This repository contains a few applications for Cholesky Decomposition using the S-Net coordination language.

Generates an input file for Cholesky Decomposition. The output file consists of the lower triangle of a symmetric positive definite matrix.

Usage: ./symposdef [N] [-d] [-v] [-o outfile] [-t trifile]

Where N is the matrix size, outfile gives the file for the symmetric positive definite matrix, and trifile will receive the lower triangle of decomposed matrix. Make sure this application is compiled with maximum optimization as matrix sizes beyond 4096 may take many minutes to complete.

Single is a single-threaded application to do Cholesky Decomposition. One nifty feature is that it can generate dataflow dependency graphs for the decomposition computations. A generated graph is in Dot format. It can be converted to PNG image file format as follows:

dot -Nmargin=0 -Granksep=0.2 -Gmindist=0.1 -Gnodesep=0.2 -Nheight=0.1 -Nwidth=0.1 -Grankdir=TB -Nstyle=filled -Tpng -O ./single-graph-output.dot

Decompose is an S-Net application to do multi-threaded Cholesky Decomposition, which fully exposes all concurrency to the hardware. Whenever a box function has computed a new tile it sends this tile to the appropriate destination synchro-cells, which are indexed using multiple index split combinators. The S-Net source uses a feedback combinator for efficiency reasons. It reads the input matrix from a file.

Is similar to decompose. The difference here is that it uses a star combinator. It is slightly slower than decompose.

Is a handy script to start either of decompose or decompose2. It generates the required input record.

Usage: ./run [ N B inputfile outputfile ./executable -options ]

Is similar to the run script. It generates a new input record according to provided commandline parameters.

Usage: ./gen [ N B inputfile outputfile ]

This directory contains several interesting dataflow graphs for different P factors, where P = N / B. In addition the corresponding PNG files are given.

The S-Net applications require a recent snet-rts from git@github.com:gijsbers/snet-rts.git. This contains two important bugfixes for reference counting. The provided Makefile depends on some new features in the current snetc, as of June 2013, from the SVN repository.

Does speedup measurements. Adapt to local machine!

Does maximum performance measurements. Adapt to local machine!