Recent changes

Clawpack is moving to Github and the use of Git for further development work, rather than Subversion. For more details see Development on Github.

Planned changes for Clawpack 5.0

Substantial changes are planned for Clawpack 5.0.

See for more about this, and about plans for other changes.

New in Clawpack 4.6.3

  • This release affects GeoClaw only.
  • The main reason for this release is to fix a bug found in GeoClaw, in the implementation of the friction term. For more details see Manning friction term.
  • A new version of the Okada model and a set of dtopotools have also been included, see Earthquake sources: Fault slip and the Okada model.
  • Other new documentation recently developed for GeoClaw has been incorporated, see GeoClaw.
  • An updated version of $CLAW/apps/tsunami/chile2010 has been included as $CLAW/apps/tsunami/chile2010b.

New in Clawpack 4.6.2

  • OpenMP capability added to amrclaw and geoclaw. See Using openmp for details.
  • Bug fixed in NetCDF output for GeoClaw.
  • NetCDF documentation now exists, see
  • Improved “fixed grid” output in GeoClaw. This allows specification of a fixed grid for output that is independent of what AMR grids are currently in use. The best available data is interpolated to each fixed grid point at each specified output time.
  • Added $CLAW/python/pyclaw/plotters/ to plot fixed grid output. This is not well documented. However, a new version of the fixed grid routines is in the works and documentation will be provided for those in the next release (?).
  • Improved $CLAW/python/pyclaw/plotters/ import setplot more robustly and give a more informative method if there’s a bug in
  • Fixed Makefile.common and Makefiles in $CLAW/apps/tsunami/* to find the *.mod files in $CLAW/geoclaw/2d/lib properly.
  • Documentation added on how to use the Clawpack AMI on Amazon Web Services, see Amazon Web Services EC2 Clawpack AMI.
  • Documentation added on how to set up a GeoClaw run for tsunami modeling, see Quick start guide for tsunami modeling.

Known bugs

  • Conservation is no longer maintained in some examples with periodic boundary conditions. In $CLAW/apps/advection/2d/example/amr and $CLAW/apps/burgers/2d/pwconst/amr mass is conserved to 1e-4 with the parameters as set in, but used to be conserved to roughly 1e-14. This needs to be debugged.

New in Clawpack 4.6.1

Some new capabilities have been added but previous examples should continue to run.

  • NetCDF output can be generated instead of ASCII output, reducing the file size of fort.q files by a factor of 3 or so. Currently this is only available in GeoClaw. Will be ported and documented eventually more generally. For now, see this claw-dev post on NetCDF
  • Restarting an AMRClaw or GeoClaw run is now easier. See this claw-dev post on restarts
  • Some additional book examples have been converted.
  • The plot_topo_file function in $CLAW/python/pyclaw/plotters/ has been improved.


Links below to Trac or the Subversion repository on kingking no longer work. That server died and the backup’s have not been reinstalled eslewhere since development has now moved to

New in Clawpack 4.6.0

This version is still backwards compatible with all of Clawpack except for GeoClaw, where a new version of some AMR library routines have been moved to $CLAW/geoclaw/2d/lib and so changes to the Makefile are required in any GeoClaw applications (such as those in $CLAW/apps/tsunami). See below for more details.

  • Memory reallocation in amrclaw/2d/lib/igetsp.f has been improved so that if doubling the size the work array requires more memory than available, the amount requested will be halved until it fits. This may allow the computation to proceed a bit further.

  • Added capability for ‘other plots’ to be generated and added to html files that are not done each frame. Also added otherplots() method to Iplotclaw.

  • Removed ‘all’ targets from application Makefiles and instead created scripts Modified $CLAW/python/ to first look for such a file and execute it before trying ‘make all’. This avoids warnings that ‘all’ target of Makefile.common is being overloaded, and avoids problems with wrong Makefile being used in recursive makes.

