Found 52 talks archived in Computing

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Thursday February 26, 2009
Dr. Ángel de Vicente
Instituto de Astrofísica de Canarias, Spain

Abstract

If you do any amount of programming, you have certainly found that at some point during its development your code did not work as expected. Perhaps it simply crashed and told you that a core dump was created; perhaps it always gave you an "incorrect" result or perhaps it just behaved "oddly" given some input combinations. In any case, you were face to face with a "bug". And what did you do to correct your code? If the answer was to put "printf"s around the code and run it again, you should attend this talk in which we'll see an introduction on how to debug your programs with a debugger. The debugger (available for most programming languages) is a really easy-to-use tool that lets you run your application in a special mode, so that you can run it step by step, or stop at certain points, inspect variables, etc., which is a great aid to find what is wrong with your code without the need of changing its source.

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Thursday November 13, 2008
Prof. Simon White
Max-Planck Institut für Astrophysik, Garching, Germany

Abstract

In our now-standard picture for the growth of structure, dark matter halos are the basic unit of nonlinear structure in the present Universe. I will report results from simulations of galaxy-scale dark halos with more than an order of magnitude better mass resolution than any previously published work. Tests demonstrate detailed convergence for (sub)structures well below a millionth the mass of the final system. Even with such resolution the fraction of halo mass in bound subhalos does not rise above a few percent within the half-mass radius. I will also present a new simulation technique which allows structure in the dark matter distribution to be studied on very much smaller scales. This is required for accurate forecasts of the expected signal both in earth-bound experiments designed to detect dark matter directly, and in indirect detection experiments like GLAST which attempt to image dark matter annihilation radiation at gamma-ray wavelengths.