SciML Small Grants Program Current Project List

The following is the current project list for the SciML Small Grants Program.

Rules and Regulations

The small grant projects are decided by the SciML Steering Council and candidates can choose to take on projects from the project list. This is similar to "bounty programs" seen in other open source environments, though it is driven by SciML in a manner that is designed to give better outcomes to both contributors and maintainers of the project. In order to remove a hostile competitive atmosphere, candidates must declare to the committee interest before solving the chosen issue and, upon approval by the selection committee, are given an exclusive time interval (defaulting to one month) to solve the issue. Payout is done upon completion of the chosen project and acceptance by the steering council.

All projects are expected to contribute the code to repositories in the SciML Github organization. Code which is not contributed to the open source repositories will not be considered in the approval evaluations.

Declaring for a Project

To declare for a small grant program, send an email to sciml@julialang.org with:

The potential reviewers will then get in touch to clarify details of the project and establish a clear work statement. Once clarifed, steering council will then respond with whether the application is accepted and commence the work under the supervision of the reviewer. When the reviewer accepts and merges the appropriate PRs, the grant will be determined as completed and the payout will commence. The grants are project based and payout will only occur upon acceptance by the reviewer.

Note that information about ongoing projects will be tracked as public information below in order to give clear information to other contributors about what projects are taken. Completed projects will be added to a projects archive.

Donating to the Program

If you wish to donate to the SciML Small Grants Program, please donate via NumFOCUS. SciML via NumFOCUS is a 501(c)(3) public charity in the United States. Your donation is tax-deductible to the extent provided by US law. General donated funds are used for the developer programs such as the small grants program and the SciML Fellowship.

Donations can be earmarked towards specific projects. In order for an earmarked project to become a part of the SciML Small Grants program it must be approved by the SciML Steering Council. The reason why all chosen projects must be vetted by the Steering Council is that we want to be fair to the potential contributors, and this means we must ensure that the suggested projects will have a prompt review process and proper maintanance beyond the timeframe of the project. For this reason, we suggest discussing with maintainers in the official Slack/Zulip before making an earmarked donation.

Commitments from Reviewers

Reviewers are committed to giving timely feedback and reviews. It is expected that you keep in constant touch with the reviewer during the duration of the project, discussing on one of the community chat channels at least a few times a week until project completion. Discussions should take place in the SciML Slack or Zulip channels (#diffeq-bridged or #sciml-bridged) to allow for other contributors to give feedback. Reviews of PRs should be expected within a few days to ensure the contributor can complete the project in the allotted time frame.

However, it is also expected that the contributor can work fairly independently with guidance from the reviewer. Contributors are expected to be comfortable enough in the area of expertise to work through the errors and test failures on their own. The SciML Small Grants Program is not a training program like Google Summer of Code or the SciML Fellowship, and thus the reviewer is not expected to mentor or teach the contributor how to solve the problem. The reviewer is in no obligation to help the contributor work through tests, bug fixing, etc. as these projects were chosen due to the fact that the maintainers have not been able to find the time to cover these areas. The obligation of the reviewer is to give a timely feedback on what the requirements for merging would be (i.e. what tests are required to be added, whether certain code meets style demands, etc.) so that the contributor can achieve a mergable PR within the time frame, but there is no expectation that the reviewer will "go the extra mile" to teach the contributor how the package or mathematics works.

List of Current Projects

Fix and Update the "Simple Handwritten PDEs as ODEs" Benchmark Set ($200)

The "Simple Handwritten PDEs as ODEs" benchmarks have been failing for awhile. They need to be updated to the "new" linear solve syntax introduced in 2022. When updated, these benchmarks should serve as a canonical development point for PDE-specific methods, such as implicit-explicit (IMEX) and exponential integrators.

