SuiteSparse is a suite of sparse matrix algorithms, including: UMFPACK(multifrontal LU factorization), CHOLMOD(supernodal Cholesky, with CUDA acceleration), SPQR(multifrontal QR) and many other packages.

Software Refresh

OSC timely installs new software versions on OSC systems, and periodically do coordinated software refresh (update the default versions to be more up-to-date and remove some versions that are quite out of date) on OSC systems. While we encourage everyone to use up-to-date software, the old defaults will still be available till the next software refresh, in case some users prefer to use the old defaults. The software refresh is usually made during the scheduled downtime, while we will send out notifications to all users ahead of time for any questions/suggestions/concerns.


There are many instances where it is necessary to run the same serial program many times with slightly different input. Parametric runs such as these either end up running in a sequential fashion in a single batch job, or a batch job is submitted for each parameter that is varied (or somewhere in between.) One alternative to this is to allocate a number of nodes/processors to running a large number of serial processes for some period of time. The command parallel-command-processor allows the execution of large number of independent serial processes in parallel.

GNU Compilers

Fortran, C and C++ compilers produced by the GNU Project. 

Availability and Restrictions


GNU compilers are available on all our clusters. These are the versions currently available:


PnetCDF is a library providing high-performance parallel I/O while still maintaining file-format compatibility with  Unidata's NetCDF, specifically the formats of CDF-1 and CDF-2. Although NetCDF supports parallel I/O starting from version 4, the files must be in HDF5 format. PnetCDF is currently the only choice for carrying out parallel I/O on files that are in classic formats (CDF-1 and 2). In addition, PnetCDF supports the CDF-5 file format, an extension of CDF-2, that supports more data types and allows users to define large dimensions, attributes, and variables (>2B elements).


Q-Chem is a general purpose ab initio electronic structure program. Its latest version emphasizes Self-Consistent Field, especially Density Functional Theory, post Hartree-Fock, and innovative algorithms for fast performance and reduced scaling calculations. Geometry optimizations, vibrational frequencies, thermodynamic properties, and solution modeling are available.


Boost is a set of C++ libraries that provide helpful data structures and numerous support functions in a wide range of aspects of programming, such as, image processing, gpu programming, concurrent programming, along with many algorithms.  Boost is portable and performs well on a wide variety of platforms.

HOWTO: Use ulimit command to set soft limits

This document shows you how to set soft limits using the ulimit command.

The ulimit command sets or reports user process resource limits. The default limits are defined and applied when a new user is added to the system. Limits are categorized as either soft or hard. With the ulimit command, you can change your soft limits for the current shell environment, up to the maximum set by the hard limits. You must have root user authority to change resource hard limits.