What’s new

The main changes for users, newest first. The Changelog lists every change in detail.

`dev-next`, not yet released

Compared with the version most collaborators used in 2025, the dev branch.

Galactic noise is \(\sqrt{2}\) larger. Since 7 September 2026 the simulated noise has the level its tables specify; before, it was \(\sqrt{2}\) too low. The three antenna models (GP300, GP300_nec, GP300_mat) now each read their own table. Voltage files record the GRANDlib version that wrote them, so files from before the change can be told apart (Voltages simulated before 7 September 2026).
No antenna response from below the horizon. A source more than 90° from the zenith used to read the response of a direction above the antenna, at full strength. It now gives zero, with a warning.
CoREAS conversions have the right azimuth. The converter mirrored the azimuth of inputs without a shower block; files converted from those should be converted again.
sim2root writes the right antenna coordinates. With several events sharing antennas, du_geoid could be assigned to the wrong antennas, up to 8 km off.
The resampled voltage is consistent. Resampling in Efield2Voltage used to leave the trigger position and the run’s time step at the input rate, so the ADC step misread the traces. Resample the electric field with convert_efield2efield.py instead.

Reconstruction, in grand.analysis: arrival direction, the position of Xmax and an energy estimate from recorded times and amplitudes, with Cramér-Rao bounds (notebook 11).
An offline T1 trigger, convert_voltage2adc.py --t1_trigger (Command-line tools).
Files record the code that wrote them: the GRANDlib version and git commit, in every tree written.
Clear errors. Public functions check their input and say what is wrong in a message that starts with GRANDlib: (Troubleshooting).
One installation route: a single conda environment and an installable package (Installation and requirements).
Documentation: this site, with a quick start, recipes and twelve notebooks and notebooks/import_notebook.py to add or edit a notebook.

import grand no longer needs ROOT. Reading files no longer loads the simulation code.
Trees are released when no longer referenced, so reading many files no longer exhausts memory (Reading many files: release each tree).
Two processes writing the same file are refused instead of corrupting it.
The tree classes work with NumPy 2.