wxMaxima is a graphical user interface that allows to use all of maxima's functions providing convenient wizards for accessing the most commonly used of them. This manual attempts to describe the unique features that make this program one of the most popular GUIs for maxima.
In the open-source domain big systems are normally split into smaller projects that are easier to handle for small groups of developers. For example a CD burner program will consist of a command-line tool that actually burns the CD and a graphical user interface that allows the user to use it without having to learn about all the command-line switches and in fact without using the commandline at all. One advantage of this approach is that the developing work that was invested into the command-line program can be shared by many programs without having to re-invent the wheel: The same cd-burner command-line program can be used as a “send-to-cd”-plug-in for a file manager application, for the “burn to CD” function of a music player and as the CD writer for a DVD backup tool. Another advantage is that splitting one big task into smaller parts allows to provide several user interfaces for the same program: A computer algebra system could be be the logic behind a arbitrary precision calculator application, it can do automatic transforms of formulas in the background of a bigger system (e.G. Sage) or actually used as a full-fledged computer algebra system (which is the case with wxMaxima).
Maxima is a full-featured computer algebra system (CAS). In other words it is a program specialized in solving mathematical problems by rearranging formulas and finding a formula solving the problem as opposed to just outputting the numeric value of the result.
There is extensive documentation for maxima available in the internet part of which can be found in wxMaxima's help menu. To make access to the documentation easier if the <Help> key is pressed (on most systems that would be the <F1> key) wxmaxima's context-sensitive help feature will automatically jump to maxima's manual page for the command at the cursor.
wxMaxima is a graphical user interface that provides the full functionality and flexibility of maxima providing the user with a graphical display and many features that make working with maxima easier. For example wxMaxima allows to export any cell's contents (or, if that is needed, any part of a formula, as well) as text, as LaTeX or as MathML specification at a simple right-click.
The calculations itself are done by the maxima command-line tool in the background.
Most of wxMaxima should be self-explaining. Therefore this manual will concentrate on describing facts that won't need more time to read about than to be actually explored.
One of the very few things that aren't standar ist that wxMaxima organizes the data for maxima in cells that are only evaluated (which means: sent to maxima) when the user requests this. This approach might feel unfamiliar at the first sight. But it drastically eases work with big documents (where the user certainly doesn't want every small change to automatically to trigger a full re-evaluation of the whole document) and is very handy for debugging.
The cells wxMaxima automatically creates on typing some text are maxima input cells that will eventually be sent to maxima.
On evaluation of an input cell's contents the input cell maxima
assigns a label to the input (by default shown in red and recognizable
by the %i) by which it can be referenced lateron. The output
maxima generates will be shown in a different style and preceded by maxima
by a label beginning with %o.
Besides the input cells wxMaxima allows for text cells for documentation, image cells, title cells, chapter cells and section cells; Every cell has it's own undo buffer so debugging by changing the values of several cells and then gradually reverting the unneeded changes is rather easy. Besides this the worksheet itself has a global undo buffer that can undo cell edits, adds and deletes.
The worksheet is organized in cells that work like very much like the styles word processors offer. Each cell can contain one of the following types of content:
While it sometimes is both desirable to allow selecting multiple cells or only part of a cell for export or Drag-and-Drop beginning such an action in the middle of one cell and ending it in the middle of another will most certainly lead to unexpected results.
wxMaxima works around this by defining two types of cursors wxMaxima will switch between automatically when needed:
wxMaxima contains an autocompletion feature that is triggered via the menu (Cell/Complete Word) or alternatively by pressing the key combination <Ctrl>+<k>. The autocompletion is context-sensitive and if activated within an unit specification for ezUnits it will offer a list of applicable units.
Besides completing the current command's or variable's name the autocompletion is able to show a template for most of the commands indicating the type (and meaning) of the parameters this program expects. To activate this feature press <Shift>+<Ctrl>+<k> or select the respective menu item (Cell/Show Template).
Computers traditionally store characters in 8-bit values: This allows for a maximum of 256 different characters and all letters, numbers, and control symbols (end of transmission, end of string, lines and edges for drawing rectangles for menus etc.) of nearly any given language fit there.
For most countries the codepage of 256 characters that has been chosen doesn't include greek letters, though. To overcome this limitation unicode has been invented: A method of including characters that aren't normally used in the english language in a text that (as long as only the basic form of latin characters is used) looks like plain 8-bit ASCII.
