports for these platforms, though they are not "native", i.e. in order to run them, one needs an X server for the respective platform.
Both OS/2 and Win32 ports may lack some of the functionality (notably, support for "direct"/native printing; probably you will have to use the Postscript output for printing).
A port to OS/2 made by Alexander Mai can be found at http://www.tu-darmstadt.de/~st002279/os2/. It requires the XFree86 libraries and an X Server (e.g. XFree86, Hob X11, Exceed, etc.).
If you get such a message at the linkage stage, telling about .LL794 (or similar) unresolved symbols, try compiling with native cc compiler instead (./configure --with-cc=cc).
For certain tasks, Grace needs external libraries which are
neither provided by Grace nor the operating system. You will
need to install these libraries yourself. This applies to
M*tif, PDF (see question
Output Devices)
and probably other libraries.
If the message is exactly Can't find library libXm.so
(usually this happens on GNU/Linux systems ...) then you don't have
M*tif (the Xm libraries) installed (see question
M*tif), or the linker doesn't
know where it is.
In the first case, try downloading LessTif. In the second case,
you have to tell your linker where it is (may be
a platform-specific task). On GNU/Linux look at the file
/etc/ld.so.conf. It contains pathnames of the directories
where dynamic libraries are stored. Add (as root) your directory
to this file and run ldconfig -v. Now the libraries
should be in the list. If you're not root you may try
to adjust the environment variable LD_LIBRARY_PATH
to include the required pathname.
For some versions of Motif, the ``soname'' (which identifies the version of the library and is stored somewhere in the library) on your computer doesn't match the soname of the library on the computer where your copy of Grace was compiled on. Then you should use a (semi)statically linked version or compile Grace on your computer.
This means that Grace made an incorrect access to an X library. This is most probably not Grace's fault. Probably a not-yet-correctly-implemented LessTif function (see question M*tif) caused this behaviour. If you use LessTif, try to get the latest version (see question M*tif). If this error persists, report it as a bug (question Bug Reports).
Detect whether you are using a version linked against LessTif. "xmgrace -version" and "ldd xmgrace" are useful commands for this purpose.
If you are using LessTif, read the according FAQ M*tif else report it as a bug ( Bug Reports).
Get the XKeySymDB file from the X11R6 distribution. Put it
somewhere where you can access it and set the XKEYSYMDB
environment variable to
"/place/where/you/put/XKeysymDB". See question
Environment Variables on how
to set environment variables.
This is a known bug of Motif implementation on Solaris 2.5.1 (both Sparc and Intel hardware). Ask your vendor for a patch.
You have probably tried to run Grace without installing it, just after compilation. You got the following message :
scanFontDBase(): Font Database File not found
T1_InitLib(): Fatal error scanning Font Database File
--> Broken or incomplete installation - read the FAQ!
Grace uses either the GRACE_HOME environment variable
or a compiled in default path to find the font database. If
the variable is not set and you have not installed the
database with make install it cannot find it. If you
want to test Grace before installing it, you should set the
environment variable to the distribution directory (the one
where the file configure lies), this is what the
dotest script does when you run make check. The
easiest thing to do however is to install everything with
make install. See question
Environment Variables on how to set environment
variables.
If you get this message after installing a prebuilt package,
then you have either forgotten to download the platform-independent
part of the installation (named like grace-x.y.zz.common.tar.gz) or
not set the GRACE_HOME environment variable, see a few lines
above.
This is a known bug in Motif-2.1. Most vendors have fixed it in their ports and/or have a patch ready, but not all, a notable exception being Motif libraries shipped by Red Hat for GNU/Linux for Intel hardware (versions 6.*). Grace has a workaround for this bug. In order to enable it, add the following lines to the X resources:
XMgrace*XmDrawingArea.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmRowColumn.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmForm.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmFrame.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmScrolledWindow.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmFileSelectionBox.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmScale.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmCommand.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
XMgrace*XmMessageBox.translations: #override\n\
Ctrl <Btn1Down>: do_nothing()
It should be exactly the size of the hardcopy (A4/US letter). If not, check your X server settings (run `xdpyinfo' and watch the "dimensions:" line; check the numbers with a ruler).
Are you using OpenMotif 2.2 (see Help/About)? It's known to behave wrongly with several locale settings. Try setting the shell variable LANG to a safe value, e.g. "C". The bug is known and fixed ( bug #1257). Nag your vendor to apply the patch.