Information to Get Started: The Contributing Section of the SciMLBenchmarks README describes how to contribute to the benchmarks. The benchmark results are generated using the benchmark server. Half of the benchmarks are setup using hand-discretized finite difference stencils for the PDE, the other half use ApproxFun.jl in order to do a pseudospectral discretization. A direct pseudospectral discretization via manual FFTs and operator construction would also be fine.

Related Issues: https://github.com/SciML/SciMLBenchmarks.jl/issues/929

Success Criteria: Pull requests which update the benchmarks in the folder to be sucessful with current Julia and package version (v1.10) without erroring, generating work-precision diagrams. In addition, these should be updated to give a more clear definition of the PDE being solve, adding a LaTeX description of the equations to the top of the file.

Recommended Skills: Basic (undergrad-level) knowledge of finite difference and pseudospectral PDE discretiations.

Reviewers: Chris Rackauckas

Update BlackBoxOptimizationBenchmarking.jl to the Optimization.jl Interface and Add to SciMLBenchmarks ($300)

In Progress: Claimed by Edward Berman for the time period of May 6th, 2024 - June 6th 2024.

BlackBoxOptimizationBenchmarking.jl is a very interesting set of benchmarks between global optimization tools. However, it has not been updated in years. It would be useful to the community if this set of benchmarks was updated to the modern SciML interfaces and benchmarking tools so it can make use of the full set of methods in Optimization.jl and drive further developments and recommendations to users.

Information to Get Started: The Contributing Section of the SciMLBenchmarks README describes how to contribute to the benchmarks. The benchmark results are generated using the benchmark server. It is expected that the benchmarks are updated to use the Optimization.jl interface, which is an interface over most optimizers in Julia. Not all of the optimizers are covered in this interface: simply remove the optimizers which are not wrapped into Optimization.jl

Related Issues: https://github.com/SciML/SciMLBenchmarks.jl/issues/640

Success Criteria: The benchmarks should be turned into a loop over Optimization.jl solvers in a standard SciMLBenchmarks benchmark build.

Recommended Skills: Basic (undergrad-level) knowledge of using numerical optimizers

Reviewers: Chris Rackauckas and Vaibhav Dixit

Update CUTEst.jl to the Optimization.jl Interface and Add to SciMLBenchmarks ($200)

CUTEst.jl is a repository of constrained and unconstrained nonlinear programming problems for testing and comparing optimization algorithms. We would like to be able to repurpose this work for improving Optimization.jl's performance and tracking the performance of optimizers. It would be useful to the community if this set of benchmarks was updated to the modern SciML interfaces and benchmarking tools so it can make use of the full set of methods in Optimization.jl and drive further developments and recommendations to users.

This would likely turn into either contributions to CUTEst or wrappers to CUTEst (hosted in SciML) which which transform the NLPModels form into Optimization.jl, and a benchmarking script that loops over all optimization problems and applies a set of optimizers to each of them, computing summary statistics at the bottom.

Information to Get Started: The Contributing Section of the SciMLBenchmarks README describes how to contribute to the benchmarks. The benchmark results are generated using the benchmark server. It is expected that the benchmarks are updated to use the Optimization.jl interface, which is an interface over most optimizers in Julia. Not all of the optimizers are covered in this interface: simply remove the optimizers which are not wrapped into Optimization.jl

Related Issues: https://github.com/SciML/SciMLBenchmarks.jl/issues/935

Success Criteria: The benchmarks should be turned into a loop over Optimization.jl solvers in a standard SciMLBenchmarks benchmark build.

Recommended Skills: Basic (undergrad-level) knowledge of using numerical optimizers

Reviewers: Chris Rackauckas and Vaibhav Dixit

Refactor OrdinaryDiffEq.jl to use Sub-Packages of Solvers ($300)

It's no surprise to anyone to hear that DifferentialEquations.jl, in particular the OrdinaryDiffEq.jl solver package, is very large and takes a long time to precompile. However, this is because there are a lot of solvers in the package. The goal would be to refactor this package so that sets of solvers are instead held in subpackages that are only loaded on-demand. Since many of the solvers are only used in more niche applications, this allows for them to be easily maintained in the same repo while not imposing a loading cost on the more standard appliations.