Maxima allows for unicode characters if it runs on a lisp that supports them and if the wxWidgets library wxMaxima is built on supports unicode characters, too, wxMaxima can be built with unicode support. In this case it provides a method of entering greek characters:
The lowercase greek letters actually can be entered both by enter a lating letter or the whole latin name of the greek letter followed and preceded by a press of the escape key:
a alpha i iota r rho
b beta k kappa s sigma
g gamma l lambda t tau
d delta m mu u upsilon
e epsilon n nu f phi
z zeta x xi c chi
h eta om omicron y psi
q theta p pi o omega
The same is tue for the uppercase greek letters:
A Alpha I Iota R Rho
B Beta K Kappa S Sigma
G Gamma L Lambda T Tau
D Delta M Mu U Upsilon
E Epsilon N Nu P Phi
Z Zeta X Xi C Chi
H Eta Om Omicron Y Psi
T Theta P Pi O Omega
This mechanism also allows to enter some miscellaneous mathematical symbols:
2 squared
3 to the power of three
/2 1/2
sq root
ii imaginary
ee element
hb h barred
in in
impl,implies implies
inf infinity
empty empty
TB Big triangle right
tb small triangle right
and and
or or
xor xor
nand nand
nor nor
equiv equivalent
not not
union union
inter intersection
subseteq subset or equal
subset subset
notsubseteq not subset or equal
notsubset not subset
It is to note that a maxima running on a lisp without unicode support might not be able to deal with files that contain special unicode characters.
Shortcuts to the most important maxima commands and a history of the last issued commands can be accessed using the side panes. They can be enabled using the “Panes” entry in the “Maxima” menu.
Markdown in many cases collides with the notations that are frequently used for mathematics. wxMaxima will recognize bullet lists, though, for the HTML and TeX export when the items are marked with stars.
Ordinary text
* One item, indentation level 1
* Another item at indentation level 1
* An item at a second indentation level
* A second item at the second indentation level
* A third item at the first indentation level
Ordinary text
wxMaxima will also recognize => and replace it by a
cogito => sum.
Other symbols the markdown parser will recognize are <= and
>= for comparisons, a double-pointed double arrow (<=>),
single- headed arrows (<->, -> and <-) and
+/- as the respective sign.
Most hotkeys can be found in the text of the respective menus. Since they are actually taken from the menu text and thus can be customized by the translations of wxMaxima to match the needs of users of the local keyboard there is no usee of documenting them here. There are a few hotkeys or hotkey aliases, though, that aren't documented there:
Ctrl+Shift+Delete deletes a complete cell.
Ctrl+Tab or Ctrl+Shift triggers the auto-completion mechanism.
Ctrl++ or Ctrl+- Zoom in or out.
.mac files are ordinary text files that can be read using maxima's read command:
%i1 read("test.mac");
They can be used for writing own libraries but since they don't contain enough structural information they cannot be read back directly into wxMaxima.
.wxm files contain the input for maxima, as well as any text cells, title cells and chapter or section cells the user typed in. Pictures and maxima's output aren't saved along with the .wxm file, though.
This xml-based file format saves all text and images the work sheet contains. It is the preferred file format now and comes in two flavors:
The animation framerate that is used for new animations if the value of wxanimate_framerate isn't changed from the maxima side.
After the next start plots embedded into the worksheet will be created with this size if the value of wxplot_size isn't changed by maxima.
This option enables two things:
If this value is set to a value bigger than zero maxima will work in a more mobile-device-like fashion:
wxMaxima aims to be but a graphical user interface for maxima. In some cases it adds functionality to Maxima, though. These cases are described here.
Plotting (having fundamentally to do with graphics) is a place where a graphical user interface will have to provide some extensions to the original program.
Maxima normally instructs the external program gnuplot to open a separate window for every diagram it creates. Since many times it is convenient to embed graphs into the work sheet instead wxMaxima provides its own set of plot functions that don't differ from the corresponding maxima functions save in their name: They are all prepended by a “wx”. For example wxplot corresponds to plot, wxdraw corresponds to draw and wxhistogram corresponds to histogram.
The configure dialog provides a way to change the default size plots are created with which sets the starting value of wxplot_size. The plotting routines of wxMaxima respect this variable that specifies the size of a plot in pixels. It can always be queried or used to set the size of the following plots:
%i1 wxplot_size:[1200,800];
%o1 [1200,800];
%i2 wxdraw2d(
explicit(
sin(x),
x,1,10
)
)$
If the size of only one plot is to be changed maxima provides a canonical way to change an attribute only for the current cell.