It happens with OpenMotif 2.2 and some locale settings. See the previous entry for a remedy.
This happens when a Unicode font is picked by the X/Motif and, for a reason, is treated as a wchar one (so you see one "square" glyph for every two chars). Try different font settings; for starters, run
xmgrace -xrm "XMgrace*fontList:fixed"
FC4 uses a BETA version of OpenMotif 2.3 (see Help/About). The bug is known and fixed ( bug #1331). Ask Fedora folks to apply the patch.
A project is a file which contains all information necessary to restore a plot created by Grace.
A parameter file contains informations about settings. Every
batch command of Grace is a valid line in a parameter
file. A parameter file is essentially a project file without
sets in a slightly different format (i.e. without leading
@s).
You can read in several kinds of files where data is arranged in columns separated by spaces or tabs. Lines beginnig with "#" are ignored.
The option Read Block Data can be used to read in files
where the values are organized in columns. You
can interactively select the type of set to be created and
which columns should be used. Refer to the User's Guide
(question
User's Guide) for details.
Strictly speaking, it's not a data format. Rather, you may want to use the relevant command line switch to read in a block data file and automatically assign the data columns to sets of the XY type so that the first column of the block data is used as X for all the sets and the rest of the data columns are assigned to Y's. Refer to the User's Guide (question User's Guide) for details.
The Julian Date, not to be confused with the Julian calendar, is a format to represent the time in a single number. Julian Date 0 is a day way in the past, namely the 1st January 4713 before Christ (don't ask me why). The following days are numbered sequentially, each day starting at noon. This numbering scheme is in wide use, especially in astronomy, and is used for the internal representation of dates in Grace. Some further explanations are given on this page.
The convcal utility in $GRACE_HOME/auxiliary/ can
be used for about any to Julian date convertion.
There are three ways to invoke Grace. The full-featured
GUI-based version is called xmgrace. A batch-printing
version is called gracebat (see question
Gracebat). A command-line interface mode
is called grace.
All three of them are usually located in $GRACE_HOME/bin/.
gracebat is simply a copy of Grace named gracebat
or a symbolic link from gracebat to Grace. In the case
of the symbolic link:
ln -s xmgrace gracebat
done wherever the Grace binary is located will do the trick
(rehash or logout and login to make sure that gracebat
shows up in your path). Executing gracebat with no
command line parameters or data files will produce a
hardcopy on the default printer.
There are several ways: the init files, X Resources, and environment (shell) variables. Please refer to the User's Guide (question User Guide) for details.
There are few, the most important being GRACE_HOME.
It specifies the directory where the Grace files (fonts,
docs, libs, ...) are stored. Default is /usr/local/grace.
You can set environment variables using (e.g.):
export GRACE_HOME="/usr/local/grace"
in bash and sh or
setenv GRACE_HOME "/usr/local/grace"
in tcsh and csh.
Please refer to the User's Guide (question User Guide) for description of all relevant variables.
Quite a few. You can display them with xmgrace -help.
Or check for the man page xmgrace(1). However it may not always be up-to-date.
As with any X application, use the "-bg <colorname> -fg <another_colorname>" command line flags. Or, define the relevant X resources:
XMgrace*foreground: ...
XMgrace*background: ...
The standard set is the regular (x,y) set, but there are others including error bars or descriptive strings. See the User's Guide (question User's Guide) for details.
Use two overlaying graphs, one with a scale on the left(bottom), the other one on the right (top). Thus you can achieve the desired effect, but you'll need to pay close attention to which graph is the 'current' graph. This is also how to display a second scale on the top (right) side of the graph.
The support for polar plots is currently being
implemented, so you can expect polar plots to work
soon. The polar coordinates can be selected from the
"Plot/Graph Appearance" menu. Please refer to
the User's Guide (question
User Guide)
for details.
Yes, Grace has all these features. Wherever you can type a
text in Grace, e.g. Axis labels, graph title, text from
Plot->Drawing objects, etc., you can use all those
features within the same text. Please refer to the User
Guide (question
User's Guide) for
details.
If you asked this question, then you are probably familiar with
the issue of keymap modifying in X. Once you configured the key
mapping (with the use of xmodmap), you can enter the
extended characters from the keyboard in any text input field. If,
in addition, the appropriate for your language font encoding is
anything but ISO Latin1 (used in most Western Europe countries),
you'll have to tell Grace so. See the
next question.