  • New parameter added to GeoClaw input: adding:

    geodata.variable_dt_refinement_ratios = True

    to causes refinement ratios in time on each level to be chosen dynamically, rather than using the ratios specified by clawdata.inratt. The ratios are chosen by estimating the maximum wave speed on each level using a new routine get_max_speed. This is useful for cases where a fine grid only covers cells in very shallow water, in which case it may not be necessary to refine in time as much as in space. It can be hard to estimate in advance what refinement ratio to use for optimal efficiency. This is fairly specific to GeoClaw applications.

    This required making special GeoClaw versions of a few more amrclaw routines, and changes to Makefiles in applications. The script $CLAW/util/ will make these changes.

  • Vectorized routine $CLAW/python/pyclaw/geotools/ that creates seafloor deformation using the Okada model in GeoClaw.

  • Added utility $CLAW/python/pyclaw/geotools/ for converting from MOST format (NOAA’s Method of Splitting Tsunamis code).

  • Added icons to appear in browser tabs for webpages created in Sphinx and by $CLAW/util/

  • Added some documentation on the structure of AMRClaw, provided by Jonathan Claridge. See AMRClaw.

Several other minor changes have been made. Browse the source of branches/4.5.x and examine the changesets for revisions 787-894 for more details.

New in Clawpack 4.5.1

Mostly minor changes from 4.5.0:

  • New phony target output added to $CLAW/util/Makefile.common that does not check dependencies. Now

    $ make output

    always runs the code (but never regenerates the data files using the setrun function!) See Clawpack Makefiles.

  • New phony target plots added to $CLAW/util/Makefile.common that does not check dependencies. Now

    $ make plots

    always creates plots that go in the directory specified by the parameter CLAW_PLOTDIR in the Makefile, using the output that is in the directory CLAW_OUTDIR in the Makefile. It does not remake the output if it is out of date.

  • The targets .output and .plots still exist and function as before.

  • By default, if the directory specified by CLAW_OUTDIR in the Makefile already exists, it is overwritten with new output when you do make .output or make .output. This can now be avoided by setting an environment variable CLAW_OVERWRITE to``False``, or setting this variable explicitly in the Makefile. In this case the current version of the output directory is moved to

  • A new script $CLAW/python/ has been added that compiles all the library routines. It is best to run this before $CLAW/python/ so that the modules created by compiling the library routines end up in the proper place.

  • A new option at the PLOTCLAW> has been added to Iplotclaw:

    PLOTCLAW> save figno fname

    saves figure number figno to file fname using savefig.

  • A number of minor bugs have been fixed, mostly in $CLAW/geoclaw/2d/lib

New in Clawpack 4.5.0


For more details, see below.

  • The svn repository has moved, see below.
  • The main directory name has changed from claw to clawpack.
  • GeoClaw has been added, with a few examples showing how this can be used for tsunami modeling. See GeoClaw added.
  • Some new applications have been added. See Applications gallery for a current list and sample plots.

Subversion repositories and version numbers

We are going to attempt to be more systematic about version numbering and official releases. To aid in the long term development of Clawpack, the Subversion repository at is being phased out and replaced by The tags subdirectory will contain official releases, starting with the various versions of Clawpack 4.4 that have been available in the past as tar files. These are numbered 4.4.0, 4.4.1, etc.

Note that we have introduced a “micro” version number following the major and minor version numbers. Our intention in the future is to mainly use the micro version number for bug fixes and minor changes. New features or more major changes will increment the minor version number (e.g. going from 4.4 to 4.5). Major changes to the structure or functionality will be reflected by incrementing the major version number. Contrary to some conventions, we might not always enforce backward compatibility between minor version numbers.

The trunk should be up to date with the most recent release, so that users who want to use Subversion to keep up to date can check out the trunk and then use “svn update” to stay current:

$ svn co  localdir/clawpack

See the `Clawpack wiki`_ for more details.

The branches subdirectory contains new development branches, including branches such as 4.5.x for updates that will go into the next release, and branches being used to develop or test new features.

Directory structure

Starting in Version 4.5.0, the main directory is called clawpack. The location of this directory is where the environment variable $CLAW should point and this convention will be used below. Within this directory, the structure is currently unchanged.

