In this podcast, the Radio Free HPC team discusses a recent presentation by John Gustafson on Next Generation Computer Arithmetic. “A new data type called a “posit” is designed for direct drop-in replacement for IEEE Standard 754 floats. Unlike unum arithmetic, posits do not require interval-type mathematics or variable size operands, and they round if an answer is inexact, much the way floats do. However, they provide compelling advantages over floats, including simpler hardware implementation that scales from as few as two-bit operands to thousands of bits.”
“This tutorial will present several features that the draft Fortran 2015 standard introduces to meet challenges that are expected to dominate massively parallel programming in the coming exascale era. The expected exascale challenges include higher hardware- and software-failure rates, increasing hardware heterogeneity, a proliferation of execution units, and deeper memory hierarchies.”
“OpenMP, Fortran 2008 and TBB are standards that can help to create parallel areas of an application. MKL could also be considered to be part of this family, because it uses OpenMP within the library. OpenMP is well known and has been used for quite some time and is continues to be enhanced. Some estimates are as high as 75 % of cycles used are for Fortran applications. Thus, in order to modernize some of the most significant number crunchers today, Fortran 2008 should be investigated. TBB is for C++ applications only, and does not require compiler modifications. An additional benefit to using OpenMP and Fortran 2008 is that these are standards, which allows code to be more portable.”
“Fortran has been proven to be extremely resilient to new developments that have appeared in other programming languages over the years. New versions continue to be available and associated with ANSI standards, so that an application written for one operating system should be able to be compiled and run with different compilers on different operating systems. The latest version is Fortran 2008, with the next version reportedly to be available as Fortran 2015, in 2018.”
Originally developed by IBM in the 1950s for scientific and engineering applications, Fortran came to dominate this area of programming early on and has been in continuous use for over half a century in computationally intensive areas such as numerical weather prediction, finite element analysis, computational fluid dynamics, computational physics and computational chemistry. It is a popular language for high-performance computing and is used for programs that benchmark and rank the world’s fastest supercomputers.
In this special guest feature from Scientific Computing World, Andrew Jones from NAG looks ahead at what 2016 has in store for HPC and finds people, not technology, to be the most important issue. “A disconcertingly large proportion of the software used in computational science and engineering today was written for friendlier and less complex technology. An explosion of attention is needed to drag software into a state where it can effectively deliver science using future HPC platforms.”
Today the NNSA and its three national labs announced they have reached an agreement with Nvidia’s PGI software to create an open-source Fortran compiler designed for integration with the widely used LLVM compiler infrastructure.
Fortran still going strong. NERSC estimates that over half the hours on their systems are used by Fortran codes. This is quite amazing, given that Fortran first appeared about 60 years ago.