Yes. Starting with version 5.0.1, you can use your own fonts, in addition to the standard 14 fonts which include Times-Roman, Helvetica, Courier, Symbols and Zapf Dingbats and come with Grace, and as a replacement for the default fonts (for the purporse of localization). As well, an alternative encoding scheme can be specified.
Please refer to the User's Guide (question User's Guide) for details.
By default, numbers are saved with eight valid digits. To set your own precision, use the command
DEFAULT SFORMAT formatstring
in an init resource file (see question
Customization) with formatstring being in the
printf(3) format.
As well, you can set the precision on a per-project basis. When you save a project for the first time (or use "File/Save as"), there is a relevant "Data format" field in the popup you are presented with.
For time plots, the default precision may be insufficient. See the previous question on how to alter it.
From Xmgr-4.1.2 on, each project file starts with a string
giving the version number by which is was saved. These
files should cause no problems. You can modify older files
by inserting a version line at the beginning. For example,
@VERSION 40102 stands for version 4.1.2. If you have no
idea what version of Xmgr your file was created with, try some.
In most cases, 40102 would do the trick. Also, make sure to read
the "Xmgr to Grace migration" section of the User's Guide
(question
User's Guide).
In Xmgr-4.1.0, support for the binary file format (the
former default one) was dropped. You must use the
grconvert utility supplied with the Grace
distribution in order to convert the files. This can
easily be achieved defining an input filter like in the
gracerc sample file which comes with Grace.
Make sure you added a valid @VERSION versionid line to the
beginning of the file.
Yes. You can use your favorite compression program (e.g. `gzip') as input or output filter so that files on disk are automagically (de)compressed. Just add the lines
DEFINE IFILTER "gzip -dc %s" PATTERN "*.gz"
and
DEFINE OFILTER "gzip - > %s" PATTERN "*.gz"
into your personal grace init file. Then, everytime you
specify a file name that ends with .gz, gzip is used
as input and output filters. You can use this mechanism to
do other things, e.g. reading and storing files into a
database.
Well, not yet. The import of images will be implemented in a future release.
PostScript (for printing), EPS (encapsulated PostScript; for the inclusion of graphics into e.g. LaTeX documents), PNM (PBM/PGM/PPM), MIF (for inclusion in FrameMaker) and SVG (Scalable Vector Graphics) are implemented by default.
Additionally, if some extra libraries are installed, listed in the User's Guide (question User's Guide), the JPEG, PNG, and PDF backends will be built as well.
You can get various other formats using netpbm and pstoedit.
Bitmaps: Using the PNM device + the netpbm utils
(available at e.g.
ftp://ftp.x.org/contrib/utilities/ one can get
TIFF, GIF, G3, BMP, PCX,... (conversion can be done on
the fly with appropriate filter definitions).
Notice that the direct support of the GIF format is impossible due to the copyright policy of Unisys - it's not a technical problem. In fact it was supported in earlier versions but to avoid any legal problems this feature has been removed.
One can use pstoedit to convert PS to a lot of other vector formats: MIF, CGM, xfig's, tgif's, Windoze and OS/2 metafiles,... even Java applets!
Region operations have no meaning by themselves. Regions are restriction conditions applied to data set(s) which a transformation is performed on. For example, to kill data points in a region, use "Evaluate expression", select same source and dest set(s), leave the "formula" field empty, select your region in the "Restriction" menu, check "Negated".
You can use several date/time formats in input data files. Make sure, however, that the time fields don't contain space separators inside, e.g. 1999-12-31-23:59:59.5
Also, you can use an external program to convert the data into the Julian Date format, like the one (convcal) that is supplied with Grace.
This can be done using the "Plot/Plot appearance" popup.
This changes the background of the entire canvas, not only the background of graphs.
You may edit your Default.agr file in
$GRACE_HOME/templates. Just add lines similar to
@map color 2 to (255, 0, 0), "red"defining a RGB value and an according name for that color triplet. Please notice that altering colors 0 (white) and 1 (black) is strongly discouraged.
A named pipe is a pseudo file to which one application writes data which another one reads from it.
Applications like measurement programs can write data to a pipe and make it thus available to Grace which reads from the pipe. So Grace can serve as data displayer for otherwise non-graphical programs.
