DIRSIG

According to the webpage, DIRSIG4 is currently only supporting Solaris/SPARC 2.9+ and Linux/x86 2.4 kernels. The next set of releases (dirsig-3.6.5 and dirsig-4.0.7) will come with experimental support for the x86-64 platform. Internally, we have a cluster of Athlon64 machines running Fedora Core 5. The added registers on the 64-bit x86 architecture give a significant speed boost over the 32-bit counterpart. The biggest issue with supporting new platforms is packaging the end product. Solaris is a particular pain because users are poor at keeping their installations up to date. There are still people out there using Solaris 8 when the current OS version is Solaris 10. Another issue is which version of LAM MPI to use for the Linux builds. The key contenders are 7.0.6 and 7.1.2. Most of our userbase tend to have older OS setups, so we will probably use the former.

It occurred to me that the ODB instancing can be used on both solid geometry and voxelized grids. Among other things, this means that grids no longer need to be axis-aligned. Simply stick the solid geometry or grid in a separate ODB file and instance it using the technique discussed in Instancing ODBs .

Another feature coming in DIRSIG 4.0.6 is support for regular voxelized grids. The advantage of these structures is that they allow for extremely fast intersections of regularly spaced boxes. The backend code for implementing these grids is also used by DIRSIG to implement support for the QUIC concentration map outputs. In the ODB file: REGULAR_GRID { INSERT_POINT = 0,0,0 DELTA_X = 20 DELTA_Y = 10 DELTA_Z = 25 GRID_FILENAME = niek.grid } The INSERT_POINT indicates a grid extent, the point with the smallest x,y,z coordinate values. DELTA_X/Y/Z indicates the size, in meters, of each voxel. The GRID_FILENAME indicates where the voxel data is stored. Note that the .grid extension is not required. The contents of the .grid file are as follows: 10 10 10 9 9 0 13 230 0 9 8 0 13 230 0 9 7 0 13 230 0 The first line indicates the number of boxes in the x, y, and z direction. For

The DIRSIG team is working with Los Alamos National Laboratory (LANL) to integrate the Qwick Urban industrial Complex (QUIC) plume model in to DIRSIG. Starting with version 4.0.6, the functionality to read in a QUIC gas concentration output will be available. The functionality is currently experimental, and the syntax is liable to change in future DIRSIG revisions. An example of an NH 3 plume: PLUME { QUIC_INSTANCE { CONCENTRATION_MAP = quic.dat MOLECULAR_WEIGHT = 17.03 MATERIAL_ID = 5 RELEASE_TEMPERATURE = 550 INSERT_POINT = 0,0,0 GRID_OFFSET = 3,3,0 DELTA_X = 1.0 DELTA_Y = 1.0 DELTA_Z = 1.0 } } The CONCENTRATION_MAP indicates the QUIC output file. The MOLECULAR_WEIGHT allows DIRSIG to convert from the [g/m 3 ] used by QUIC to the [ppm] used by DIRSIG. The MATERIAL_ID gives the entry in the materials database supplying the radiometric and thermal properties of the gas. The RELEASE_TEMPERATURE, in kelvin, is a hack, compensa