Toldiff is a diff tool that allows tolerable (insignificant) differences between two files to be suppressed showing only the important ones. The tolerable differences are recorded running the tool with an appropriate command line flag.
The Collaborative Testing System (CTS) tests parallel software using various implementations of MPI. It works on multiple platforms and supports batch systems including LSF, LCRM and workstations without a batch system. It includes a numerical diff tool.