Refer to the User's Guide (question User's Guide) or the tutorials (question Tutorials) for further information.
One example for using pipes is included in the `make
tests' slide show.
Start Grace with -pexec "G0 OFF" or load a parameter file with the above command.
LaTeX does not do hard clipping of EPS files unless instructed to do
so. Use \includegraphics*{filename} and NOT
\includegraphics{filename} (package graphics) or
\includegraphics[clip]{filename} (package graphicx). If
using the epsf package, remember to include the \epsfclipon
flag (but note that the epsf package is obsolet and buggy
and not maintained by the LaTeX team and in general should not be
used).
The erasing comes about because Grace fills the background with the page size and not the bbox size. The background filling can be disabled from the "Plot/Plot appearance" popup.
By default, the PS driver uses Level 2 features, while your printer may not be PostScript Level 2 compliant. You can force the use of PS Level 1 only features in the PostScript device setup, though output may be not exactly as expected (there will be no pattern fills, for example).
Select the correct paper size in the Device setup
popup.
You can also try the command psresize from the psutils package in order to resize a Postscript file generated by Grace.
You're using a localized version of OS. You have either LANG or LC_NUMERIC shell variables set, so Grace uses the locale setting to produce numeric labels. Set at least LC_NUMERIC to C or POSIX to disable this behaviour. Notice that there is nothing specific to Grace about locale. Either you want the localization or not. Setting by default LANG to anything but C/POSIX assumes you do.
In "Plot/Axis props", enable logarithmic axis scaling, then go to the "Tick labels" tab of this dialog, find the "Axis transform" input field in the "Extra" frame, and enter there "10*log10(10*$t)" (w/o quotes, of course).
If you find some columns are too narrow to show all significant digits, you can drag the vertical rules using Shift+Button 2.
The -param flag and its argument should be placed on the command line after the data filenames. Alternatively, disable the autoscale with -autoscale none - but before your data is read in.
Use "Create new->By formula" from any set selector popup menu.
Template is just an empty (in the sense that there are no data sets) but otherwise a valid project file. So just put your favorite template's filename as the first argument on the command line. If your script creates several plots, use 'new from "filename"' to initialize a new project from the non-default template.
A part of them are saved with the project; most of the rest are available via command-line options and/or X resources. A more homogeneous approach will be implemented in a future version.
Enlarge "Max drawing path length" in Edit/Preferences. Also, consider whether you really need that huge number of points drawn connected by line?
It is the Levenberg-Marquardt algorithm, based on LMDIF from MINPACK, with some modifications.
Lots. Almost every mouseclick in the GUI has an equivalent in the batch language. See the User's Guide (question User's Guide) for details.
Currently not at all. This will be implemented in a later release.
Example - make a batch file with the following commands:
fit formula "y = a0 + a1 * sin (a2 + x * pi / 180)"
fit with 3 parameters
fit prec 0.05
a0 = 1
a0 constraints on
a0min = 0
a0max = 2
a1 = 1
a1 constraints off
a2 = 1
a2 constraints off
nonlfit (s0, 100)
This assumes that your original curve is in set s0 and that you want to make 100 iterations.
nonlfit() doesn't produce any plots by itself. It only
fits. I.e., at this point, you can use the fitted
values A0, A1, A2...:
Plot a set, e.g.:
s3 on
s3 length s0.length
s3.x = s0.x
s3.y = a0 + a1 * sin (a2 + x * pi / 180)
Use for another fit as the initial values, or just ECHO them
(to stdout) with ECHO A0.
No, but you can do something like this (given the set type was properly defined):
S0 POINT expr, expr
S0.Y1[S0.LENGTH - 1] = expr
S0.Y2[S0.LENGTH - 1] = expr
...
Not yet. Although it would be nice to have such a
function, it is quite hard to implement. We can only ask you
to be careful with certain actions and remember to save
often and early (TM).
No. Not yet, I should say. Be patient. It may take quite a while to implement it, though.
Among the many features planned to be introduced in the future are enhancing the spreadsheet-like frontend for dataset operations, contour plots, many-level undo/redo, image import and manipulations, a library for 2-way communication, ... Then 3D plots would come :-)
Probably. If you have an idea for improvement, post it as a wish to the w3todo web page (see question Known Bugs).
You are not required to, but you if wish, refer to the home page link (see Grace home page).