The Density Matrix Renormalization Group (DMRG) is a numerical method used to solve models of strongly correlated electronic materials. These models simulate quantum many-body systems in condensed matter theory. The DMRG method uses a relatively modest amount of computational power, and yet, its accuracy is comparable to exact methods, at least for one-dimensional and quasi- one dimensional geometries. Since 1992, when first proposed by S. R. White, the DMRG algorithm has been used by many physicist andchemists.
DMRG++ is ORNL's implementation of the DMRG algorithm in the C++ programming language.An input file with the model parameters is needed to start the computational code. This file is written in plain text format, making it difficult to find and report errors. Therefore, a new format for the input file, the JSON format which stands for  JavaScript object notation, was developed, and changes to the code were made to accept this new format. In addition, a Perl (Practical Extraction and Reporting Language) scriptwas written to convert existent plain text input files to the new JSON format. The JSON format will help detecting errors in the input file, and will facilitate runs on high-end computational systems.
jesus torres,
Aug 12, 2011, 8:18 AM