[Back to B.T. Draine's home page.]
[Last updated 2009.03.09] Scattering and Absorption of Light by Small Particles

The Discrete Dipole Approximation for Scattering and Absorption of Light by Irregular Particles

DDSCAT 7.0

DDSCAT, a Fortran code for calculating scattering and absorption of light by irregular particles, has been jointly developed by Bruce T. Draine (Dept. of Astrophysical Sciences, Princeton University) and Piotr J. Flatau (Scripps Institution of Oceanography, UCSD). The current version is DDSCAT 7.0, which supersedes previous versions. DDSCAT 7.0 can calculate scattering and absorption by isolated particles (e.g., dust grains) but can also calculate scattering and absorption by one- and two-dimensional arrays of "target unit cells" that may have complex geometries (Draine & Flatau 2008); this has obvious applications to photonics and studies of arrays of nanostructures.

DDSCAT 7.0 is publicly available (see below), and is now considered to be the standard version of DDSCAT. If you choose to use it, please send email to <draine@astro.princeton.edu> "registering" as a user; registered users of DDSCAT will be notified when updates to the code are made.

If you publish results obtained with DDSCAT 7.0, please cite the following references:

  • Draine, B.T., & Flatau, P.J., "Discrete dipole approximation for scattering calculations", J. Opt. Soc. Am. A, 11, 1491-1499 (1994) (pdf)
  • Draine, B.T., & Flatau, P.J., "User Guide to the Discrete Dipole Approximation Code DDSCAT 7.0", http://arXiv.org/abs/0809.0337v5 (2008)

    and, if you carried out calculations for periodic structures:

  • Draine, B.T., & Flatau, P.J., "Discrete-dipole approximation for periodic targets: theory and tests", J. Opt. Soc. Am. A, 25, 2593-2703 (2008) (pdf)

    User Guide for DDSCAT.7.0

    An extensive User Guide is available: "User Guide to the Discrete Dipole Approximation Code DDSCAT.7.0", by B.T. Draine and Piotr J. Flatau. A copy of this document (postscript or pdf) can be obtained from arXiv/0809.0337v5 and can be cited as

    Downloading the DDSCAT 7.0 Code

    A single distribution is provided for DDSCAT 7.0 -- by appropriate editing of the Makefile, this distribution can be used to generate executables using either single- or double-precision arithmetic; either without or with MPI capability; either without or with OPENMPI support; and either without or with the Intel MKL library.

    To download, click here: ddscat7.0.7.tgz to obtain a gzipped tarfile containing complete source code and documentation for DDSCAT 7.0, including the programs DDfield and CALLTARGET..

    DDSCAT Wikidot

    Additional information about using DDSCAT can be found at the DDSCAT Wikidot.

    Downloading executables for Windows Vista

    Pre-compiled DDSCAT binaries for Windows Vista may be available at http://ddscat.wikidot.com/download, together with some information regarding using the binaries under Windows Vista.

    History of recent releases:

  • DDSCAT 7.0 was first released 2008 September 3. The latest version is dated 2008.10.28
  • DDSCAT 6.1 was released 2004 September 10. [NOTE: as of 2008.09.02, DDSCAT 6.1 is no longer supported.]
  • DDSCAT.6.0 was released 2003 September 2. [NOTE: as of 2004.09.10, DDSCAT 6.0 is no longer supported.]
  • DDSCAT.5a10 was released 2000 August 9. [NOTE: as of 2003.09.02, DDSCAT.5a10 is no longer supported.]
  • DDSCAT.5a9 was released 1998 December 23. It fixes a bug in DDSCAT.5a8, which resulted in incorrect evaluation of elements of the Mueller scattering matrix (other than S_11, which was correct) for scattering planes other than phi=0.

    Benchmark Calculations

    Draine (2000) has published benchmark calculations for scattering by tetrahedral targets. Two target refractive indices have been considered: m=1.33+0.01i and m=1.70+0.10i . Scattering was calculated for one target orientation and two incident polarizations. In each case solutions were iterated until the DDA equations were satisfied with a fractional error < 1.e-5 . CPU times are reported below for a 600 MHz Pentium III system running Red Hat Linux 6.2, using the Portland Group pgf77 compiler.

    CPU time (s) on 600 MHz Pentium III System

    m=1.33+0.01i tetrahedron
    N x=5 x=10 x=15
    4030 31. -- --
    13426 141. 267. --
    31598 356. 639. 1106.
    61432 792. 1480. 2476.
    105832 1298. 2292. 4226.
    m=1.7+0.1i tetrahedron
    N x=5 x=10
    13426 377. --
    31598 939. 2104.
    61432 2115. 4429.
    105832 3585. 7335.

    For users wishing to repeat one or more of these calculations using DDSCAT.5a10 (which may be useful to reassure you that DDSCAT.5a10 is working properly on your computer), sample ddscat.par files are available for downloading:

    Please consult the DDSCAT UserGuide (see above) for an explanation of the parameters in the ddscat.par file.

    For additional information on other techniques for numerical calculation of electromagnetic scattering by finite targets, see also the SCATTERLIB library of light scattering codes maintained by Piotr Flatau.

    Downloading DDSCAT 6.1

    Please note that DDSCAT 6.1 is no longer considered to be "supported" -- please switch to using DDSCAT 7.0 . However, we continue to make available two distributions of DDSCAT 6.1. Both include bug fixes (see below) up to and including 2008.06.23 (at this time we are not aware of any bugs in the DDSCAT 6.1 code):

    User Guide for DDSCAT.6.1

    We continue to make available the UserGuide to the previous version of DDSCAT: "User Guide to the Discrete Dipole Approximation Code DDSCAT.6.1", by B.T. Draine and Piotr J. Flatau. A copy of this document (postscript or pdf) can be obtained from astro-ph/0409262 (gzipped postscript) or astro-ph/0409262 (pdf) and can be cited as Back to B.T. Draine's home page.