USPEX25: heredity_finalMP_var_py fails with IndexError

[Niklas Langer]

I'm doing a variable composition calculation for a ternary system using USPEX25. which runs locally (no job submission). After 1 generation USPEX gets stuck when generating a new structure by heredity. Before the error happens the output shows a few warnings:

[WARNING] Heredity failed to produce a valid structure, elapsed 0.0s
[WARNING] Switch to fallback generator: Pyxtal.

This happens a couple of times and in the end USPEX gets completely stuck while generating a new structure. I let it continue for about a day but it didn't manage to do anything. The "warnings" file shows the following output (multiple times):

[2025-11-14T15:43:24] sc_heredity_varcomp: var_operator=HeredityVarcomp.produce_structure(parent1_system_number=64, parent2_system_number=73) (system_number=275)
IndexError: index 25 is out of bounds for axis 0 with size 25
Traceback (most recent call last):
  File "/home/niklas/.cache/uspex_sfx/fc4a08e65ffc5f4fc3b45cb058de2cd54731ab2c191123aac8a3c69e87e95c8c/uspex_core/src/main_algorithm/algorithm_stages/components/new_generation_creation/generators/components/structure_creators/implementations/evolutionary_crossover.py", line 75, in produce_structure
  File "/home/niklas/.cache/uspex_sfx/fc4a08e65ffc5f4fc3b45cb058de2cd54731ab2c191123aac8a3c69e87e95c8c/uspex_core/src/main_algorithm/algorithm_stages/components/new_generation_creation/generators/components/variation_operators/variation_operators_crystal/heredity_varcomp.py", line 165, in produce_structure
  File "/home/niklas/.cache/uspex_sfx/fc4a08e65ffc5f4fc3b45cb058de2cd54731ab2c191123aac8a3c69e87e95c8c/uspex_core/src/common/heredity_varcomp/heredity_core_varcomp.py", line 496, in heredity_finalMP_var_py
IndexError: index 25 is out of bounds for axis 0 with size 25

Thanks in advance if you have any ideas how to fix this :D