%i1 wxplot_size:[1200,800];
%o1 [1200,800];
%i1 wxdraw2d(
explicit(
sin(x),
x,1,10
)
),wxplot_size=[1600,800]$
Gnuplot doesn't seem to provide a portable way of determining is it supports the high-quality bitmap output the cairo library provides. On systems where gnuplot is compiled to use this library the pngcairo option from the configuration menu (that can be overridden by the variable wxplot_pngcairo) enables support for antialiasing and additional line styles.
The with_slider_draw command is a version of wxdraw2d
that does prepare multiple plots and allows to switch between them
by moving the slider on top of the screen. If ImageMagick is installed
wxMaxima even allows to export this animation as an animated gif.
The first two arguments for with_slider_draw are the name of
the variable that is stepped between the plots and a list of the
values of these variable. The arguments that follow are the ordinary
arguments for wxdraw2d:
with_slider_draw(
f,[1,2,3,4,5,6,7,10],
title=concat("f=",f,"Hz"),
explicit(
sin(2*%pi*f*x),
x,0,1
),grid=true
);
The same functionality for 3d plots is accessible as with_slider_draw3d.
There is a second set of functions making use of the slider
wxanimate_draw and
wxanimate_draw3d:
wxanimate_draw(
a, 3,
explicit(sin(a*x), x, -4, 4),
title=printf(false, "a=~a", a));
Normally the animations are played back or exported with the frame rate chosen in the configuration of wxMaxima. To set the speed an individual animation is played back the variable wxanimate_framerate can be used:
wxanimate(a, 10,
sin(a*x), [x,-5,5]), wxanimate_framerate=6$
The animation functions have a pitfall that one has to be aware of when using them: The slider variable's value are substituted into the expression that is to be plotted - which will fail, if the variable isn't directly visible in the expression. Therefore the following example will fail:
f:sin(a*x);
with_slider_draw(
a,makelist(i/2,i,1,10),
title=concat("a=",float(a)),
grid=true,
explicit(f,x,0,10)
)$
If maxima is forced to first evaluate the expression and then asked to substitute the slider's value plotting works fine instead:
f:sin(a*x);
with_slider_draw(
a,makelist(i/2,i,1,10),
title=concat("a=",float(a)),
grid=true,
explicit(''f,x,0,10)
)$
While not being a provided by wxmaxima this feature of maxima (on setups that support it) sometimes comes in handily. The following example comes from a post from Mario Rodriguez to the maxima mailing list:
load(draw);
/* Parabola in window #1 */
draw2d(terminal=[wxt,1],explicit(x^2,x,-1,1));
/* Parabola in window #2 */
draw2d(terminal=[wxt,2],explicit(x^2,x,-1,1));
/* Paraboloid in window #3 */
draw3d(terminal=[wxt,3],explicit(x^2+y^2,x,-1,1,y,-1,1));
if the .wxmx file format is being used embedding files in a wxMaxima project can be done as easily as per drag-and-drop. But sometimes (for example if an image's contents might change lateron) it is better to tell the file to load the image on evaluation:
show_image("Mann.png");
If the maxima user directory there is a text file named wxmaxima-init.mac the contents of the file is passed to maxima automatically every time a new worksheet has been started.
To find out which directory maxima uses as the user directory just type in the following line:
maxima_userdir;
The answer from Maxima will specify the name of the directory that the startup file can be placed in.
%o1 /home/username/.maxima
read_matrix) to work without specifying the whole path to the
file that has to be read or written. On windows this is
deactivated, though: The Lisp Standard doesn't contain a concept of
the current working directory. Therefore there is no standard
way of setting it and changing to a directory that isn't on
the drive maxima has been installed to might cause maxima to
try to read is own package files from this drive, too, instead
of from the drive maxima has been installed to. Setting
wxchangedir to true tells wxMmaxima that it has to
risk that and to set maxima's working directory.
The function (table_form) displays a 2D list in a form that is
more readable than the output maxima's default output routine.
table_form(
[
[1,2],
[3,4]
]
)$
wxMaxima provides a few functions that gather bug reporting information about the current system:
wxbuild_info() gathers information about the currently
running version of wxMaxima
wxbug_report() tells how and where to file bugs
Since maxima (the program that does the actual mathematics) and wxMaxima (providing the easy-to-use user interface) are separate programs that communicate by the means of a local network connection the most probably case is that this connection is somehow not working. For example a firewall could be set up in a way that it doesn't only prevent against unauthorized connections from the internet (and perhaps to intercept some connections to the internet, too) but also to block inter-process-communication inside the same computer. Note that since maxima is being run by a lisp processor the process communication is blocked from does not necessarily have to be named “maxima”. Common names of the program that opens the network connection would be sbcl, gcl, ccl or similar instead.
