zhubonan / castepxbin Goto Github PK

These should be trivial to read, but knowledge of the number of bands/kpoints/spins are needed in the first place. One can parse the <seed>.bands file first to get those in the first place.

I can copy the bands parser from aiida-castep into this package to do this.

Hi Bonan Zhu,
First of all Happy New and stay blessed. I am a PhD student and using CASTEP interface in Materials Studio for my research. I want to study the projected band structure of heterostructures but unfortunately there is no such option in Materials Studio. Although, I can calculate the pdos by using OptaDOS of Materials Studio files ( .bands, .cell and .pdos_bin). In a similar way, I tried to use the .band and .cell (from spectral band structure calculation) and .pdos_bin (from pdos calculation because CASTEP interface in Materials Studio doesn't generate the .pdos_bin in spectral band structure calculation). But i got the following error.
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

May be there is some error while reading the .pdos_bin file. Then, I come to know with castepxbin we can read the .pdos_bin file. I am not much familiar with coding. So, i don't know how to use castepxbin to read the .pdos_bin file. Could you please help me in this regards? Thank you in advance.
Looking forward to your kind response.

Best Wishes
Sajid

Support for parsing check and castep_bin files would be very useful. Some properties are not printed in the text .castep output or at least for a high precision (e.g. forces).

We can search through the Fortran records inside the binary files for certain header contains (CHAR of length < 256), record the position of the headers in the first pass and read required properties in a second pass.

This would probably require us to implement a FortranRecord class for handling the record markers and contents.

The immediate use case would be for parsing high-quality forces for external finite-difference phonons using tools such as phonopy and when integrated with AiiDA (for aiida-castep and aiida-phononpy).

Many more quantities can also be extracted and opening up more post-processing opportunities.

Existing binary parsing utilities:

• https://github.com/pace-neutrons/Euphonic/blob/master/euphonic/readers/castep.py: we can improve upon this and make it more general.
• c2x, but it is written in C, and only for certain properties.

There is a useful Fortran file parsing package implemented for Julia: https://traktofon.github.io/FortranFiles.jl/v0.4/. We can use similar concepts (e.g. similar to the Record type). Sub-record support can be useful but not mandatory as a single record size from CASTEP is not expected to exceed 2GB.

NOTE: castep binary files are big-endian (enforced at compile time).