# Meep release notes

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Here, we describe what has changed between releases of the Meep package. You can also refer to the NEWS file in the Meep package (or the ChangeLog file for a more detailed listing).

## Meep 0.20.3

24 July 2008

• Fixed circular dependency in Makefile, which caused problems with some versions of make; thanks to Kaoru Narita for the bug report.

## Meep 0.20.2

21 July 2008

• Fixed incompatibility with Guile 1.6.x or earlier; thanks to the bug report by Andreas Unger.

## Meep 0.20.1

21 July 2008

• Improved handling of nested synchronized-magnetic calls.
• Bug fix: parallel builds (make -j) should now work.
• Bug fix: pkg-config file was incorrectly installed for MPI version; thanks to Majid Sodagar for the bug report.

## Meep 0.20

19 July 2008

• Support for user-specified permeability (mu). Renamed "dielectric" to "medium" in libctl interface, new "mu" property and new output-bfield and output-mu functions, and new "Permeability" and "Bx" etc. field types.
• Support for user-specified electric and/or magnetic conductivities. These are especially useful to add a desired dissipation loss (an imaginary part of ε/μ) in a narrow bandwidth, without messing around with Lorentzian dispersive materials.
• Add predefined perfect-magnetic-conductor (μ = −∞) material, along with perfect-electric-conductor (ε = −∞).
• Added synchronized-magnetic step function to allow step functions to run with the electric and magnetic fields synchronized in time to second-order accuracy.
• New PML implementation (UPML instead of split-field), should have lower reflection in many cases.
• User-specified PML profile and asymptotic reflection.
• Internally, all timestepping code is now handwritten (and much shorter) rather than old verbose Haskell-generated code; this should make it easier to add new features.
• Add support for non-integrated current sources, if the is-integrated? property of the current is set to false; this is now the default, to make handling of E and H sources more similar and intuitive.
• Work with HDF5 1.8 (which previously would not compile unless you manually set a preprocessor flag, due to API changes).
• Check for ctl.h in /usr/include/ctl/ctl.h (default in Fedora), and check for libctl in /usr/share/libctl3 (default in Debian & Ubuntu).
• Bug fix: fixed relative phase of E and H sources (which were off from one another by half a timestep); thanks to M. Megens for bug report.
• Bug fix: make sure h5 filenames have unique timestep for cases where Δt is very small or very large.

## Meep 0.10.1

13 November 2007

• Bug fix in flux_in_box, which accidentally returned the flux multiplied by the number of processors, instead of the flux.
• Bug fix in epsilon averaging for structures including metals (ε < 0), fixing an instability.
• Bug fix in output-png when running in parallel (removing race condition).
• Fixed bug that disabled subpixel averaging for dimensions=1 (thanks to Mischa Megens for the bug report).
• Fixed bug that caused output-tot-pwr to stop Meep with an error message; thanks to Vyacheslav Sokolov for the bug report.
• Make at-every step functions less susceptible to rounding errors; thanks to L. Le Guyader for the bug report.
• Fixed bug in dispersive media that wasted memory on parallel machines (the polarization memory was not parallelized); thanks to J. L. Silva for the bug report.
• Bug fix in output-png+h5, thanks to a report by Chad Husko.
• Fixed several deadlocks that could occur when the parallel Meep is used with a serial HDF5 library (we continue to recommend using the parallel HDF5 library with parallel Meep, however). Thanks in part to Lingling Tang for his bug report.
• For maintainer-mode, improved detection of Haskell package names; thanks to Liang Huo for the bug report.

## Meep 0.10

21 August 2006

• eps-averaging? is now turned on by default (in libctl interface), using much-improved algorithm by Ardavan Farjadpour. This greatly improves accuracy, and also allows continuous tuning of geometric parameters. (See our upcoming paper in Optics Lett., with a preprint at Citing Meep.) New input variables subpixel-tol and subpixel-maxeval to control the accuracy of the subpixel averaging.
• Support for χ(2) (Pockels) as well as χ(3) (Kerr) nonlinearities.
• Symmetries no longer require the cell size to be an even number of pixels. Previously, Meep exited with an error in this case, whereas now it simply adds an extra pixel to the cell size as needed.
• New with-prefix step function to allow you to use a different filename-prefix for selected outputs.
• New feature for output-png: built-in shell variable \$EPS that refers to the last-output epsilon .h5 file, which you can use to easily add dielectric contours/overlays to the field output image.
• Added output-png+h5 function that outputs both .png and .h5 files.
• New functions flux-in-box, electric-energy-in-box, magnetic-energy-in-box, and field-energy-in-box (convenience wrappers around C++ functions).
• Bug fix in Kerr nonlinearity: chi3 was accidentally scaled by $\varepsilon^4$ factor.
• Bug fix: if you specified three or more symmetries, at most two symmetries were used (ignoring the rest).
• Bug fix in rotate2 symmetry, which wasn't working correctly.
• Bug fix in add-flux for multiple flux regions, thanks to K. Choi.
• Bug fix in harminv where it wouldn't allow you to call harminv more than once for the same run loop; thanks to Aristos Karalis.
• Bug fix in save-flux/load-flux that prevented it from working properly without output directories, thanks to Karl Koch.
• Fixed abort that sometimes occurred due to rounding when the source was the same width as the cell (thanks to G. J. Parker).
• Fixed minor build problems on Cygwin, SGI, and other systems, thanks to Christopher Kang, Robyn Landers, Florencio Garcia, and others.

## Meep 0.9

1 April 2006

• Initial public release.