On Un*x computers another possible reason would be that the loopback network that provides network connections between two programs in the same computer isn't properly configured.
Internally most modern xml-based formats are ordinary zip-files with one speciality: the first file in the archive is stored uncompressed and provides information about what type of program can open this file.
If the zip signature at the end of the file is still intact after renaming a broken .wxmx file to .zip most operating systems will provide a way to extract any portion of information that is stored inside it. The can be done when there is the need of recovering the original image files from a text processor document. If the zip signature isn't intact that does not need to be the end of the world: If wxMaxima during saving detected that something went wrong there will be a wxmx~ file whose contents might help and even if there isn't such a file: If the configuration option is set that .wxmx files have to be optimized for version control it is possible to rename the .wxmx file to a .txt file and to use a text editor to recover the file's contents.
This might be caused by the fact that a closing brace, bracket, parenthesis or hyphenation mark is missing: In this case maxima waits until it gets the rest of its input. If that isn't the case the operating system normally provides a way to see if maxima is actually really working forever trying to solve the current problem.
The jsMath fonts allow for excellent 2D-display of equations. But there are of broken versions of this package that crash wxMaxima. A working version can be downloaded from http://www.math.union.edu/~dpvc/jsmath/download/jsMath-fonts.html math.union.edu. If this doesn't help jsMath can be deactivated in the Styles tab of wxMaxima's configuration dialogue.
wxMaxima relies on a third-party tool (ImageMagick) to convert animations to the animated gif format. This will obviously only work if this package is installed and known to the system (on windows the path to ImageMagick's convert.exe has to be part of the PATH system variable to make the system find it).
Another possible reason of not getting an animated gif is that this image would exceed the format's (or ImageMagick's) capabilities:
This means that wxMaxima was unable to read the file maxima was supposed to instruct gnuplot to create.
Possible reasons that might cause this are:
implicit_plot but this package wasn't loaded by maxima's
load() command before trying to plot.
The value of the slider variable by default is only substituted into the
expression that is to be plotted if it is visible there. Putting an
ev() around this expression should resolve this problem.
There are separate undo functions for cell operations and for changes inside of cells so chances are low that this ever happens. If it does there are several methods to recover data:
%i1 playback();
One possible reason is that maxima cannot be found in the location that is set in the “maxima” tab of wxMaxima's configuration dialog and therefore won't run at all. Setting the path to a working maxima binary should fix this problem.
It is theoretically possible that wxMaxima doesn't realize that maxima has finished calculating and therefore never gets informed it can send new data to maxima. If this is the case “Trigger evaluation” might resynchronize the two programs.
On windows File I/O isn't relative to the directory of the current
file by default. If you store the maxima file on the drive wxMaxima is
installed to setting wxchangedir to true will fix
that for load, read_list, batch,
read_matrix, save and all similar commands.
Setting this variable to true might have a drawback, though:
Maxima knows which directory it is installed in and will search for
any additional package that is requested by a load command in
this directory, too. But it might not know which drive it is installed
on. If wxchangedir is true and the current file is saved
on a different drive than the one maxima is installed on maxima
therefore might fail to load the additional packages it was bundled
with.
Installing the package ibus-gtk should resolve this issue. See
(https://bugs.launchpad.net/ubuntu/+source/wxwidgets3.0/+bug/1421558) for details.
If your maxima is based on sbcl the following lines have to be added to your .sblrc:
(setf sb-impl::default-external-format :utf-8)
The location this file has to be put in order to be found by sbcl is system- and installation-specific. But any sbcl-based maxima that already has evaluated a cell in the current session will happily tell where it can be found after getting the following command:
:lisp (sb-impl::userinit-pathname)
There is: Just add the following lines to the LaTeX preamble (for example by using the respective field in the config dialog):
\usepackage[a4paper,landscape,left=1cm,right=1cm,top=1cm,bottom=1cm]{geometry}
Most operating systems provide less complicated ways of starting programs than the command line so this possibility is only rarely used. wxMaxima still provides some command line switches, though.