Information to Get Started: The OrdinaryDiffEq.jl solvers are all found in the Github repository and the format of the package is docmented in the developer documentation

Related Issues: https://github.com/SciML/OrdinaryDiffEq.jl/issues/2177

Success Criteria: The independent solver packages are registered and released, and a breaking update to OrdinaryDiffEq.jl is released which reduces the loading time by not including all solvers by default. This success also requires updating package documentation to reflect these changes.

Recommended Skills: Since all of the code for the solvers exists and this a refactor, no prior knowledge of numerical differential equations is required. Only standard software development skills and test-driven development of a large code base is required.

Reviewers: Chris Rackauckas

Refactor OrdinaryDiffEq.jl Solver Sets to Reuse perform_step! Implementations via Tableaus ($100/solver set)

The perform_step! implementations per solver in OrdinaryDiffEq.jl are often "bespoke", i.e. one step implementation per solver. The reason is because the package code grew organically over time and this is the easiest way to ensure performance and write out a new method. However, many of the methods can be collapsed by class into a single solver set using a tableau implementation that loops over coefficients. Because of the nuances in performance and implementation, we have avoided doing this refactoring until a few more pieces were set in stone.

Note that this should be done based on classes of solvers, as documented in the code as files in the perform_step! implementations (though the explicit Runge-Kutta methods are split across a few files and should all be a single tableau). Solver set should be discussed before starting the project.

It is recommended that implicit methods such as Rosenbrock and SDIRK integrators are done first, as the extra intricacies of their algorithm make this refactor simpler because the nuances of the implementation are less likely to noticably impact performance.

Information to Get Started: The OrdinaryDiffEq.jl solvers are all found in the Github repository and the format of the package is docmented in the developer documentation. The key to doing this right is to note that it is just a refactor, so all of the methods are there in the package already. However, note that some methods can be a bit nuanced, for example, BS5 and DP8 use fairly non-standard error estimators for an explicit Runge-Kutta method, while Verner methods have a twist with laziness. Because of this, the key is to be careful to add points to dispatch to alternative based on the nuances of the given algorithms.

Related Issues: https://github.com/SciML/OrdinaryDiffEq.jl/issues/233

Success Criteria: The independent solver packages are registered and released, and a breaking update to OrdinaryDiffEq.jl is released which reduces the loading time by not including all solvers by default. This success also requires updating package documentation to reflect these changes.

Recommended Skills: Since all of the code for the solvers exists and this a refactor, no prior knowledge of numerical differential equations is required. Only standard software development skills and test-driven development of a large code base is required.

Reviewers: Chris Rackauckas

Update LoopVectorization to Support Changes in Julia v1.12 ($200)

In Progress: Claimed by Miguel Raz Guzman for the time period of May 10th, 2024 - June 10th 2024.

LoopVectorization.jl is a central package for the performance of many Julia packages. Its internals make use of many low-level features and manual SIMD that can make it require significant maintanance to be optimized for new versions of the compiler.

Information to Get Started:

With Julia v1.12:

The purpose of this project is to update LoopVectorization.jl, VectorizationBase.jl, SLEEFPirates.jl and the rest of the JuliaSIMD ecosystem so that all the llvmcalls use opaque pointers, and any Ptr arguments or returns are llvm ptrs instead of integers. LoopVectorization.jl tests should pass under --depwarn=error.

Note that the funds for this project as given by earmarked donations to the JuliaLang project which SciML will help administer through the small grants program.

Success Criteria: LoopVectorization.jl runs on v1.12's latest release.

Recommended Skills: This requires some low-level knoweldge of LLVM IR and familiarity with llvmcall. The changes should be routine.

Reviewers: Chris Elrod