Author Archives: Chris Paciorek

NIMBLE is hiring a programmer

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This position includes work to harness parallel processing and automatic differentiation, to generate interfaces with other languages such as Python, to improve NIMBLE’s scope and efficiency for large statistical models, and to build other new features into NIMBLE.

The work will involve programming in R and C++, primarily designing and implementing software involving automated generation of C++ code for class and function definitions, parallel computing, use of external libraries for automatic differentiation and linear algebra, statistical algorithms and related problems. The position will also involve writing documentation and following good open-source software practices.

See here to apply.

Version 0.6-3 released.

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Version 0.6-3 is a very minor release primarily intended to address some CRAN packaging issues that do not affect users. We also fixed a bug involving MCEM functionality and a bug that prevented use of the sd() and var() functions in BUGS code.

For most users, there is probably no need to upgrade from version 0.6-2.

Version 0.6-2 released!

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Version 0.6-2 is a minor release with a variety of useful functionality for users.

Changes as of Version 0.6-2 include:

  • user-defined distributions can be used in BUGS code without needing to call the registerDistributions() function (unless one wants to specify alternative parameterizations, distribution range or that the distribution is discrete),
  • users can now specify the use of conjugate (Gibbs) samplers for nodes in a model,
  • NIMBLE will now check the run code of nimbleFunctions for functions (in particular R functions) that are not part of the DSL and will not compile,
  • added getBound() functionality to find the lower and upper bounds of a node either from R or in DSL code,
  • added functionality to get distributional information about a node in a model or information about a distribution based on the name of the density function; these may be useful in setup code for algorithms,
  • multinomial and categorical distributions now allow ‘probs’ arguments that do not sum to one (these will be internally normalized) and
  • a variety of bug fixes.

Please see the NEWS file in the installed package for more details.

Version 0.5-1 of NIMBLE released!

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Version 0.5-1 is officially a minor release, but it actually has quite a bit in it, in particular the addition/improvement of a number of our algorithms. In addition there are some more improvements in our speed in building and compiling models and algorithms.

Changes as of Version 0.5-1 include:

  • the addition of a variety of sequential Monte Carlo (aka particle filtering) algorithms, including particle MCMC samplers for use within an MCMC,
  • a greatly improved MCEM algorithm with an automated convergence and stopping criterion,
  • new syntax for declaring multivariate variables in the NIMBLE DSL, namely numeric(), integer(), matrix(), and array(), with declare() now deprecated,
  • addition of the multivariate-t distribution for use in BUGS and DSL code,
  • a new binary MCMC sampler for discrete 0/1 nodes,
  • addition of functionality to our random walk sampler to allow sampling on the log scale and use of reflection,
  • more flexible use of forwardsolve(), backsolve(), and solve(), including use in BUGS code, and
  • a variety of other items.

Please see the NEWS file in the source package.

Version 0.5 released!

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We’ve just released the next major version of NIMBLE.

Changes include

  • more efficient computations for conjugate sampling,
  • additional automated checking of BUGS syntax to improve NIMBLE’s warning/error messages,
  • new API functionality to allow the use of syntax such as model$calculate(), etc. (syntax such as calculate(model) still works),
  • new API functionality for MCMC sampler specification,
  • improvements in speed and memory use in building models,
  • addition of forwardsolve, backsolve, and solve to the NIMBLE DSL, and
  • a variety of other items.

More details in the NEWS file that accompanies the package.

We anticipate being on CRAN in coming weeks and a next release soon that will include a full suite of sequential Monte Carlo (i.e., particle filtering) algorithms.

Version 0.4-1 released!

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We’ve just released version 0.4-1, a minor release that fixes some logistical issues and adds a bit of functionality to our MCMC engine.

Changes as of Version 0.4-1 include:

  • added an elliptical slice sampler to the MCMC engine,
  • fixed bug preventing use of nimbleFunctions in packages depending on NIMBLE, and
  • reduced C++ compiler warnings on Windows during use of compileNimble.