Issue I497 [enhancement,example,sds,resolved] SDS atmospheric pressure collision model (sds). This example was added in 8.0.3. As of 20080424, significant enhancements have been made: REV-3 some code restructuring renamed adjustable variables (now with SDS_ prefix). new SDS_enable variable New install() function and options opt. remove skip if "ion_instance ~= 1" in other_actions. REV-4b significant restructuring major code structure/quality improvements (without affecting calculation) pressure/temperature/velocity can now be defined via an analytical function. allow SDS to be disabled on certain instances numbers (i) via SDS.instances[i] = false. Fixed wb_orient_to_pa_orient -> pa_orient_to_wb_orient (this mistake was introduced in the port from the PRG code. The error only existed when using velocity arrays on a PA that was rotated from the original WB coordinates.) Allow vz component in velocity array even in 2D planar arrays. REV-4c 2008-04-26 More minor code quality improvements Fixed "point_weights = sfx*fy*fz" -> "... sfx*fy*sfz". Error was introduced in conversion from PRG and only has a minor effect on 3D arrays. Support P/T/v arrays using real SIMION PAs (8.1 mode only). Add SDS.velocity_coords parameter. REV-4d 2008-05-08 Added print_sds_parameters function (adrian-20080508) REV-4e 2008-05-08 simion.VERSION check corrected in check_array test3.lua - unload PAs from previous runs.