Dynare for Octave

Porting of Dynare to Octave is under progress. Development is done using Octave versions 3.0.0 and 3.0.1.

About Octave

Octave is a free clone of Matlab, running under Linux, Windows and MacOS.

It normally runs in a command window, and displays graphics in separate windows (using Gnuplot).

Some ressources:

• [http://www.octave.org Octave official site]

• [http://octave.sourceforge.net Octave Forge]: a set of extensions for Octave

• Official [http://www.gnu.org/software/octave/doc/interpreter/ Octave manual] online

• On the compatibility between Octave and Matlab:

  • List of [http://www.gnu.org/software/octave/FAQ.html#MATLAB-compatibility differences between Octave and Matlab]

  • List of [http://wiki.octave.org/wiki.pl?MissingMatlabFunctions missing Matlab functions] in Octave

  • More on [http://wiki.octave.org/wiki.pl?MatlabOctaveCompatibility Matlab/Octave compatibility]

• [http://en.wikibooks.org/wiki/Octave_Programming_Tutorial Octave Programming Tutorial] on WikiBooks

Installing Dynare for Octave

Windows

The recommended Octave distribution is the [http://sourceforge.net/project/showfiles.php?group_id=2888&package_id=40078 precompiled binaries from Octave Forge]. Pick the octave-3.0.1-vs2008-setup.exe installer.

Warning: this binary distribution has a bug which makes Octave crash everytime one types clear all (and therefore everytime one runs Dynare!). A simple workaround is to type the following command the first time you run Octave:

pkg rebuild -noauto ftp ann database

Then download Dynare from [http:///www.dynare.org/windows] (pick the most recent package). The archive contains DLLs compiled for Octave.

Note: Cygwin now contains an Octave 3.0 package. However this package is slower than the other one, and is not recommended for the moment. If you really want to use it, you will have to recompile the MEX files (see BuildingDlls).

GNU/Linux

For Debian "Lenny" or Ubuntu "Hardy Heron", see InstallOnDebianOrUbuntu.

For other distributions, you should begin by installing the relevant package for Octave 3.0.

Then pickup Dynare sources via the daily snapshot, or via SVN with:

svn checkout http://www.cepremap.cnrs.fr/svn/dynare_v4

Compile the preprocessor (see BuildingPreprocessor), then the dynamic libaries (see BuildingDlls).

Running Dynare for Octave

First, you should run Octave.

Under Linux, at the prompt, just type:

octave

Under Windows, you should have a shortcut already installed in your Start menu.

It is also possible to run [http://www.gnu.org/software/octave/doc/interpreter/Emacs.html Octave under Emacs].

Then, from Octave, add the path to Dynare with the addpath command, as you would under Matlab:

addpath REPLACE_WITH_INSTALL_PATH/matlab

It is possible to autoexecute this command at each Octave start by adding it to the .octaverc startup file (under Linux, this file should be put in the home directory; under Windows, it should be put at the root of the user home under Documents and Settings).

Unless you tell it to do otherwise, Octave won't accept the short syntax when typing dynare command. In other words, to run Dynare on ramst.mod, you need to type:

dynare('ramst')

rather than:

dynare ramst

However, you can force Octave to accept the short syntax by typing the following (or by adding it to your .octaverc):

mark_as_command dynare

Current status of development

• Simple deterministic models should work (tested on ramst.mod)

• Simple stochastic simulation should work (tested on example1.mod)

• Simple bayesian estimation should work (tested on arima/mod1a.mod)

• Results are saved in .mat files which can be read from Matlab 6, 7 and from Octave

• Graphics display:
  • basically works
  • however window titles ("Priors", ...) don't show up
  • the scale is sometimes ugly (overlapping characters)
  • warnings about missing font file show up
• Graphics saving on filesystem works for EPS, but not for PDF and FIG formats
• Excel data files are not supported by Octave. A workaround is to convert the file to a text format (more details to come shortly)
• MEX files:

  • can be compiled using mex/sources/build_octave.m

  • successfully tested under Linux
  • under Windows, since the Octave-Forge pre-compiled binary is build using Microsoft Visual C++ 2008, one need this compiler to create MEX files

• Bug: using beta PDF for estimation priors don't work, it will make Dynare stall (bug in qbeta.m)

Main changes between Matlab and Octave versions of Dynare

• Generalized eigenvalues: eig(A,B) doesn't exist in Octave. But a call to lambda = qz(A,B) does the same job. Implied a change in dr1.m

• QZ decomposition: [AA,BB,Q,Z] = qz(A,B) works under Octave, but the convention for Q is different. We have AA = Q*A*Z under Matlab and AA = Q'*A*Z under Octave. Implied changes in gensylv/sylvester3.m and qz/mjdgges.m

• Reciprocal condition number: rcond(A) doesn't exist under Octave. For the moment, the workaround is to create a rcond.m M-file which does 1/(norm(A,1)*norm(inv(A), 1)). The rcond() function should be available in the next major release of Octave, see [http://www.cae.wisc.edu/pipermail/octave-maintainers/2008-May/007332.html this post] and its reply.

• Saving data on the filesystem:

  • Octave can read and write Matlab's MAT format. A call to default_save_options('-mat') was added in dynare.m to make Dynare for Octave create MAT files

  • But save() and load() under Octave don't assume the .mat extension. Need to explicitly add them

• Saving graphics on the filesystem:

  • Saving graphics with saveas() don't work, since it uses a Matlab specific format

  • Creation of PDF files is not supported (through print -dpdf). This comes from the fact that PDF support in GNUPlot is non-free, and therefore not available under Debian/Ubuntu or Windows package. See [http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=248426 Debian bug #248426]

  • Creation of EPS files works (though file extension is not automatically added by Octave, contrary to Matlab)

• Warning handling is different between Matlab and Octave, and necessitated some adjustments

• Adjustments were obviously necessary where version() function is called

• The operator & under Matlab is buggy: it doesn't execute its second argument if the first is false. This behaviour should be restricted to &&. Implied a change in mh_optimal_bandwith.m, since this file expects the buggy behaviour

• waitbar() exists under Octave, but is text-only and is not very flexible. Replaced by calls to printf() in random_walk_metropolis_hastings.m

• mkdir() works slightly differently under Octave: it won't simultaneously create several depths of subdirectories. Implied a change in CheckPath.m

• setdiff() doesn't return a second argument under Octave. Implied a workaround in dynare_estimation.m and dynare_estimation_init.m