In Version 5.0 we intend to further rearrange directories. All the Fortran source code will go in $CLAW/src and we plan to introduce a $CLAW/lib for dynamic libraries. The Makefiles will also change to reflect these changes.

GeoClaw added

The GeoClaw routines are now incorporated in Clawpack. Some documentation is in the section GeoClaw.

The main library routines for 2d depth-averaged flow are in $CLAW/geoclaw/2d/lib.

A few examples are in $CLAW/apps/tsunami. See the gallery of sample GeoClaw results.

The GeoClaw software uses modules and the Makefiles don’t always work properly yet. If you run into problems, try:

$ make new

in the applications directory.

New in Clawpack 4.4


Clawpack 4.4 consists of the Fortran 77 files from Clawpack 4.3 together with new Python tools for specifying input data and plotting results.

There is also a preliminary version of a pure Python version of Clawpack, see Pyclaw.

Summary of major changes

  • The classic clawpack routines now read data from a file

  • rather than and the first line of this file lists the number of space dimensions. The remainder of the file has the same form as before.

  • Rather than modifying it is recommended that you modify parameters in the file and then type

    $ make .data

    to create the file. You can modify this to also create or other required data files.

  • The matlab plotting scripts should still work as described in the 4.3 documentation, but there is now a Python option that uses only open source software and provides more powerful plotting tools. See Plotting options in Python.

  • The output routines such as out1.f, out2.f in classic Clawpack and valout.f in AMRClaw have been slightly modified to also print ndim to the fort.t files. This should not affect Matlab plotting but is needed for the new Python plotting routines.

Changes since 4.4.0

  • 10/30/09: Several more changes to Makefiles and amrclaw/2d/lib.

    • This version posted as claw4rev226.tar.gz
    • The subroutines filpatch and prefil are now written as recursive subroutines, so filpatch2.f, filpatch3.f, prefil2.f, and prefil3.f have been removed. Also drawrg.f has been removed, an old NCAR graphics routine no longer used. Makefiles in any amr application directory will need to be changed to remove these files from the list.
    • For some samples of how to use the latest amrclaw, see e.g.,
  • 10/20/09: Several changes to Makefiles and amrclaw/2d/lib.

    • A new $CLAW/apps directory has been added for applications. The ones there now are ones used to debug the amrclaw changes, but eventually many more applications from Clawpack 4.3 and elsewhere will be put here.
    • New options added to the common Makefile in util/Makefile.common. Type “make help” for a list. Makefiles can now also check for dependencies of included files such as call.i used in AMR.
    • New boundary conditions added to amrclaw for problems on the sphere,
    • Dynamic memory for amrclaw - the subroutine init_alloc.f95 was split up into:
    • init_alloc.f90 does initial allocation and the initial size of the work array for AMR is specified here.
    • resize_alloc.f90 reallocates for dynamic memory allocation if the code runs out of space for AMR.
    • resize_alloc_static.f90 halts with an error message instead of reallocating. For use with compilers that don’t support move_alloc, such as older versions of gfortran. This is recommended as the default version in application Makefiles since otherwise it might not compile. Note that some f90 compatible compiler is required for using AMR (e.g. gfortran, which is freely available).
    • restart_alloc.f90 is needed when doing a restart with dynamic memory.
    • Note that .f95 files are now relabelled as .f90 since this is apparently the standard.
    • Note that Makefiles in user directories that use amrclaw will need to be updated to list init_alloc.f90 and resize_storage_static.f90 or resize_storage.f90.
    • Several bug fixes in amrclaw/2d/lib
  • 9/18/09: branches/rjl merged back into trunk, includes:

    • Improvements to plotting routines and documentation,

    • More converted examples in the book directory,

    • clawpack/2d/lib directory added with 2d single-grid routines.

      Similar to version from Clawpack 4.3 but can use to set runtime parameters and data file is now called

      See clawpack/2d/example1 for an example of usage.

    • amrclaw/2d/lib directory added.

      Similar to the version in Clawpack 4.3, but with some f95 routines to support dynamic memory allocation. Also gauges are implemented in this version (documentation to appear).

      See clawpack/2d/example1/amr for an example of usage.