SIMTOI is a general-purpose model fitting program for optical interferometry. It is designed to model complex astrophysical sources whose analytic Fourier transform is not easily computed. SIMTOI leverages the Open Graphics Language (OpenGL) and the Open Compute Language (OpenCL) to convert and compare its 3D, time- and wavelength-dependent models with several different types of data. SIMTOI can be used for simulation, visualization, minimization, and model selection problems.

SIMTOI v1.0 screenshot

SIMTOI is developed by Dr Brian Kloppenborg of Georgia State University and distributed under an open source (GPL v3) license. If you encounter bugs, please file a report on the issue tracker. If you have specific requests for additional features, models, or other enhancements, please send an email To Brian (contact information on the SIMTOI project page). If you use SIMTOI for your work, please acknowledge it per the guidelines on the project's webpage.

Features

For a complete, up-to-date list of features, see SIMTOI's homepage on GitHub

Stellar models

  • Uniform disk
  • Several limb darkening models including Claret (2000), Fields (2003), logarithmic, power law, quadratic, and square root.
  • Oblate spheroids with gravity darkening
  • Roche surfaces
  • Spots

Astrophysical disks

  • Power law density profile in both radius and height (c.f. Pascucci et al. 2004)
  • Power law density profile in both radius and height with an exponential taper at large radii (c.f. Andrews et al. 2009)

Model positioning

  • Static (x,y,z)
  • Keplerian orbit

Supported data types:

  • Optical interferometric V2, T3 (amplitude and phase)
  • Broadband photometry

Minimization Engines:

  • Levmar (Levenberg-Marquardt optimization algorithm)
  • Gridsearch
  • MultiNest (Bayesian nested sampling, model selection)

Other features:

  • Live parameter updating, model rendering, and data computation.
  • Model animation
  • Command line options. Easily scripted using Python
  • Easily edited JSON save files
  • Runs locally on your computer (unlike JMMC's litpro)

System requirements, downloading and installing

SIMTOI is designed to be cross-platform compatible. It has been tested on several variants of GNU/Linux and on Mac OSX 10.8. Test on additional platforms are most welcomed.

SIMTOI requires that your computer have a graphics processor that supports OpenCL 1.0 (or higher) and OpenGL 3.3 (or higher). Almost any discrete graphics card by nVidia or ATI/AMD will meet these requirements. Intel integrated graphics provided by Fourth generation Intel processors (i.e. i3/5/7-4xxx) is presently experimental.

See SIMTOI's homepage on GitHub for the latest requirements and installation instructions.