Error "value cannot be converted to type uint8_t without overflow"

[fxcoudert]

Hi, I have compiled a new LAMMPS-with-MACE version and I was trying to run some of our older simulations, to check that the new compile is sane. But I get an unusual error:

Setting up Verlet run ...
  Unit style    : metal
  Current step  : 0
  Time step     : 0.0005
Exception: value cannot be converted to type uint8_t without overflow

I have no idea where that comes from. I'm running on new H100 NVL hardware, but we have previously run this model on V100 and A100 with no problem. I'm wondering if someone has every seen this error (search leads to no result) or knows how to debug it?

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The full input is found there, including our models: https://github.com/fxcoudert/citable-data/tree/master/176-Triestram_ChemSci_2026

The command line is lmp -k on g 1 -sf kk -pk kokkos newton on neigh half -in ZIF4_CPII.in

The full output is:

LAMMPS (10 Sep 2025)
KOKKOS mode with Kokkos version 4.6.2 is enabled
  using double precision
  using view layout = legacy
  will use up to 1 GPU(s) per node
  using 1 OpenMP thread(s) per MPI task
Reading restart file ...
  restart file = 29 Aug 2024, LAMMPS = 10 Sep 2025
  restoring atom style atomic/kk from restart
  triclinic box = (-0.10289585 0.0018019543 0.25034589) to (30.949096 30.806598 36.625454) with tilt (0.089201414 -0.11390423 -0.015787914)
  1 by 1 by 1 MPI processor grid
  restoring pair style mace/kk from restart
WARNING: Pair style restartinfo set but has no restart support (src/pair.cpp:762)
  2176 atoms
  read_restart CPU = 0.010 seconds
Changing box ...
  triclinic box = (-0.10289585 0.0018019543 0.25034589) to (30.949096 30.806598 36.625454) with tilt (0.089201414 -0.11390423 -0.015787914)
CUDA found, setting device type to torch::kCUDA.
Loading MACE model from "MACE_ZIF4_stress100_compiled.model-lammps.pt" ... finished.
  - The torch_float_dtype is: Byte
  - The r_max is: 6.
  - The model has: 2 layers.
  - The MACE model atomic numbers are: 1 6 7 30.
  - The pair_coeff atomic numbers are: 6 1 7 30.
  - Mapping LAMMPS type 1 (C) to MACE type 2.
  - Mapping LAMMPS type 2 (H) to MACE type 1.
  - Mapping LAMMPS type 3 (N) to MACE type 3.
  - Mapping LAMMPS type 4 (Zn) to MACE type 4.
Resetting global fix info from restart file:
  fix style: npt/kk, fix ID: 4
Generated 0 of 6 mixed pair_coeff terms from geometric mixing rule
All restart file global fix info was re-assigned
Neighbor list info ...
  update: every = 1 steps, delay = 0 steps, check = no
  max neighbors/atom: 2000, page size: 100000
  master list distance cutoff = 13
  ghost atom cutoff = 13
  binsize = 13, bins = 3 3 3
  1 neighbor lists, perpetual/occasional/extra = 1 0 0
  (1) pair mace/kk, perpetual
      attributes: full, newton on, kokkos_device
      pair build: full/bin/kk/device
      stencil: full/bin/3d
      bin: kk/device
Setting up Verlet run ...
  Unit style    : metal
  Current step  : 0
  Time step     : 0.0005
Exception: value cannot be converted to type uint8_t without overflow

[ilyes319]

Hey @fxcoudert, never seen that error, going to investigate. Thanks for posting.

[fxcoudert]

Finally figured it out, and I am very sorry, because it's a “Problem Existing Between the Keyboard and the Chair” issue. I wrongly compiled the model for LAMMPS, causing the error. Once I recompiled properly using create_lammps_model.py, all is now good.

Apologies for the noise.