https://wiki.ncsa.illinois.edu/display/~rhaas/SPIN+2021+Exercise+II

This exercise aims to provide a flavor of the expertise required for the SPIN project as well as giving you an idea of the work expected of you. If you choose to apply to work with me on this project then I will ask you to work through the exercise and send in your results before the interview with me. I provide a worked out solution so you are free to look at it to verify your own solution or to copy and past from it. However please keep in mind that the exercise mostly serves to give you an idea of the skills required to avoid signing up for more than you can handle.

Background

The Laser Interferometer Gravitational-Wave Observatory's (LIGO) detection of gravitational waves from merging black holes in September 2015 inaugurated a new era in astronomy and astrophysics, opening a window to observe the Universe through gravitational radiation. Occurring 100 years after Einstein's announcement of his theory of general relativity, the detection spurred world-wide interest in physics and science in general, making headline news around the world. The recent Nobel Prize awarded for this detection and the announcement of the detection of the double binary neutron star system by LIGO/Virgo underline the importance of these efforts and the interest that the wider society has in it.

Project details

This project is part of the ongoing effort in the NCSA gravity group  to study gravitational waves produced by colliding compact objects like black holes and neutron stars. We use various software tools for this purpose. For simulations on supercomputers we use the Einstein Toolkit computational framework. We have developed a Python code to convert simulation results produced to LIGO injection format files. Part of the conversion is to measure parameters of the waveforms by comparing to post-Newtonian waveforms. This project will aim at two goals:

  • improve speed of Python code used to generate PN waveform
  • improve method used to measure parameters
  • fully integrate multiple Python scripts into a single script

Skills required:

  • knowledge of Python including numerical libraries numpy, scipy
  • some basic numerical analysis knowledge e.g. for root finding

Before applying for this project please work through the exercise available on SPIN 2021 Exercise II as this will be part of the interview with prospective candidates. I will not  consider your application unless I have received the exercise.

Exercise

In this exercise you will use the function scipy.optimize.least_squares to fit a function of the form f(t) = sin(omega * t - phi) to some given data by varying omega and phi.









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