Line-by-line spectroscopic simulations on graphics processing units

We report here on software that performs line-by-line spectroscopic simulations on gases. Elaborate models (such as narrow band and correlated-K) are accurate and efficient for bands where various components are not simultaneously and significantly active. Line-by-line is probably the most accurate model in the infrared for blends of gases that contain high proportions of H2O and CO2 as this was the case for our prototype simulation. Our implementation on graphics processing units sustains a speedup close to 330 on computation-intensive tasks and 12 on memory intensive tasks compared to implementations on one core of high-end processors. This speedup is due to data parallelism, efficient memory access for specific patterns and some dedicated hardware operators only available in graphics processing units. It is obtained leaving most of processor resources available and it would scale linearly with the number of graphics processing units in parallel machines. Line-by-line simulation coupled with simulation of fluid dynamics was long believed to be economically intractable but our work shows that it could be done with some affordable additional resources compared to what is necessary to perform simulations on fluid dynamics alone.Program summaryProgram title: GPU4RECatalogue identifier: ADZY_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZY_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 62 776No. of bytes in distributed program, including test data, etc.: 1 513 247Distribution format: tar.gzProgramming language: C++Computer: x86 PCOperating system: Linux, Microsoft Windows. Compilation requires either gcc/g++ under Linux or Visual C++ 2003/2005 and Cygwin under Windows. It has been tested using gcc 4.1.2 under Ubuntu Linux 7.04 and using Visual C++ 2005 with Cygwin 1.5.24 under Windows XP.RAM: 1 gigabyteClassification: 21.2External routines: OpenGL (http://www.opengl.org)Nature of problem: Simulating radiative transfer on high-temperature high-pressure gases.Solution method: Line-by-line Monte-Carlo ray-tracing.Unusual features: Parallel computations are moved to the GPU.Additional comments: nVidia GeForce 7000 or ATI Radeon X1000 series graphics processing unit is required.Running time: A few minutes.