Present and Future Computing, Data, and Networks Committee of the Canadian Astronomical Society (CASCA)
This document is a whitepaper I wrote for the CASCA Computing and Data committee outlining the computing needs for the Canadian astronomy community for the coming several years. It does a fairly decent job of laying out the diverse range of large-scale R&D computing needs for the national community. Executive Summary Advanced research computing resources have never been so essential to the Canadian Astronomy and Astrophysics research community. In the past few years, astronomical researchers have benefited greatly from modern large-scale computing systems; a diverse...
Continue...Stopping your program at the first NaN
If you know that somewhere in your program, there lurks a catastrophic numerical bug that puts NaNs or Infs into your results and you want to know where it first happens, the search can be a little frustrating. However, as before, the IEEE standard can help you; these illegal events (divide by zero, underflow or overflow, or invalid operations which cause NaNs) can be made to trigger exceptions, which will stop your code right at the point where it happens; then if you run your...
Continue...Testing Roundoff
A talk has been circulating (HT: Hacker News) from a conference celebrating 50 years of scientific computing at Stanford where the author, William Kahan, discusses an old and sadly disused trick for testing the numerical stability of the implementation of an algorithm that should work with any C99 or Fortran 2003 compiler without changing the underlying code. It’s definitely a tool that’s worth having in your toolbox, so it’s worth mentioning here. We’ll consider a simple numerical problem; imagine a projectile launched from height $h...
Continue...Codes as Instruments: Community Applications and Simulation Software for the Hardware Architectures of the Next Decade
It is becoming increasingly problematic that, even as computing and data becomes more and more fundamental to research, and the complexity and diversity of computing technologies out there grows, getting stable funding for developing high-quality research software remains so difficult. In this whitepaper for the CASCA 2010 Long Range Plan, my colleague Falk Herwig and I lay out the case for increased funding of R&D software development by professional research software developers. We make a couple points which I genuinely believe to be strong: First,...
Continue...Canadian Astronomical Computing, Data And Network Facilities: A White Paper for the 2010 Long Range Plan
In this whitepaper for the CASCA 2010 Long Range Plan, I and the rest of the Computing, Data, and Network committee of CASCA lay out the state of ecosystem for computation in support of Canadian astronomy, and suggests a path forward for the time period of the 2010-2020 long range plan. Abstract Significant investment in new large, expensive astronomical observing facilities spanning a substantial portion of the electronic spectrum was a dominant theme of LRP2000 and continues to be necessary for Canadian astronomy to maintain...
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