XPPAUT(1)

💖 XPPAUT 💖

okay bestie, welcome to the manual page for xppaut, from the XPPAUT Documentation section (section 1, obviously, she's a command 👑). Full name on her birth certificate: X Phase plane plus AUTO, and she solves many kinds of equations. no big deal. 💅

---

✨ SYNOPSIS ✨

xppaut [-silent] [-xorfix] [-convert]
       [-newseed] [-ee] [-allwin]
       [-white] [-setfile file] [-runnow]
       [-bigfont font] [-smallfont font] [-parfile file]
       [-outfile file] [-icfile file] [-grads boolean] [-bell boolean]
       [-forecolor color] [-backcolor color] [-backimage image]
       [-quiet boolean] [-logfile file] [-internset boolean] [-uset
       setname]
       [-rset setname] [-include file]  [-qics] [-qpars] [-qsets]
       [-anifile file] [file...] [-mkplot] [-plotfmt format]
       [-ncdraw boolean] [-dfdraw N] [-version] [-noout]

like. look at her. so many flags. a whole wardrobe 🎀

---

🌸 DESCRIPTION 🌸

so xppaut is the tool you call when you need to solve:

• differential equations
• difference equations
• delay equations
• functional equations
• differential-algebraic equation
• boundary value problems
• stochastic equations

the way she does ALL of that 😭 she brings together a bunch of genuinely useful algorithms and she's written in C. every bit of the graphics and the interface is built using the X Window System protocol client library Xlib <http://www.xfree86.org>. periodt.

here's the capability list, and bestie, it's giving main character energy:

• Handles up to 1950 differential equations.
• There are over a dozen solvers including several for stiff systems, a solver for integral equations and a symplectic solver
• Up to 10 graphics windows can be visible at once and a variety of color combinations is supported
• PostScript output is supported as well as GIF and animated GIF movies
• Post processing is easy and includes the ability to make histograms, FFTs and applying functions to columns of data
• Equilibria and linear stability as well as one-dimensional invariant sets can be computed
• Nullclines and flow fields aid in the qualitative understanding of two-dimensional models
• Poincare maps and equations on cylinders and tori are also supported
• Some useful averaging theory tricks and various methods for dealing with coupled oscillators
• Equations with Dirac delta functions are allowable
• Animations of simulations such as a little pendulum moving back and forth or lamprey swimming
• A curve-fitter based on the Marquardt-Levenberg algorithm which lets you fit dynamical systems to data
• Generate "movies" of three-dimensional views of attractors or parametric changes in the attractor as some parameters vary
• Dynamically link to external subroutines
• From the command line type /dev/stdin as the file and you can write the ODE on the fly

the /dev/stdin thing? writing your ODE on the fly?? that is SO iconic, iykyk 🦋

---

🎀 OPTIONS 🎀

• -silent — batch run, no interface, and she just dumps the solutions into a file. quiet queen. 🤫
• -xorfix — a work-around for exclusive Or with X on some monitors/graphics setups
• -convert — converts old style ODE files (like phaseplane) into the new ODE style
• -newseed — randomizes the random number generator, which will often use the same seed otherwise (ngl she's a creature of habit)
• -ee — emulates shortcuts of Evil Empire style (MS) 😭
• -allwin — brings XPP up with all the windows visible. she's an open book 💖
• -white — swaps foreground and background colors
• -setfile filename — loads the set file before starting up
• -runnow — runs the ode file immediately upon startup (this one is implied by -silent)
• -bigfont font — use the big font whose filename is given
• -smallfont font — use the small font whose filename is given
• -parfile filename — loads parameters from the named file
• -outfile filename — sends output to this file (default is output.dat)
• -icfile filename — loads initial conditions from the named file
• -forecolor color — hexadecimal color (e.g. 000000) for the foreground
• -backcolor color — hexadecimal color (e.g. EDE9E3) for the background
• -mwcolor color — hexadecimal color (e.g. 808080) for the main window
• -dwcolor color — hexadecimal color (e.g. FFFFFF) for the drawing window
• -backimage filename — name of a bitmap file (.xbm) to tile in the background

for example, the following text saved to a file named stipple2.xbm can be loaded to impart a stippled background.

