NetKet is participating in the 2022 edition of UnitaryHack, kindly sponsored by the quantum nonprofit Unitary Fund.
The hackathon will run for two weeks, from Friday, June 3 to Friday, June 17. During the hackathon, several highprofile quantum software projects are each proposing several tasks for which Unitary Fund will provide a bounty to the participant completing the task.
NetKet is participating with 4 bounties to this hackathon, which are worth US$ 300 in total. To claim a bounty, you need to get a PR accepted (not necessarily merged) by the maintainers before the end of the hackathon. The precise instructions to follow are found in the UnitaryHack website and the list of bounties can be found here.
We are offering the following 4 bounties, some of which don’t require particular experience with quantum physics but which will benefit the usability of the NetKet project as a whole:

#1200 Add support for a singlefile HDF5 based logging sink ($75)
HDF5 is a commonly used fileformat that can store any kind of data. We would like contributors to implement a logger that can output this kind of files. No experience with quantumrelated topics is required to win this bounty!

#1201 Use colors to signal bad sampling in expectation value/samplers state ($50)
Sometimes users get bad results when running simulations with NetKet, but don’t notice that there are sampling errors and that the software is already hinting at the solution. As this error is very common between novices and new users, we would like to integrate with the rich framework to display statistical convergence indicators using colors that vary depending on whether their value is good or bad.

#1206 Implement support for Ladder operators in PauliStrings ($100)
NetKet implements several kind of specialized types of operators which behave somewhat like a sparse matrix, but can encode operators in Hilbert spaces much larger than 2^64, and which are much more efficient at the operations that we require for MonteCarlo algorithms. One of those operators is the
PauliStrings
operator, very similar to qiskit’s and Pennylane’sPauliStringSum
operators. Right now it supports the “X,Y,Z,I” operators, but we would like to add support for ladder operators. To work on this task, you’ll need some knowledge of linear algebra/elementary quantum mechanics. 
#1220 Add singlepass online statistics support to NetKet ($75)
The algorithms used by NetKet to compute statistical estimators and convergence indicators require that the whole set of random variables be kept in memory. However, in the future we would like to estimate those observables on amounts of data so large that do not fit on the memory of the device. Therefore, this bounty is about implementing singlepass algorithms that can estimate relevant quantities by reading the data only once. To work on this bounty, you’ll need a basic understanding of statistics.
If you are interested in those projects, but are unsure of where to start from, do get in touch with us through NetKet’s Slack channel or by launching a discussion on GitHub.
We are really looking forward to welcoming new contributors to the project!