#define stipple2_width 2
#define stipple2_height 2
static char stipple2_bits[] = {
 0x02,0x01};

• -grads B — color gradients will (B=1) or will not (B=0) be used
• -width N — minimum width in pixels of the main window
• -height N — minimum height in pixels of the main window
• -bell B — the system bell on events will (B=1) or will not (B=0) be used
• -internset B — internal sets will (B=1) or will not (B=0) be run during a batch run
• -uset setname — the named internal set will be run during a batch run
• -rset setname — the named internal set will not be run during a batch run
• -include filename — the named file will be included (see the include directive)
• -qsets — query internal sets (output saved to OUTFILE)
• -qpars — query parameters (output saved to OUTFILE)
• -qics — query initial conditions (output saved to OUTFILE)
• -quiet B — verbose log messages will (B=0) or will not (B=1) be written
• -logfile filename — verbose log messages get written to the named file instead of stdout
• -anifile filename — load an animation (.ani) from the named file
• -mkplot — produce graphics from the solution (this one requires -silent)
• -plotfmt format — the graphics format (see -mkplot). supported values for format include svg and ps.
• -ncdraw B — nullclines will (B=1) or will not (B=0) be produced (see -mkplot) for graphics output
• -dfdraw N — the vector field may be produced (see -mkplot) for graphics output. supported values for N are none (N=0), direction field (N=1), scaled direction field (N=2), and colorized (N=3). the number of grid values used in producing the field is determined by the nmesh @-option (see .xpprc or .ode syntax).
• -version — outputs the version of this software and exits. she said bye ✌️
• -noout — during a batch run (see -silent), no solution output (.dat) file will be produced

---

🦋 ENVIRONMENT 🦋

• XPPSTART — the file browser will open to the specified path. this may be useful in an instructional setting, to point to a mapped drive containing course materials.
• XPPHELP — path to the XPPAUT documentation file <xpphelp.html> (e.g. /usr/share/doc/xppaut/html/xpphelp.html)
• XPPBROWSER — web browser to view the documentation (e.g. /usr/bin/firefox)

---

💜 FILES 💜

every user can customize the behavior and appearance of Xppaut through the file “$HOME/.xpprc”. and where does $HOME point? to the user's home directory, duh 💅. on most systems $HOME will already be set, so don't stress.

each option line in .xpprc begins with the “@” symbol, followed by a comma-separated list of options. comment lines begin with the “#” symbol and are just ignored. like, blocked. 🙈

# Example .xpprc file
@ maxstor=50000
@ meth=qualrk,tol=1e-6,atol=1e-6
#Set up a customized look
@ but=quit:fq,bell=1
@ bigfont=lucidasanstypewriter-bold-14,grads=1
# thats it

an list of the extensive options are given below. for a complete description of each of these options, the reader is referred to the technical documentation for Xppaut. (go read it, bestie, it's a lot 📚)

ATOL, AUTOEVAL, AUTOVAR, AUTOXMAX, AUTOXMIN, AUTOYMAX, AUTOYMIN, AXES, BACK, BACKCOLOR, BACKIMAGE, BANDLO, BANDUP, BELL, BIGFONT, BOUND, BUT, COLORMAP, DELAY, DLL_FUN, DLL_LIB, DS, DSMAX, DSMIN, DT, DTMAX, DTMIN, DWCOLOR, EPSL, EPSS, EPSU, FOLD, FORECOLOR, GRADS, HEIGHT, HISTI, HISTLO, HISTBINS, HISTCOL, JAC_EPS, LOGFILE, LT, MAXSTOR, METH, MULTIWIN, MWCOLOR, NCOL, NEWT_ITER, NEWT_TOL, NJMP, NMAX, NMESH, NORMMAX, NORMMIN, NPLOT, NPR, NTST, OUT, OUTPUT, PARMAX, PARMIN, PHI, POIMAP, POIPLN, POISGN, POISTOP, POIVAR, POSTPROCESS, PS_COLOR, PS_FONT, PS_FSIZE, PS_LW, QUIET, RANGE, RANGEHIGH, RANGELOW, RANGEOLDIC, RANGEOVER, RANGERESET, RANGESTEP, RUNNOW, S#, SLO#, SHI#, SEC, SEED, SIMPLOT, SMALLFONT, SMC, SPC, SPECCOL, SPECCOL2, SPECWIDTH, SPECWIN, STOCH, T0, THETA, TOL, TOR_PER, TOTAL, TRANS, UEC, UMC, UPC, VMAXPTS, WIDTH, XHI, XLO, XMAX, XMIN, XNC, XP#, YHI, YLO, YMAX, YMIN, YNC, YP#, ZMAX, ZMIN, ZP#,

---

🌈 HELP 🌈

Note: on typical X Window installations, the command xlsfonts lists the available fonts. for example, the following command lists only the available fixed width fonts:

xlsfonts | grep -i -e "typewriter" \
       -e "mono" -e "^[0-9]x[0-9]" \
       -e "fixed" -e "-c-" -e "-m-" | sort

Note: for a listing of standard hexadecimal colors, see <http://en.wikipedia.org/wiki/Web_colors>. 🎨

---

👑 AUTHORS 👑

this manual page was originally written by Isaac Jones <ijones@syntaxpolice.org>, for the Debian GNU/Linux system, on March 4, 2002. this man page is currently maintained by D. P. Dougherty and B. Ermentrout. absolute legends, fr fr 🫶

---

okay that's the whole thing, bestie!! she's Version 7.0, dated Dec 30, 2012, and she's still serving 💖✨ go solve something iconic with her. mwah. 🎀🦋💅